University of North Florida
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Stuart Chalk, Ph.D.
Department of Chemistry
University of North Florida
Phone: 1-904-620-1938
Fax: 1-904-620-3535
Email: schalk@unf.edu
Website: @unf

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Column

Classification: Manifold component -> Column

Citations 442

"On The Signal Response Of Various Pesticides In Electrospray And Atmospheric Pressure Chemical Ionization Depending On The Flow-rate Of Eluent Applied In Liquid Chromatography-tandem Mass Spectrometry"
J. Chromatogr. A 2001 Volume 937, Issue 1-2 Pages 65-72
Arndt Asperger, Jürgen Efer, Therese Koal and Werner Engewald

Abstract: The API-MS signal response of several pesticides (atrazine, simazine, isoproturon, diuron, chlorfenvinphos, chlorpyrifos, alachlor, trifluralin) depending on the flow-rate of eluent entering the MS interface was investigated. The investigations were based on API-MS-MS analyzes of standard pesticide mixtures in the flow injection mode (FIA) at systematically varied eluent flow-rates using both an ESI interface (Turboionspray) and a heated nebulizer type APCI source. In the result, the individual compounds included in this study showed significant differences in their signal response behavior depending on the flow-rate of eluent applied. The most hydrophobic compounds among the investigated pesticides (chlorpyrifos and trifluralin) showed drastic losses of sensitivity with increasing eluent flow-rate in both ESI and APCI, while more hydrophilic compounds like atrazine, simazine and isoproturon showed the expected signal response (concentration-sensitive in ESI, mass-flow-sensitive in APCI) at least within a certain range of flow-rates (200-600 µL/min in ESI, 200-2000 µL/min in APCI). These findings lead to the conclusion that application of a programmed HPLC eluent flow-rate may be advantageous to achieve maximum sensitivity of API-MS detection for all pesticides of interest. This is exemplified by the implementation of a flow gradient into an online SPE-HPLC-APCI-MS/MS method for improved analysis of pesticides in drinking water. (C) 2001 Elsevier Science B.V. All rights reserved.

"Optimization Of Flame Atomic Absorption Spectrometry With Preconcentration By Flow Injection Online Sorbent Extraction Of Cadmium And Lead In Biological Materials"
Bol. Soc. Chilena Quim. 1999 Volume 44, Issue 3 Pages 321-335
BRUHN, CARLOS G., VILCHES, CAROLINA and CID, HERNAN J.

Abstract: A flow injection (FI) system with a minicolumn of bonded silica with octadecyl groups (C-18) to collect diethyldithiocarbamate complexes of Cd and Pb in reference solutions and in acid-digested hair and blood solutions was developed and evaluated by flame atomic absorption spectrometry (FAAS). The system was optimized by multivariate method, based on a factorial experimental design in two levels, selecting eight parameters that mostly affected the expected analytical signal. The detection limits (3s(BL)/slope, 60 s pre-concentration) were 0.7 and 5 µg/L for Cd and Pb, respectively and the sampling frequency was 40 samples/h. Effects of interfering ions are discussed. The methodology was validated by analysis of certified reference materials of hair and blood for Pb, and by recoveries of Cd and Pb spikes performed in hair and blood samples. Results for Pb agreed well with certified values and recoveries were satisfactory (103% in blood and 100% in hair). Also, the recovery of Cd in hair was fair (107%); however, in blood it was not quantitative (22%).
Cadmium Lead Hair Blood Spectrophotometry

"Analysis Of Pesticide Residues In Matrices With High Lipid Contents By Membrane Separation Coupled On-line To A High-performance Liquid Chromatography System"
J. Chromatogr. A 2000 Volume 869, Issue 1-2 Pages 427-439
R. Carabias-Martínez, E. Rodríguez-Gonzalo, P. H. Paniagua-Marcos and J. Hernández-Méndez

Abstract: Separation through membranes coupled to an HPLC system was used as a technique for the analysis of pesticide multiresidues in samples with high lipid contents. As well as the usual procedure, in the proposed system it is possible to recirculate the sample through the membrane cell, which permits the extraction system to be applied to cases in which only a very small volume of sample is available. A procedure for pesticide multiresidue analysis in egg samples was developed as a representative example of the applicability of the proposed method. To accomplish this, the analytes (dichlorvos, dimethoate, propoxur, paraoxon, pirimicarb, atrazine, ametryne, terbutryne, azinphos-methyl, folpet) were subjected to prior extraction in a Soxhlet system, after which the extract was introduced into the membrane separation device coupled to the HPLC system. This procedure afforded clean chromatograms, hence considerably facilitating determination, and at the same time was efficient in removing macromolecular compounds. For egg samples, spiked at a concentration level of 0.750 mg/kg, recoveries ranged from 60 to 98%. The detection limits varied from 0.018 mg/kg for dichlorvos to 0.002 mg/kg for atrazine.

"Sequential Injection Spectrophotometric Analysis Of Nitrite In Natural Waters Using An On-line Solid-phase Extraction And Preconcentration Method"
Analyst 2000 Volume 125, Issue 5 Pages 943-948
Manuel Miró, Andreu Cladera, José Manuel Estela and Víctor Cerdà

Abstract: An automatic sequential injection analysis (SIA) set-up for the isolation, pre-concentration and spectrophotometric determination of nitrite in waters based on the Shinn reaction was designed and evaluated. The system performs the on-line azo dye formation and its subsequent extraction on a solid phase (monofunctional C-18), which is held inside a glass column incorporated into the system. A large sample volume (maximum, 10 mL) is sequentially segmented with sulfanilamide and N-(1-naphthyl)ethylenediamine dihydrochloride by using an iterative method. The azo dye collected is eluted with a small volume of 80% methanol and conducted to a diode-array spectrophotometer for quantitative analysis. It has been proved that the retention efficiency is maintained for up to 45 sample injections of 10 mL in spite of the high chromogenic reagent acidity. Nitrite has been determined within the 13.4-160 ng mL-1 and 0.83-20 ng mL-1 ranges for 1 and 10 mL of sample, respectively. For these volumes, the detection limits are 5.9 and 0.32 ng mL-1, the enhancement factors 17 and 170 and the sample throughput 15 and 3 h-1, respectively. A maximum RSD of 4.0% was achieved in all determinations. It is an advantage of this approach that it is possible to use the same mass calibration graph for any sample volume.
Nitrite Rain Water Spectrophotometry

"Fast Sequential Injection Determination Of Benzo[A]pyrene Using Variable Angle Fluorescence With On-line Solid-phase Extraction"
Analyst 2001 Volume 126, Issue 4 Pages 451-456
J. A. Erustes, A. Andrade-Eiroa, A. Cladera, R. Forteza and V. Cerdà

Abstract: A methodology for the analysis of drinking water for one of the most potent carcinogenic agents known; benzo[a]pyrene (BaP), in the presence of other interfering PAHs is presented. The methodology described is based on the sequential injection analysis of the sample on to a microcolumn (containing 5 mg of C-18) where extraction and pre-concentration of BaP takes place, followed by elution of BaP with 1 mL of 1,4-dioxane and subsequent detection by using variable angle fluorescence. The advantages of the method include the small amount of stationary phase employed together with the possibility of re-using the phase in order to carry out a large number of injections without the need for column re-packing. Also noteworthy is the small volume of 1,4-dioxane used to elute the BaP retained on the column and the small sample volumes required (9-10 mL) for achieving detection limits at the ng L-1 level. Thus, a methodology for BaP determination is obtained which complies with the requirements of the 98/83/EC Directive which fixes a maximum admissible concentration for this pollutant in waters for public consumption of 10 ng L-1. The variable angle spectra obtained are further processed by means of the multiple linear regression technique. The detection limit for BaP is 2.5 ng L-1, and the linear range is between 7.5 and 280 ng L-1.
Benzo(a)pyrene Water Fluorescence

"Multisyringe Flow Injection Spectrofluorimetric Determination Of Warfarin At Trace Levels With On-line Solid-phase Preconcentration"
Anal. Chim. Acta 2002 Volume 467, Issue 1-2 Pages 13-23
Graciela de Armas, Manuel Miró, José Manuel Estela and Víctor Cerdà

Abstract: Warfarin (3-(α-acetonylbenzyl)-4-hydroxycoumarin) is a widely used anticoagulant rodenticide which has strong toxic effects in humans and animals. A new multisyringe flow injection analysis (MSFIA) set-up for the spectrofluorimetric determination of warfarin in waters at trace levels is presented. Preconcentration on a solid-phase (octadecyl chemically-bonded silica-gel-based beads) without prior derivatization, and elution with dimethyl sulfoxide (DMSO) containing monomeric units of the cetyltrimethylammonium chloride (HTAC) surfactant resulted in a quantification limit (50 ng L-1) lower than those reported to date, reaching the levels demanded by regulatory authorities in drinking waters. Several variables such as eluent composition, sample and eluent volumes, retention and elution flow rates and sample pH were studied in detail. A mass calibration may be used to determine warfarin in the wide range from 50 ng L-1 to 64 µg L-1 for sample volumes between 0.2 and 12 mL. An enrichment factor of 155, a sample throughput of 12 hr-1 and a repeatability better than 2% were achieved by pre-concentration of 16 ng of the target compound from 2 mL of sample.
Warfarin Mineral Rain Ground Fluorescence

"Online Trace Enrichment And Determination Of Cobalt Ion As An Anionic Complex By Flow Injection Atomic Absorption Spectrometry"
Microchem. J. 1999 Volume 63, Issue 2 Pages 226-234
Shayessteh Dadfarnia and Mohammad Hossein Jafarzadeh

Abstract: A flow injection system incorporating a microcolumn of activated alumina was combined with atomic absorption spectrometry for online trace enrichment and determination of cobalt in waters and vitamin B-12. Deposition of cobalt as its cyano complex was effected with the use of an acidic alumina microcolumn, and injection of ammonia solution (500 µl, 2 M) served to elute species retained on the atomic absorption spectrometer. A sample volume of 15 mL resulted in a pre-concentration factor of 120, and precision at the 500 and 50 µg L-1 levels was±3.1 and±3.3% (RSD), respectively. The procedure was applied to mineral water, spring water, river water, and vitamin B-12 and accuracy was assessed through a recovery experiment.

"Synthetic Zeolites As Sorbent Material For On-line Preconcentration Of Copper Traces And Its Determination Using Flame Atomic Absorption Spectrometry"
Anal. Chim. Acta 2000 Volume 403, Issue 1-2 Pages 249-258
Yaneira Petit de Peña, Wilmer López, José Luis Burguera, Marcela Burguera, Máximo Gallignani, Rosario Brunetto, Pablo Carrero, Carlos Rondon and Freddy Imbert

Abstract: This work assesses for the first time the potential of synthetic zeolites as adsorptive material for the pre-concentration of copper traces. This involves the formation of a copper chelate, its adsorption on sodium lynde Type A (Na-LTA) and sodium faujasite Type X (Na-Fau) synthetic zeolite minicolumns, and its elution with 300 µl of methyl isobutyl ketone. Using 5-80 mg of either sorbents materials with a loading time of 2 min per sample pre-concentration factors of copper ranging from 35-125 for Na-LTA and 3065 for Na-Fau were readily achieved related to the direct introduction of aqueous solutions into an atomic absorption spectrometer. To evaluate the performance of these materials, a flow injection system was used for samples of water from different sources, and the accuracy was assessed through recovery experiments and the analysis of certified reference materials. A parallel experiment was performed with polygosyl bonded silica reversed-phase sorbent with octadecyl functional groups (RP-C-18) as sorbent in the minicolumn in order to study the performance of this. well-known material as a reference for the new sorbents. The 3s detection limits, relative standard deviation and linear calibration graphs were, respectively, 0.1 ng mL-1, 2.6% and 2.5-30 ng mL-1 for Na-LTA and 0.4 ng mL-1, 2.8% and 2.5-40 ng mL-1 for Na-Fau for pre-concentration times of 2 min.
Copper Sea Spectrophotometry

"Solid-phase Reactor With Copper(II) Phosphate For Flow Injection Spectrophotometric Determination Of Aspartame In Tabletop Sweeteners"
Anal. Chim. Acta 1999 Volume 384, Issue 2 Pages 167-174
Orlando Fatibello-Filho, Luiz Humberto Marcolino-Juniorand Airton Vicente Pereira

Abstract: A flow injection spectrophotometric method was developed for determining aspartame in tabletop sweeteners. Samples were dissolved in water and 250 µl of the solution were injected into a carrier stream of 5.0 x 10^-3 mol L-1 sodium berate solution (pH 9.0). The sample flowed through a column (13 cm x 2.0 mm) packed with Cu-3(PO4)(2) immobilized in a matrix of polyester resin and Cu(II) ions were released from the solid-phase reactor by the formation of Cu(II)(aspartame)(2) complex. The mixture merged with a stream of berate buffer solution (pH 9.0) containing 0.02% (w/w) alizarin red S and the Cu(II)-alizarin red complex formed was measured spectrophotometrically at 550 nm. The calibration graph for aspartame was linear in the 20-80 µg mL-1 concentration range, with a detection limit of 2 µg mL-1 of aspartame. The RSD was 0.2% for a solution containing 40 µg mL-1 aspartame (n = 10) and 70 measurements were obtained per hour. The column was stable for at least 8h of continuous use (500 injections) at 25°C. The proposed method was applied for determining aspartame in seven commercial tabletop sweeteners without interference of saccharin, acesulfame-k and cyclamate.
Aspartame Commercial product Spectrophotometry

"Performance Characteristics For Flow Injection Immunoassay Using Monoclonal Antibodies Against S-triazine And 2,4-D Herbicides"
Anal. Chim. Acta 2000 Volume 412, Issue 1-2 Pages 19-27
Milan Fránek, Anping Deng and Vladimír Kolář

Abstract: A sequential injection instrument (ALITEA, USA) with a photometric and fluorometric detection unit S2000 (Ocean Optics) was employed for the development of flow injection immunoanalysis (FIIA). The monoclonal antibodies against atrazine, simazine and 2,4-D were immobilized on aminopropyl glass particles by means of avidin/biotin system and packed in plexiglass column of 18 µl volume. Assay characteristics for individual antibody-reactors and regeneration effectivities for acid and alkaline solutions are described. An attempt to prepare a functional mixed antibody-reactor has not achieved success since regeneration conditions found for individual reactors were not compatible with one performance protocol.
Atrazine Simazine 2,4-Dichlorophenoxyacetic acid Environmental Spectrophotometry Fluorescence

"Simultaneous Determination Of Nitrate And Nitrite Ions In Seawater By Capillary Zone Electrophoresis Using Artificial Seawater As The Carrier Solution"
J. Chromatogr. A 1999 Volume 838, Issue 1-2 Pages 303-311
Keiichi Fukushi, Koji Tada, Sahori Takeda, Shin-ichi Wakida, Masataka Yamane, Kunishige Higashi and Kazuo Hiiro

Abstract: We are proposing a novel capillary zone electrophoresis for the simultaneous determination of nitrate and nitrite ions in seawater. An artificial seawater was adopted as the carrier solution to eliminate the interference of high concentrations of chloride ion etc., in seawater. For the purpose of reversing the electroosmotic Bow, 3 mM cetyltrimethylammonium chloride was added to the carrier solution. A 100 µm I.D. capillary was used to extend the optical path length. Regardless of the salinity of sample solutions, the peak areas and migration times for nitrate and nitrite ions were within±3%, while the peak heights for these ions decreased linearly with increasing salinity of sample solutions. The limits of detection for nitrate and nitrite ions were 0.04 and 0.07 mg/l (S/N=3, based on three-times the baseline noise), respectively. The values of the relative standard deviation (RSD) of peak areas for these ions were 1.5 and 2.4%. The RSDs of migration time for these ions were 0.85 and 0.78%. The proposed method was applied to the determination of nitrate and nitrite ions in seawater samples taken from the surface and the seabed. The recovery of nitrate and nitrite ions was 97-114%.

"Automated Extraction Chromatographic Separations Of Actinides Using Separation-optimized Sequential Injection Techniques"
Analyst 1999 Volume 124, Issue 8 Pages 1143-1150
Jay W. Grate, Oleg B. Egorov and Sandra K. Fiskum

Abstract: A sequential injection (SI) separation system has been developed for automated analytical separations of actinides using an actinide specific extraction chromatographic material (TRU-resin, Eichrom Industries, Inc., USA). Online liquid scintillation counting was used to observe eluting species during method development, and fraction collection and α energy analysis were used for quantification. Several procedures for individual and group actinide elution are demonstrated and discussed, including elution of actinides as a single group; elution as groups based on valence state; selective separation of Pu using on-column redox chemistry; selective separation of Th; and various sequential actinide elution schemes. Eluent solution compositions and reagent chemistries were investigated with regard to elution peak shapes, selectivity, recoveries, carryover, and suitability for rapid automated procedures. The SI separation methods described serve as the basis for an automated actinide separation work station. An automated actinide separation procedure has been applied towards the analysis of Am, Cm, and Pu isotopes in three types of aged nuclear waste samples. Results from automated analytical separations followed by quantification by α spectroscopy were in good agreement with results obtained using manual separation techniques.

"Coupling On-line Preconcentration By Ion-exchange With ETAAS. A Novel Flow Injection Approach Based On The Use Of A Renewable Microcolumn As Demonstrated For The Determination Of Nickel In Environmental And Biological Samples"
Anal. Chim. Acta 2000 Volume 424, Issue 2 Pages 223-232
Jianhua Wang and Elo Harald Hansen

Abstract: A novel way of exploiting flow injection/sequential injection (FIA/SIA) on-line ion-exchange pre-concentration with detection by electrothermal atomic absorption spectrometry (ETAAS) is described and demonstrated for the determination of trace-levels of nickel. Based on the use of a renewable microcolumn incorporated within an integrated µFI-system, the column is loaded with a defined volume of small beads of an SP Sephadex C-25 cation-exchange resin and subsequently exposed to a metered amount of sample solution. However, instead of eluting the retained analyte from the organic ion-exchange resin, the beads are along with 30 µL of carrier (buffer) solution transported via air segmentation directly into the graphite tube, where they are ashed during the pyrolysis and atomization process. The ETAAS determination is performed in parallel with the pre-concentration process of the ensuing sample. An enrichment factor of 72.1, a detection limit of 9 ng L-1, along with a sampling frequency of 12 h-1 were obtained with 150 s of sample loading time at a sample flow rate of 12 µL s-1 (corresponding to 0.72 mL min-1). The relative standard deviations were 3.4%. The procedure was validated by determination of the nickel contents in two certified reference materials and in a human urine sample.
Nickel Urine BCR 176 BCR 320 Ash River Spectrophotometry

"Comparison Of Silica-immobilized Poly(L-cysteine) And 8-hydroxyquinoline For Trace Metal Extraction And Recovery"
J. Anal. At. Spectrom. 1999 Volume 14, Issue 8 Pages 1209-1214
Maury Howard, Holly A. Jurbergs and James A. Holcombe

Abstract: Poly(L-cysteine) (PLC) and 8-hydroxyquinoline (8HQ) were immobilized on controlled-pore glass and used in a flow injection system for the separation of Cd, Pb and Cu from synthetic sea-water, Co and Ni matrices as well as CRM sea-water. Both resins allowed for the quantitative recovery of 50 µg L-1 Cd and Pb in synthetic sea-water. However, low recoveries of 2-4% and 40-50% were observed using 8HQ for the separation of 50 µg L-1 Cd and Pb, respectively, from a 10 000-fold excess of Co and Ni, while PLC maintained quantitative recoveries. Neither 8HQ nor PLC showed reproducible or complete recoveries of Cu2+ from the columns using the typical means for stripping (1 M HNO3). Online breakthrough experiments showed that 8HQ had a significant strong binding site capacity for Cd, Pb, Cu, Co and Ni. PLC also had strong sites for Cd, Pb and Cu but showed only weak binding of Co and Ni. The selectivity of PLC against these harder acid metals allowed for quantitative recovery of Cd, Pb and Cu in Co and Ni matrices. Extracting low level spikes of Cd and Pb from CRM sea-water (CASS-1 and NASS-2) tested the application to real samples. Recovery efficiencies of Cd were high for both CRM matrices studied. Pb recovery was good for CASS-1; however, recovery from NASS-2 was unexpectedly low. Mass transfer limitations were observed for both resins in the flow system, resulting in apparent decreased capacities at faster flow rates. Stability constants governing Cd adsorption by PLC and 8HQ were obtained by a non-linear least-squares regression analysis of the Cd binding data and revealed that at least four classes of binding site were present on both resins. Stability constants for the most stable sites were estimated using EDTA or ethylenediamine (en) as competing ligands. 8HQ had no sites that were competitive with EDTA, whereas PLC had an EDTA-competitive site with a stability constant of 1 x 10(13) and a capacity of 1 µmol g-1. Both PLC and 8HQ had sites that were stronger than Cd(en)(2) with estimated stability constants ranging from 10(9) to 10(11). Weaker sites on the resins had stability constants that ranged from 10(4) to 10(6). Cd was used to demonstrate the viability of this method for stability constant determination as it is well characterized for both 8HQ and PLC.

"A Simple Flow-injection On-line Clean-up System For Microwave Plasma-torch Atomic Emission Spectrometry"
Fresenius J. Anal. Chem. 2001 Volume 370, Issue 8 Pages 1061-1064
Liwei Zhao, Minjing Li, Xiaohang Xie, Daqian Song, Yuan Tian, Lijuan Zhang, Danhong Jin, Hanqi Zhang, Q. Jin

Abstract: A simple flow injection (FI) on-line clean-up system has been developed for microwave plasma-torch atomic emission spectrometry (MPT-AES). A non-selective strongly acidic cation-exchange resin was used to achieve the goal of on-line clean-up. Ag and Zr, which form halogen-complex anions in halide acid media. and Cr. Mo, and P, which exist as acid group anions or acids (neutral) in acidic solution, were determined and the interfering matrix cations were removed on-line. Satisfactory analytical results were obtained from some practical samples by use of this procedure.

"Determination Of Hydrogen Peroxide By Using A Flow Injection System With Immobilized Peroxidase And Long Pathlength Capillary Spectrophotometry"
Anal. Chim. Acta 2002 Volume 455, Issue 2 Pages 305-313
Alexandros Ch. Pappas, Constantine D. Stalikas, Yannis Ch. Fiamegos and Miltiades I. Karayannis

Abstract: The development of a highly sensitive method for the determination of nanomolar concentrations of hydrogen peroxide in the liquid phase is described. This paper demonstrates for the first time a flow injection analysis (FIA) system with immobilized enzyme reactor combined with a total internal reflective cell (a liquid waveguide capillary cell (LWCC)) and spectrophotometric detection, for the development of an improved procedure for the determination of hydrogen peroxide. Moreover, the newly synthesized 4-aminopyrazolone derivative, 4-amino-5-(p-aminophenyl)-1-methyl-2-phenyl-pyrazol-3-one (DAP), is used as a color coupler in its oxidative condensation with the sodium salt of N-ethyl-N-sulphopropylaniline sodium salt (ALPS) which acts as a hydrogen donor. Immobilization of peroxidase is achieved by coupling the periodate-treated enzyme to aminopropyl controlled-pore glass (CPG) beads. The determination of hydrogen peroxide is carried out in a 0.1 M phosphate buffer and the product is monitored at 590 nm with a charge-coupled device (CCD) detector equipped with fiber optics in a fully computerized system. The interference of different species, mainly ionic, was investigated. The method permits detection down to 4 nmol L-1 hydrogen peroxide (signal-to-noise ratio = 3). A linear calibration graph was obtained over the range 20-700 nmol L-1. The relative standard deviation (RSD) at 300 nmol L-1 H,02 is 1.7% (n = 7), The method was successfully applied for the determination of hydrogen peroxide in samples from a vat-cleaning process.

"Determination Of Nano-molar Levels Of Formaldehyde In Drinking Water Using Flow Injection System With Immobilized Formaldehyde Dehydrogenase After Off-line Solid-phase Extraction"
Anal. Chim. Acta 1999 Volume 378, Issue 1-3 Pages 169-175
Nobutoshi Kiba, Limin Sun, Shinya Yokose, Masaki Tachibana Kazue and Tani Takashi Suzuki

Abstract: Low levels of formaldehyde were determined by pre-concentration with poly(allylamine) beads and analysis by flow injection system with immobilized formaldehyde dehydrogenase. Formaldehyde dehydrogenase was immobilized on tresylate-poly(vinyl alcohol) beads and packed into a stainless-steel column (5 cm x 4 mm). The column was incorporated in a flow injection system with fluorimetic detection. The calibration graph was linear from 0.5 to 10 µM (15-300 µg l-1). The poly(allylamine) beads (0.5 g) were used to adsorb formaldehyde present at 20-400 nM (0.6-12 µg l-1) from drinking water (11). Formaldehyde was eluted with 1 M HCl (10 ml). The solution (50 µl) adjusted to pH 9 was injected into the flow injection system. Concentration factor was 25-fold. Recovery of formaldehyde spiked into purified water was >96% with a relative standard deviation of <3.0%.
Formaldehyde Water Spectrophotometry

"A Fast And Simple Turbidimetric Method For The Determination Of Sulfate In Sulfate-reducing Bacterial Cultures"
J. Microbiol. Methods 2000 Volume 41, Issue 3 Pages 179-184
&Aring;sa Kolmert, Per Wikstr&ouml;m and Kevin B. Hallberg

Abstract: A standard turbidimetric assay for the determination of sulfate in water was modified with the objective of achieving a quick and simple method for monitoring the decrease of sulfate in cultures of sulfate-reducing bacteria. The effects of sulfate concentration, mixing time and the ratio of sample to conditioning reagent were optimized using a central composite face-centered response surface model design. The results suggested that a mixing rime of 30 s resulted in smaller absorbance variance, the variance in absorbance measurements tended to increase with concentration of sulfate and that the ratio between the amount of conditioning reagent and sample had no significant influence on the absorbance variance. The modified assay thus developed is simple and quick, and covers a comparatively large sulfate concentration range (0-5 mM) compared to the standard turbidimetric assay.

"Determination Of Vanadium (V) In Drinking Water By Flow Injection And Pre-concentration In A Knotted Reactor By Inductively Coupled Plasma Optical Emission Spectrometry With Ultrasonic Nebulization"
Spectrochim. Acta B 2000 Volume 55, Issue 6 Pages 671-680
Rodolfo G. Wuilloud, Jos&eacute; A. Salonia, Roberto A. Olsina and Luis D. Martinez

Abstract: An on-line vanadium pre-concentration and determination system implemented with inductively coupled plasma optical emission spectrometry (ICP-OES) associated with a flow injection (FI) method with ultrasonic nebulization (USN) system was studied, The vanadium was retained as vanadium-2-(5-bromo-2-pyridylazo)-5-diethylaminophenol V(V)-(5-Br-PADAP) complex, at pH 3.2. The vanadium complex was removed from the knotted reactor (KR) with 30% v/v nitric acid, A sensitivity enhancement factor of 180 was obtained with respect to ICP-OES using pneumatic nebulization (15 for USN and 12 for KR). The value of detection limit for the pre-concentration of 10 mi of aqueous solution was 19 ng 1-1. The precision for 10 replicate determinations at the 5 µg L-1 V(V) level was 2.6% relative standard deviation (RSD), calculated with the peak heights obtained. The calibration graph using the pre-concentration system for vanadium was linear with a correlation coefficient of 0.9995 at levels near the detection limits up to at least 100 µg 1-1. The method was successfully applied to the determination of vanadium in drinking water samples

"Preconcentration And Speciation Of Chromium In Waters Using Solid-phase Extraction And Atomic Absorption Spectrometry"
Talanta 2000 Volume 51, Issue 3 Pages 531-536
D. M. Adri&aacute;-Cerezo, M. Llobat-Estell&eacute;s and A. R. Maur&iacute;-Aucejo

Abstract: A method for the pre-concentration and speciation of chromium was developed. After formation of an anionic compound with ethylenediaminetetraacetic acid (CrY-), Cr (VI) and Cr (III) are retained on a strong anionic phase (SAX) and controlled elution with 0.5 M NaCl permits their speciation. The retention and elution conditions were optimized, and interferences due to the presence of other ions such as Mg(II), Mn(lI), Sn(II), Fe(III), Ba(II), Al(III), Ca(II), chloride, iodine, bromide, fluoride, sulfate, phosphate, bicarbonate and nitrate were studied. The detection limits were 0.4 µg L-1 and 1.1 µg L-1 for Cr(III) and Cr(VI), respectively, and reproducibility was 9%. The results obtained for speciation of chromium by the proposed method in wastewaters are in agreement with the values obtained by a reference method for a 95% confidence level.
Chromium(III) Chromium(VI) Waste Spectrophotometry

"Lead Determination With On-line Enrichment System"
Water Res. 2000 Volume 34, Issue 17 Pages 4215-4219
Krystyna Pyrzynska and Mihaela Cheregi

Abstract: The flow injection pre-concentration system with a cellulose sorbent was developed to determine trace; mounts of lead. The metal was pre-concentrated on a microcolumn packed with Cellex P, cellulose sorbent with phosphonic acid groups, and eluted with nitric acid into the nebuliser-burner system of atomic absorption spectrometer. An enrichment factor of 47-197, equivalent of 5.1-25.5 mL of sample, was achieved by using time-based system. The detection limit (3 delta) for 1 min pre-concentration time was 1.8 µg L-1 and precision (at 10 µg L-1 level) was 7.8% (RSD). The method was applied to the determination of lead in natural water samples.
Lead River Spectrophotometry

"Plant Tissue-based Chemiluminescence Flow Biosensor For Urea"
Anal. Chim. Acta 2000 Volume 407, Issue 1-2 Pages 81-86
Wei Qin, Zhujun Zhang and Youyuan Peng

Abstract: A novel plant tissue-based chemiluminescence (CL) biosensor for urea combined with flow injection analysis is proposed in this paper. The analytical reagents involved in the CL reaction, including luminol and permanganate, were both immobilized on anion exchange resin columns, while the biological material soybean tissue was packed in a mini-glass column. By the urease-catalyzed reaction in the plant tissue column, urea was hydrolyzed to NH4+ and HCO3-. The anion produced could release luminol from the anion-exchange column with immobilized luminol, which then reacted with permanganate eluted from the anion-exchange permaganate column with sodium hydroxide, thus producing a CL signal. The CL emission intensity was linear with urea concentration in the range 4-400 µM; the detection limit was 2 µM. Interfering ions co-existing in urine could be effectively separated on-line by an ion-exchange column placed upstream. The biosensor was applied successfully to the analysis of urea in urine samples.
Urea Urine Sensor

"Sequential Injection Flow System With Improved Sample Throughput: Determination Of Glycerol And Ethanol In Wines"
Anal. Chim. Acta 2002 Volume 458, Issue 1 Pages 131-138
Marcela A. Segundo and Ant&oacute;nio O. S. S. Rangel

Abstract: The performance of sequential injection (SI) systems has often been criticized for its low sampling frequency. The present work describes a SI system where an injection valve and an additional pump were incorporated to enhance sample throughput rate. The proposed system was applied to the enzymatic determination of glycerol and ethanol in wines, using spectrophotometric detection and immobilized glycerol and alcohol dehydrogenases. The method proposed was applied to the determination of ethanol between 0.10 and 0.50% (v/v) and glycerol between 0.03 and 0.30 g L-1. These ranges were appropriate for determination in table and port wines, since samples were diluted 50 times before introduction into the system. The results obtained from 15 wine samples were statistically comparable to those obtained by the reference methods, with good repeatability (RSD < 3.4%, n = 10). The sampling rate was 22.5 hr-1, corresponding to 45 determinations per hour. This way, the time required for each determination was decreased by 30% when compared to a conventional SI system.

"An Online Solid Phase Extraction System Using Polyurethane Foam For The Spectrophotometric Determination Of Nickel In Silicates And Alloys"
Anal. Chim. Acta 1999 Volume 378, Issue 1-3 Pages 287-292
S&eacute;rgio Luis Costa Ferreira, Djane Santiago de Jesus, Ricardo Jorgensen Cassella, Antonio Celso Spinola Costa, Marcelo Souza de Carvalho and Ricardo Erthal Santelli

Abstract: The present paper describes the use of a solid phase extraction system using a polyurethane foam (PUF) minicolumn, in order to separate nickel from interferences due to other elements and determine it by flow injection analysis with spectrophotometric detection. Separation is based on the retention of thiocyanate complexes of interferent ions in the PUF minicolumn. Nickel does not form complex with thiocyanate and pass through the minicolumn and then it can be determined by using 4-(2-pyridylazo)-resorcinol (PAR) as chromogenic reagent. So, parameters such as thiocyanate concentration and pH effects on the separation efficiency, sorption capacity of the polyurethane foam minicolumn, influence of the flow rates, PAR concentration, pH effect on the chromogenic reaction, minicolumn regeneration, analytical features and others were investigated. The results demonstrated that nickel (at concentration of 0.5 mg/ml) can be quantitatively separated from iron and copper (200 mg/ml), zinc and cobalt (100 mg/ml) by using a minicolumn containing 0.125 g of polyurethane foam. Nickel can be determined with great selectivity and sensitivity and the procedure was applied for nickel determination in brass, bronze, steel and rock certified reference materials. The results showed satisfactory accuracy and precision. The limit of detection was 77 ng/ml and the RSD was 2.63%. A dynamic range from 0.25 up to 5.00 µg/ml and a sample throughput of 24 samples per hour were achieved.
Nickel Alloy Alloy Alloy Alloy Geological Spectrophotometry

"Amperometric Enzymatic Detection Of Phenols For HPLC"
Chem. Anal. 2000 Volume 45, Issue 5 Pages 667-679
M. Szewczynska and M. Trojanowicz

Abstract: Tyrosinase, laccase and coconut tissue were compared as active biocomponents in enzymatic detection of phenols. The obtained selectivity of biocatalytic activity of tyrosinase was found to be dependent on the way of enzyme immobilization. The measurements were carried out in flow injection systems with flow-through reactors and carbon paste based integrated biosensors. For the use as a detector in a HPLC system the tyrosinase carbon paste bio sensor was found to be the most convenient. The obtained detection limits were 0.072, 0.037 and 0.032 mg L-1 for hydroquinone, phenol and catechol, respectively.

"FIA-FAAS System Including On-line Solid Phase Extraction For The Determination Of Palladium, Platinum And Rhodium In Alloys And Ores"
Talanta 2000 Volume 52, Issue 1 Pages 39-50
I. A. Kovalev, L. V. Bogacheva, G. I. Tsysin, A. A. Formanovsky and Yu. A. Zolotov

Abstract: A number of aliphatic mono- and triamines have been investigated as potential reagents for solid phase extraction of Rh, Pd and Pt. Platinum group metals are recovered from hydrochloric acid solutions as ionic associates of their chloride complexes with protonated amines. The recovery of metals depends both on hydrophobic properties of amine and sorbent and on sorption behavior of amine itself. For on-line solid phase extraction of platinum group metals 4-(n-octyl)diethylenetriamine and hyper cross-linked polystyrene sorbent SSPS have been applied. Quantitative recovery of rhodium and platinum in the form of their hexachloride complexes was achieved under non-equilibrium conditions of on-line dilution. Metals recovered are quantitatively eluted with 1 M hydrochloric acid solution in ethanol. A new FIA-FAAS method for the determination of Rh, Pd and Pt in solutions based on the decomposition of ores and alloys has been proposed. The RSD values are 0.03-0.08 at 50-ppb concentration level. The detection limits are 3-8 ppb for 1 min of pre-concentration. The accuracy of the procedure was verified by the analysis of standard reference materials of sulfide ores and alloys.

"A Continuous Spectrophotometric System For The Discrimination/determination Of Monosaccharides And Oligosaccharides In Foods"
Anal. Chim. Acta 2000 Volume 404, Issue 1 Pages 121-129
A. C&aacute;ceres, S. C&aacute;rdenas, M. Gallego and M. Valc&aacute;rcel

Abstract: A simple, rapid method for the spectrophotometric discrimination of monosaccharides from the oligosaccharide fraction of fruit juice, jam, syrup and honey samples is proposed. The sample, in alkaline medium, is directly introduced into a flow system and passed through an activated carbon column for its decolorization; then, a volume of 200 µl is injected into the derivatising reagent stream to start the analytical reaction, which takes place at 85°C. The two fractions are discriminated on the basis of the different colors of the derivatives formed; thus, the derivatives of the monosaccharides are yellow while those of the di- and trisaccharides are violet-carmine. The two fractions are monitored at 400 and 540 nm, respectively. Sucrose gives no reaction as it is a non-reducing sugar. The proposed method allows reducing sugars contents from 0.01% to 0.80% w/v to be determined with an average relative standard deviation of 4.5% and a sampling frequency of 10 h-1. The proposed method was validated by applying it to two milk-based and sugar candidate artificial CRMs, with good correlation. The detection limits achieved (0.01% w/v for maltose, lactose and maltotriose at 540 nm) allow adulteration of fruit juices with high fructose syrup from starch at the 4% level to be detected.
Monosaccharides Oligosaccharides Maltose Lactose Maltotriose Fruit Food Food Food Spectrophotometry

"An Improved Technique For The Determination Of Oxidised Nitrogen In Natural Waters With A Sequential Injection Analysis (SIA) System"
Water SA 2001 Volume 27, Issue 3 Pages 355-360
EB Naidoo and JF van Staden

Abstract: An SIA systems proposed for the determination of oxidized nitrogen (nitrate + nitrite as N) in natural waters. A cadmium reductor, made of cadmium granules, closely packed in a glass column reduces the nitrate to nitrite. The reduced nitrate and the nitrite present in the water samples is diazotised in the SIA system with sulphanilamide and coupled with N - (1-napthyl) ethylene diammoniumdichloride to form a highly colored azo dye which is detected at 540 nm with a UV/Vis spectrophotometer. The proposed system is fully computerised and is able to monitor total oxidized nitrogen as nitrite at a frequency of 36 samples per hour with a standard deviation of < 1.2%, The calibration curve is linear up to 5 mg/l with a detection limit of 0.01 mg/l.
Nitrate Nitrite Environmental Spectrophotometry

"Flow Injection Method For The Determination Of Serine Using Immobilized Enzyme"
Talanta 2001 Volume 55, Issue 6 Pages 1181-1186
M. Yaqoob and A. Nabi

Abstract: A flow injection method for the determination of serine using a mini-column containing immobilized serine dehydratase isolated and purified from rat liver is described. Ammonia produced from the enzymatic reaction is coupled with hypochlorite and phenol in an alkaline medium yields a blue product due to the indophenol anion formation, which is the basis of a spectrophotometric detection at 640 nm. The limit of detection (2 x blank noise) is 0.01 mM with a sample throughput of 25 h-1. Calibration graph is linear in the range 0.2-1.0 mM, with relative standard deviation 0.6-1.0%. (C) 2001 Elsevier Science B.V. All rights reserved.

"Chemiluminescence Flow Biosensor For Determination Of Total D-amino Acid In Serum With Immobilized Reagents"
Sens. Actuat. B 2000 Volume 69, Issue 1-2 Pages 70-74
Baoxin Li and Zhujun Zhang

Abstract: A flow injection chemiluminescence (CL) biosensor for the determination of total D-amino acid is described in this paper. D-amino acid oxidase was immobilized onto amine-modified silicagel via glutaraldehyde activation and packed in a column. The other analytical reagents, including luminol and ferricyanide, were electrostatically co-immobilized on an anion-exchange column. D-amino acid was sensed by the CL reaction between hydrogen peroxide produced from the enzyme column and luminol and ferricyanide, which were eluted from the ion-exchange column through sodium phosphate injection. The linear range of D-alanine concentration is 1.1 X 10^-6 to 1.1 X 10^-4 mol/l and the detection limit was 4.5 X 10^-7 mol/l (3s). The proposed method has been successfully applied to the determination of D-amino acid in human serum.

"Preconcentration And Determination Of Trace Chromium(III) By Flow Injection Inductively-coupled Plasma Atomic Emission Spectrometry"
Anal. Chim. Acta 1986 Volume 179, Issue 1 Pages 487-490
Alan G. Cox and Cameron W. McLeod

Abstract: The method previously described [Analyst (London), 1985, 110, 331] is modified by use of the alumina column in basic instead of acidic form and is applied to human urine. The Cr is adsorbed from the sample in 0.02 M NH3 as carrier and is eluted with 2 M HNO3. The response is rectilinear from 10 to 1000 µg L-1 with a limit of detection of 0.92 µg L-1 and a coefficient of variation for 10 µg L-1 of 12% (n = 10). For a standard urine reference sample of certified value of 0.085 ± 0.006 µg mL-1, a result of 0.079 ± 0.004 µg mL-1 has been obtained (n = 10).
Chromium(III) Urine Clinical analysis Spectrophotometry

"Flow Injection Determination Of Iron(II), Iron(III), And Total Iron With Chemiluminescence Detection"
Anal. Chim. Acta 1986 Volume 184, Issue 1 Pages 311-315
E. G. Sarantonis and Alan Townshend

Abstract: The determination of Fe(II) (1 nM to 1 µM) was carried out by the production of chemiluminescence from 5 mM luminol solution, with no added oxidants, in a flow injection chemiluminescence analyzer.. Tervalent Fe (20 nM to 2 µM) was determined after acidification with 0.01 M HCl and reduction to Fe(II) in a silver reductor mini-column in the flow system. Calibration graphs were rectilinear over the above ranges, with detection limits of 0.5 nM and 20 nM for Fe(II) and Fe(III), respectively; coefficient of variation were <3%. Cobalt, Cr, Cu and Mn interfered.
Iron(2+) Iron(III) Iron Chemiluminescence

"Flow Injection Determination Of Adenosine And Inosine In Blood Plasma With Immobilized Enzyme Columns Connected In Series And Fluorimetric Detection"
Anal. Chim. Acta 1986 Volume 186, Issue 1 Pages 131-137
Yohji Hayashi, Kiyoshi Zaitsu and Yosuke Ohkura

Abstract: Samples were mixed with HClO4, and centrifuged, the supernatant solution was treated with K2CO3 followed by centrifugation, and urate oxidase and catalase, were added to the supernatant solution. After 30 min at 37°C, the solution was treated as above, the supernatant solution was diluted with Tris - HCl buffer of pH 8.0 and an aliquot was analyzed on successive columns (4 cm x 0.86 mm) of adenosine deaminase, purine nucleoside phosphorylase, xanthine oxidase, urate oxidase and horse-radish peroxidase, immobilized on amino-derivatized controlled-pore glass AMP-CPG 1400 (120 to 200 mesh; 140 nm pore size). The carrier and reagent solution contained 0.15 M NaCl - 50 mM Na2HPO4 - 10 mM Na2EDTA and 0.1 M Tris - HCl buffer (pH 8.0); the reagent solution also contains 5 mM 3-(4-hydroxyphenyl)propionic acid(I),flow rates were 0.25 mL min-1, and the H2O2 formed was detected fluorimetrically after reaction with I at 405 nm (excitation at 305 nm). Calibration graphs were rectilinear from 0.5 to 500 pmol of adenosine or inosine, with recoveries of ~100% and coefficient of variation of 1% (n = 10).
Adenosine Inosine Blood Plasma Clinical analysis Fluorescence

"Fluorimetric Determination Of Nitrate In Natural Waters With 3-amino-1,5-naphthalenedisulfonic Acid In A Flow Injection System"
Anal. Chim. Acta 1987 Volume 193, Issue 1 Pages 343-347
Shoji Motomizu, Hiroshi Mikasa and Kyoji T&ocirc;ei

Abstract: The sample (160 µL) was injected into a carrier stream containing 1 mM EDTA, 50 mM NaCl and water (pH 8.1 to 8.4) and the solution was passed through a copperized cadmium column to reduce the NO3- to NO2-. The solution was then mixed with a stream containing 2 M HCl, 1 mM EDTA and 3-aminonaphthalene-1,5-disulfonic acid (0.3 mM or 30 µM) at 90°C. The azoic acid derivative produced was determined by mixing this stream with aqueous 20% NaOH and measuring the fluorescence at 470 nm (excitation at 365 nm). The flow rate of each stream was 0.7 mL min-1. Calibration graphs were rectilinear for up to 0.2 mM NO3-; the detection limit was ~1 nM-NO3-. In the determination of 20 µM-NO3-, the coefficient of variation was 0.8% (n = 10). Most cations and anions commonly found in natural waters did not interfere. Results for river and seawater samples agreed with those obtained by ion chromatography.
Nitrate River Sea Fluorescence

"Sensitive Flow Injection Determination Of L-lactate In Human Blood With Immobilized Enzyme Columns And Fluorimetric Detection"
Anal. Chim. Acta 1987 Volume 201, Issue 1 Pages 351-355
Kiyoshi Zaitsu, Masao Nakayama and Yosuke Ohkura

Abstract: The sample is deproteinized and the supernatant solution in 10 mM imidazole - HCl carrier solution of pH 7.0 is passed through two columns, the first packed with L-lactate oxidase and the second with horse-radish peroxidase on glass beads. The H2O2 produced in the first column is mixed with 3-(4-hydroxyphenyl)propionic acid before entry into the second column and measurement of the fluorescence at 415 nm (excitation at 320 nm). The response is rectilinear up to 500 pmol with a limit of determination of 0.5 pmol (20 µL injection). The recoveries are ~100% for 1 to 10 mM lactate with coefficient of variation (n = 10) of 1.4 and 0.97% for 0.83 and 3.9 mM, respectively.
Lactate Whole Human Fluorescence

"Lead Preconcentration With Flow Injection For Flame Atomic Absorption Spectrometry"
Anal. Chim. Acta 1988 Volume 214, Issue 1-2 Pages 329-337
S. R. Bysouth and J. F. Tyson, P. B. Stockwell

Abstract: Three flow injection manifolds were evaluated for the cited determination. The manifolds each involved a column containing, e.g., quinolin-8-ol material, an autosampler and an AAS detector. Elution was with HCl. Timed sample loading and matrix removal without passing the matrix to the nebulizer were achieved with one valve, but reagent consumption and calibration time were reduced by incorporating further valves. The effects of pH and interfering ions were studied. Water samples from lead pipes were analyzed by using a 2-valve manifold, a column packed with 2-methylquinolin-8-ol and direct neblization. Detection limits down to 1.4 ng mL-1 were achieved.
Lead Water Spectrophotometry

"Sorbent Extraction In Flow Injection Analysis And Its Application To Enhancement Of Atomic Spectrometry"
Anal. Chim. Acta 1989 Volume 216, Issue 1-2 Pages 243-255
J. Ruzicka and A. Arndal

Abstract: Standard Cu(II) and Pb(II) solution were prepared from the respective nitrates in 0.1 M HNO3. A time-based injection and a fixed-volume system are described and illustrated. The sample was mixed with a 0.05% solution of Na diethyldithiocarbamate (I) in 0.01 M acetic acid - aqueous 0.02 M NH3 (pH 9.2) containing 0.1% of Na2S2O4, and the solution was passed through a column (6.5 mm x 5 mm) containing 100 mg of Bond-Elut C18, with methanol as eluent. Lead and Cu were determined by AAS at 283.3 and 324.8 nm, respectively. Alternatively, saturated quinolin-8-ol (II) solution in 0.01 M acetic acid - aqueous 0.02 M NH3 (pH 9.2) was used as reagent solution and the eluent was ethanol. Complexation with 1-(2-pyridylazo)-2-naphthol and 4-(2-pyridylazo)resorcinol was also possible. Detection limits were 0.01 mg L-1 for Pb and 4 µg L-1 for Cu by using I and II, respectively. Standard Cu(II) and Pb(II) solution were prepared from the respective nitrates in 0.1 M HNO3. A time-based injection and a fixed-volume system are described and illustrated. The sample was mixed with a 0.05% solution of Na diethyldithiocarbamate (I) in 0.01 M acetic acid - aqueous 0.02 M NH3 (pH 9.2) containing 0.1% of Na2S2O4, and the solution was passed through a column (6.5 mm x 5 mm) containing 100 mg of Bond-Elut C18, with methanol as eluent. Lead and Cu were determined by AAS at 283.3 and 324.8 nm, respectively. Alternatively, saturated quinolin-8-ol (II) solution in 0.01 M acetic acid - aqueous 0.02 M NH3 (pH 9.2) was used as reagent solution and the eluent was ethanol. Complexation with 1-(2-pyridylazo)-2-naphthol and 4-(2-pyridylazo)resorcinol was also possible. Detection limits were 0.01 mg L-1 for Pb and 4 µg L-1 for Cu by using I and II, respectively.
Copper Lead Spectrophotometry Sample preparation

"Determination Of Trace Manganese In High-purity Titanium, Silicon And Mineral Acids By A Flow Injection Method Based On A Catalytic Reaction"
Anal. Chim. Acta 1989 Volume 217, Issue 1 Pages 23-30
Chongliang Zhang, Susumu Kawakubo and Tsutomu Fukasawa

Abstract: Sample solution (1 to 2 ml; 1.5 M in HF and 0.2 M in HCl) was subjected to ion-exchange extraction on a column of Amberlite CG-120 (H+ form, 100 to 200 mesh), with elution of the Mn with 6 M HCl. The eluate was evaporated almost to dryness, and the residue was dissolved in acetate buffer (pH 4.4). Portions (100 µL) were injected into the flow injection system where they were mixed with reagent solution [0.26 mM malachite green (C. I. Basic Green 4) - 0.01 M KIO4] before passing to a reaction coil at 50°C. The absorbance of the solution was measured at 615 nm. The calibration graph was rectilinear for up to 7 ng of Mn and the coefficient of variation (n = 5) at 3 ng of Mn was 2%. The method was successfully applied in the analysis of HF, HCl and HNO3 and of Ti metals and Si (sample prep. described).
Manganese Inorganic compound Inorganic compound Inorganic compound Metal Metal Spectrophotometry

"Flow Injection Determination Of Branched-chain L-amino-acids With Immobilized Leucine Dehydrogenase"
Anal. Chim. Acta 1989 Volume 218, Issue 1 Pages 161-166
Nobutoshi Kiba, Sachie Hori and Motohisa Furusawa

Abstract: Leucine dehydrogenase was immobilized on polystyrene Bio-Beads in a stainless-steel column (10 cm x 4 mm) and the column was incorporated into a flow system for determination of L-leucine, L-isoleucine and L-valine. A solution of 10 mM NAD+ in 1 mM Na4 EDTA was mixed with buffer solution (glycine - KCl - KOH of pH 11) before injection of the sample. The solution then passed to the enzyme reactor (thermostatted at 40°C) and the NADH produced was monitored fluorimetrically at 465 nm (excitation at 340 nm). The calibration graph was rectilinear from 5 µM to 0.5 mM isoleucine. The detection limit for L-leucine was 1 µM. The method was applied in the analysis of serum.
l-Leucine l-Isoleucine l-Valine Blood Serum Fluorescence

"Flow Injection System With Ion-exchange Separation And Potentiometric Detection For The Determination Of Three Halides"
Anal. Chim. Acta 1989 Volume 219, Issue 1 Pages 55-65
Jacobus F. van Staden

Abstract: Halides were separated on a column (8 cm x 2.8 mm) of Dowex 1-XB (NO3 - form; 100 to 200 mesh) incorporated in a flow injection system fitted with a tubular Ag - silver halide ion-selective electrode as potentiometric sensor. Injected samples (30 µL) were mixed in a coil (105 cm x 0.51 mm) with the carrier stream (0.1 M KNO3) at a flow rate of 3.9 mL min-1. Chloride, Br- and I- were eluted in that order from the anion-exchange column. Then, 0.5 M KNO3 was added to the eluate at a flow rate of 1.4 mL min-1 , and after further mixing in a coil (1.6 m x 0.51 mm), the potential was measured. Calibration graphs were rectilinear from 20 to 5000 mg L-1 for single and mixed halide solution The detection limit was 5 µg l-1.
Chloride Bromide Iodide Potentiometry Electrode

"Trace Metal Enrichment By Automated Online Column Preconcentration For Flow Injection Atomic Absorption Spectrometry"
Anal. Chim. Acta 1989 Volume 221, Issue 1 Pages 65-76
Shizuko Hirata, Kazuto Honda, Takahiro Kumamaru

Abstract: Trace metals were pre-concentrated on a micro-column (7 mm x 4 mm) of Muromac A-1 (50 to 100 mesh) at a flow rate of 5 mL min-1. Ions were eluted with 2 M HNO3 (4.85 mL min-1), before analysis by flame AAS. Optimum pH was established for metal ion uptake from sample solution The coefficient of variation for 20 mL samples containing 5 to 100 µg L-1 of Cd, Cr, Cu, Fe, Mn, Pb or Zn were 0.7 to 1.7% (n = 3 or 4). Values for Cd and Cr in standard reference materials of plants, mussel tissue and pond sediment were within the specified range.
Cadmium Chromium Copper Iron Manganese Lead Mussel Pond Spectrophotometry

"Flow Injection Determination Of L-tyrosine In Serum With An Immobilized Tyrosinase Reactor And Fluorescence Detection"
Anal. Chim. Acta 1989 Volume 224, Issue 1 Pages 133-138
Nobutoshi Kiba, Masae Ogi and Motohisa Furusawa

Abstract: Serum (100 µL) was deproteinized with Na2WO4 - H2SO4 and filtered, and 50 µL of the filtrate was injected into a carrier stream of 0.3 M phosphate buffer of pH 7.2 (0.6 mL min-1), which passed through a separation column (5 cm x 4 mm) of Capcell 120 C18 (5 µm) and a reactor column (5 cm x 4 mm) containing the cited enzyme immobilized on controlled-pore glass beads and was then mixed with a stream of 5 M KOH (1 mL min-1). The fluorescence was measured at 490 nm (excitation at 375 nm). The calibration graph was rectilinear in the range 0.1 µM to 0.1 mM tyrosine, the detection limit was 50 nM, and the coefficient of variation (n = 10) for the determination of 5.0 µM-tyrosine was 2.0%.
Tyrosine Blood Serum Fluorescence

"Determination Of Total 3α-hydroxy-bile Acids In Serum By A Bioluminescent Flow Injection System Using A Hollow-fibre Reactor"
Anal. Chim. Acta 1989 Volume 225, Issue 2 Pages 273-282
Kayoko Oda, Shigeru Yoshida and Shingo Hirose, Tatsumori Takeda

Abstract: A bacterial luciferase and NADH-flavin mononucleotide oxidoreductase were covalently co-immobilized on CNBr-activated Sepharose 4B. A permeable membrane reactor was used to introduce NAD+ and the bioluminescent reagent [comprising flavin mononucleotide, dithiothreitol and decanal in phosphate buffer (pH 6.8)]. The column, filled with the immobilized bioluminescent enzyme, was placed in front of a photomultiplier tube inside a photon counter to give a continuous-flow light-emitting system which was versatile and simple. The membrane reactor flow injection system allowed >20 samples h-1 to be analyzed. The detection limit was 10 fmol of NADH for a 1 µL injection. The calibration graphs for Na cholate were rectilinear up to 10 µM and 5 to100 µM. Excellent reproducibility, precision and sensitivity were achieved. Results agreed with those obtained by fluorimetry.
Bile acids, 3-α hydroxy Cholate Blood Serum Bioluminescence

"Flow Injection Immunoassays With Acridinium Ester-based Chemiluminescence Detection"
Anal. Chim. Acta 1989 Volume 227, Issue 1 Pages 97-107
C. Shellum and G. G&uuml;bitz

Abstract: The cited method was demonstrated by determination of mouse IgG. Anti-mouse IgG was labelled with acridinium N-hydroxysuccinimide ester and immobilized on a column of Trisacryl GF-2000. Samples (20 µL) of IgG, labelled IgG and a mixture of H2O2 and NaOH solution were consecutively injected into a buffered carrier stream to the column and the emitted light was measured with a Kratos fluorimeter. The response was rectilinear up to 20 fmol with a limit of detection of 0.2 fmol. The coefficient of variation (n = 10) were 4.3%.
Immunoglobulin G Immunoassay Chemiluminescence

"Determination Of Copper(II) In A Complex Matrix After Prereduction To Copper(I) In A Flow Injection System With An Amperometric Detector"
Anal. Chim. Acta 1990 Volume 228, Issue 1 Pages 117-122
Mouna Noufi, Ch. Yarnitzky and Magda Ariel

Abstract: A flow injection manifold and an amperometric detector equipped with a carbon-paste electrode in a wall-jet type configuration were used to determine Cu in complex media at +0.050 V vs. Ag - AgCl. Both the reduction current peak of Cu(II) and the oxidation peak of Cu(I) (obtained in the presence of hydroxylamine in the reagent stream) were proportional to the Cu(II) concentration. in the original sample. Acidified Cu(II) samples containing additional Fe(II), Zn, Pb(II) and relatively high concentration. of serum albumin were analyzed by using a chelating column to retain the heavy metal ions, while allowing albumin to run to waste. The retained metals were subsequently eluted with HNO3 into a stream of Na acetate or Na acetate - hydroxylamine. The oxidation (hydroxylamine) system was preferred as it gave the best sensitivity and reproducibility, minimum Fe interference and an electrode surface which remained uncontaminated and stable throughout the analytical run. Sample throughput was 25 h-1. The method was applied to the determination of Cu in standard human blood serum.
Copper(II) Serum Human Amperometry Electrochemical analysis Electrode Electrode

"Rapid Flow Injection Sandwich-type Immunoassays Of Proteins Using An Immobilized Antibody Reactor And Adenosine Deaminase-antibody Conjugates"
Anal. Chim. Acta 1990 Volume 229, Issue 1 Pages 47-55
I. H. Lee and M. E. Meyerhoff

Abstract: Human IgG (I) and α1-acid glycoprotein (II) were determined in biological samples in a flow injection assay cycle involving sequential injection of sample and adenosine deaminase - antibody conjugate (goat anti-I or rabbit anti-II antibodies for I and II, respectively) into a 0.025 M Tris - HCl (pH 7.5) carrier buffer. Bound antibody - analyte was retained on a column (2.5 cm x 1.54 mm) of goat anti-I or rabbit anti-II antibodies immobilized on controlled-pore glass beads. Substrate (0.25 mM adenosine in 0.5 M Tris - HCl of pH 7.5) was then fed into the reactor and the eluate was monitored by NH4+-selective potentiometry. Between steps a wash stream of 0.1 M glycine - HCl (pH 2.2) was used. Working ranges were from 5 to 400 ng mL-1 of I and 3 to 15 µg mL-1 of II. Results for I agreed well with those by several commercially available methods and recoveries were 102 to 107%. Analysis time was ~12 min.
Protein Biological Immunoassay Potentiometry

"Determination Of Uranium Using A Flow System With Reagent Injection. Application To The Determination Of Uranium In Ore Leachates"
Anal. Chim. Acta 1990 Volume 230, Issue 1 Pages 217-220
J. L. Perez Pavon, B. Moreno Cordero, E. Rodriguez Garcia and Hernandez Mendez

Abstract: A flow injection spectrophotometric system is described in which UO22+ in the sample stream is reduced by passage through a glass column (5 cm x 2 mm) packed with Pb powder (0.1 to 0.3 mm) to U(IV), which then reacts with an injection of 0.2 mM arsenazo III in 3.6 M HCl containing 1% of Triton X-100 to form a complex for absorbance measurement at 665 nm. The detection limit is 26 nM-U, and the coefficient of variation (n = 10) at 6 µM was 0.62%. Zirconium can be masked with oxalic acid, and of 19 other species tested only Th interferes; this interference can be overcome by incorporating a valve to by-pass the reducing column and measuring the difference in peak heights with and without reduction.
Uranium Leachate

"Flow Injection Extraction-spectrophotometric Method For The Determination Of Lead And Its Combination With Minicolumn Preconcentration"
Anal. Chim. Acta 1990 Volume 230, Issue 1 Pages 157-162
E. A. Novikov, L. K. Shpigun and Yu. A. Zolotov

Abstract: Two flow injection systems were devised, one without and one with ion-exchange pre-concentration. [2-mm-i.d. glass column of Chelex-100 resin (NH4+ form; 50 to 100 mesh)]. The Pb(II) was extracted from an aqueous HNO3 carrier stream into dicyclohexano-18-crown-6 solution in CHCl3 in a PTFE coil (2 m x 0.5 mm), and after phase separation in a membrane separator the CHCl3 layer was treated with 0.002% dithizone - 0.4% triethanolamine solution in CHCl3 (mixing ratio 3:2) in a 30-cm PTFE reaction coil for absorbance measurement at 512 nm. With ion-exchange pre-concentration. for 79 s, the calibration graph was rectilinear in the range 10 to 200 µg l-1, the detection limit was 5 µg L-1 and the coefficient of variation at 100 µg L-1 was 9% (n = 4). Test applications to analyzes of alloys, soil extracts and seawater are described briefly.
Lead Sea Environmental Alloy Ion exchange Spectrophotometry Sample preparation

"Flow Injection Spectrophotometric Determination Of Acetyl-coenzyme A With Immobilized Phosphotransacetylase"
Anal. Chim. Acta 1990 Volume 232, Issue 1 Pages 281-286
Susumu Yamato and Kenji Shimada

Abstract: A method is given for immobilizing phosphotransacetylase on AF-Tresyl TOYOPEARL 650 gel. The treated gel, suspended in 0.1 M phosphate buffer, (pH 8) containing 1 mM NaN3, was packed in stainless-steel columns (1 cm x 4 mm), which were stored at 4°C. The carrier stream for flow injection analysis contained 30 mM Na2HPO4, 15 mM (NH4)2SO4 and Ellman reagent in 0.1 M borate buffer of pH 7.5 (1 mL min-1). Samples (25 µL) were injected into the carrier stream, which then passed through the gel column at 40°C In the reaction, acetyl coenzyme A was converted into acetyl phosphate and the free mercapto-compound reacted with Ellman reagent; the yellow color was detected at 412 nm. Calibration graphs were rectilinear from 4 µM to 0.4 mM, with a detection limit of 0.8 µM. At 0.2 mM, the coefficient of variation (n = 27) was 1.7%. The column was stable for 2 months, comprising ~1000 analyzes.
Acetyl-CoA Spectrophotometry

"Flow Injection Technique For The Determination Of Low-levels Of Phosphorus In Natural Waters"
Anal. Chim. Acta 1990 Volume 234, Issue 2 Pages 409-416
Paul R. Freeman, Ian D. McKelvie and Barry T. Hart, Terence J. Cardwell

Abstract: A flow injection instrument for determining low concentration. of P in waters is described and illustrated. The main feature is the use of an inexpensive detector consisting of a flow cell and a photometer that incorporates a super-bright red-light emitting diode as the source and a photodiode as the detector. The procedure is a modification of the tin(II) chloride - molybdate method (cf. Tecator Application Note ASN 60-01183, Tecator AB, 1983) optimized by a modified simplex optimization method. Silicate interference (5 mg mL-1) was removed by addition of aqueous 0.1% tartaric acid. The calibration graph was rectilinear up to 100 µg L-1 of P and the detection limit was 0.6 µg l-1. The coefficient of variation were 2.9% and 0.5% for 2.0 and 50 µgl-1 of P, respectively. An inline pre-concentration anion-exchange column was used to obtain a lower detection limit of 0.1 µg l-1.
Phosphorus Environmental Spectrophotometry

"Indirect Flow Injection Determination Of Methadone By Atomic Absorption Spectrometry"
Anal. Chim. Acta 1990 Volume 234, Issue 2 Pages 433-437
R. Montero, M. Gallego and M. Valc&aacute;rcel

Abstract: Methadone (I) is determined in tablets and urine in the presence of other drugs after reduction on a Cd or Zn micro-column and flame AAS detection of the metal ions released. For urine, a 5 mL sample is made alkaline with NaOH and extracted with CH2Cl2. The residue from evaporation of the extract, is dissolved in water, and the solution is adjusted to pH 4.0 with 0.01 M acetic acid. Crushed tablet (200 mg) is dissolved in water by shaking for 55 min and filtering. The final solution (90 µL), at pH 3.3 to 4.3, is injected into a carrier stream of water (3.0 mL min-1) which proceeds to the reduction column (8.5 cm x 1.8 mm) and subsequently to the spectrometer. The calibration graph is rectilinear from 5 to 50 ng mL-1 of I. Recoveries from either column are quantitative, and coefficient of variation in urine (n = 3) are 1.2 to 3.0%. Sampling frequency is 150 h-1, and other drugs do not interfere.
Methadone Pharmaceutical Urine Spectrophotometry Sample preparation

"Online Continuous-flow Extraction System In Liquid Chromatography With Ultraviolet And Mass Spectrometric Detection For The Determination Of Selected Organic Pollutants"
Anal. Chim. Acta 1990 Volume 234, Issue 1 Pages 119-126
A. Farran, J. L. Cortina and J. de Pablo, D. Barcel&oacute;

Abstract: A system is described which allows UV detection and MS characterization of ng amounts of pesticides in water. It involves completely continuous-flow analysis, with extraction with heptane, a PTFE membrane separator, separation on a column of Spherisorb ODS, and detection at 220 nm and by MS. Extraction varied from 60% (for organophosphorus pesticides and the degradation product 2,4,5-trichlorophenol) to 100% for chlorophenoxy acids, except for the degradation product 4-nitrophenol (10%). The limit of detection was 200 to 400 pg with UV detection. Tetrachlorvinphos was determined in a spiked river water at 1 mg L-1 by MS with selected-ion monitoring.
Pesticides Tetrachlorvinphos 2,4,5-Trichlorophenol River LC Mass spectrometry Sample preparation

"Automated Method For The Determination Of Boron In Water By Flow Injection Analysis With Inline Preconcentration And Spectrophotometric Detection"
Anal. Chim. Acta 1990 Volume 234, Issue 1 Pages 199-206
I. Sekerka and J. F. Lechner

Abstract: The system (schematically presented) involved pre-concentration. of B from a sample by ion-exchange on a column of Amberlite IRA-743, elution with a stream of azomethine-H in 2 M ammonium phosphate buffer (pH 6.6) containing EDTA, and detection of the B complex at 420 nm. Full operating details are given. Online pre-concentration. was carried out for 3 or 6 min for 10 or 10 µg L-1 of B, respectively. Recoveries were 96 to 101%. The coefficient of variation were 10% for 10 µg L-1 and 5% for 10 to 200 µg l-1. The detection limit was 1 µg l-1, with a sampling rate of 10 h-1. The method was applied to natural- and tap-water. Results show good agreement with those of ICP-AES. There was no interference, even for colored samples.
Boron Environmental Water Ion exchange Spectrophotometry

"Flow Injection Determination Of Paraoxon By Inhibition Of Immobilized Acetylcholinesterase"
Anal. Chim. Acta 1990 Volume 236, Issue 2 Pages 267-272
M. E. Leon-Gonzalez and Alan Townshend

Abstract: A system incorporating two injection valves and a spectrophotometric detector (operated at 500 nm) is described and illustrated. The sample solution is injected into a stream of 0.05 M phosphate buffer (pH 8.0) containing 45 mM NaCl and 12 µM-MgCl2. A solution (0.3 mM) of 1-naphthyl acetate, as substrate, is injected via the second valve into the middle of the paraoxon zone. The resulting stream is passed through a glass column, maintained at 29°C, containing acetylcholinesterase immobilized (method described) on controlled-porosity glass (80 to 120 mesh; mean pore diameter 22.6 nm) and is then merged with a solution (5 mM) of p-nitrobenzenediazonium fluoroborate to react with the liberated naphthol before reaching the detector. Continuous-flow and stopped-flow versions of the method are described; in the latter, the sample and substrate are stopped for 35 s in the column. Rectilinear ranges of the continuous- and stopped-flow procedures are 0.2 to 15 µM and 10 to 400 nM, respectively; corresponding detection limits and sample throughput are 0.4 µM and 60 h-1, and 8 nM and 30 h-1. The coefficient of variation (n = 6) for the respective procedures were 1.4% at 8 µM and 0.9% at 0.25 µM. Optimization of the method is described.
Paraoxon Spectrophotometry

"Determination Of Cobalt(II), Copper(II) And Iron(II) By Ion Chromatography With Chemiluminescence Detection"
Anal. Chim. Acta 1990 Volume 236, Issue 2 Pages 287-292
Bolei Yan and Paul J. Worsfold

Abstract: Optimum conditions for the separate flow injection determination of Cu(II), Co(II), Fe(II) and Cr(III) comprised water as carrier stream, a reagent of 50 µM-luminol and 5 mM H2O2 in 0.1 M carbonate buffer of pH 11.7, and a flow rate of 1.5 mL min-1 per channel. Separation of the metals was achieved by ion chromatography on a column (25 cm x 4.6 mm) of Partisil 10 SCX, with an aqueous solution of a carboxylic acid as mobile phase (1.5 mL min-1). Complex formation between the carboxylic acid and the metal suppressed the chemiluminescence in the subsequent luminol - H2O2 reaction; however, oxalic acid (5 mM) caused only a 14% suppressive effect for 100 ng mL-1 of Cu(II) and gave good separation of Cu(II), Co(II) and Fe(II); 5 mM oxalic acid at pH 4.2 was thus used as mobile phase. Detection limits by ion chromatography were 0.01 and 5 ng mL-1 for Co and Cu, respectively; those by flow injection analysis were 0.6 pg mL-1 for Co, 80 pg mL-1 for Cu, 0.3 ng mL-1 for Fe(II) and 0.1 ng mL-1 for Cr(III).
Cobalt(II) Copper(II) Iron(2+) Chemiluminescence

"Determination Of Chromium By Online Preconcentration On A Poly (hydroxamic Acid) Resin An Flow Injection Atomic Absorption Spectrometry"
Anal. Chim. Acta 1990 Volume 236, Issue 2 Pages 469-473
Ajay Shah and Surekha Devi

Abstract: Seven poly(hydroxamic acid) resins [Analyst (London), 1985, 110, 501] were evaluated for LC separation of Cr(III) from U(VI) and from multi-component mixtures. Columns (17 cm x 5 mm) containing the resins in H+ form were used, and the flow rate for sorption and elution was 1 mL min-1. At pH 5, U(VI), Fe(III), Zn and Cu(II) were retained on the resin, but ~80% of the Cr(III) passed through. Retained U(VI) was eluted by 1 M HCl, Zn and Cu(II) by 0.1 M HCl and Fe(III) by 3 M HCl. Cross-contamination was observed between Zn and Cu. Tervalent Cr could also be determined by flow injection flame AAS with use of a column (4 cm x 2.5 mm) of poly(hydroxamic acid) resin and a carrier stream of 0.2 M acetate buffer (pH 2) for pre-concentration.; the Cr(III) was then eluted with 1 M HCl for AAS at 357.9 nm. The calibration graph was rectilinear for 10 µL portions of solution containing 20 to 100 ng mL-1 of Cr(III). The flow injection method was used to determine Cr(III) in seawater at pM concentration.
Chromium Sea Spectrophotometry

"Flow Injection System For The Fluorimetric Determination Of Fructose With An Immobilized Mannitol Dehydrogenase Reactor"
Anal. Chim. Acta 1991 Volume 243, Issue 2 Pages 183-186
Nobutoshi Kiba, Yukari Inoue and Motohisa Furusawa

Abstract: Sample solution was injected into a carrier stream of water (0.5 mL min-1), which was merged with 10, 100 or 200 µM-NADH in 0.2 M phosphate buffer (pH 7.0; 0.5 mL min-1) for reaction in a reaction column (5 cm x 4 mm) of mannitol dehydrogenase immobilized on poly(vinyl alcohol) beads (prep. described) at 40°C. The decrease in NADH was monitored fluorimetrically at 465 nm (excitation at 340 nm). Calibration graphs were rectilinear for 3 to 30, 15 to 150 or 60 to 600 µM-fructose (I) for 10, 50 and 200 µM-NADH, respectively; the detection limit was 1 µM-I for 10 µM-NADH. Seventeen carbohydrates did not interfere; D-mannitol did interfere. The sampling rate was 30 h-1. The column retained >80% of its activity after continuous use over 2 months. The method was applied in the determination of I in fruit juice, wine and cola.
Fructose Wine Fruit Soft drink Fluorescence

"Determination Of Trace Levels Of Sulfate In Water Using Flow Injection And Inline Preconcentration"
Anal. Chim. Acta 1991 Volume 244, Issue 1 Pages 109-113
M. Karlsson, J. -&Aring;A. Persson and J. M&ouml;ller

Abstract: A fully automated flow injection analysis system is described for the determination of SO42- in water. Sample is first passed through an enrichment column of Bio-Rad AG1-X8 resin (100 to 200 mesh) in the sample loop of the injector. This also separates SO42- from divalent cations that might interfere in the determination step. The sulfate is eluted into the system with 0.3 M NaCl and mixed with a stream of methyl thymol blue reagent (pH 2.5) followed by a stream of 0.05 M NaCl (details given). Sulfate is determined from its effect on the complexation of methyl thymol blue with Ba. Detection is at 620 nm. The detection limit was 25 µg L-1 of SO42- and the calibration graph was rectilinear from 25 to 1000 µg l-1; the coefficient of variation was 1.5%. A wash cycle could be introduced to reduce interference from high levels of divalent cations; the tolerance limit for phosphate was ~1 to 5 mg l-1.
Sulfate Water

"Flow Injection Determination Of D-mannitol With Immobilized Mannitol Dehydrogenase"
Anal. Chim. Acta 1991 Volume 244, Issue 1 Pages 105-107
Nobutoshi Kiba, Yukari Inoue and Motohisa Furusawa

Abstract: In the flow injection method described (diagram of apparatus given), 5 mM NAD+ was mixed with 0.2 M carbonate buffer of pH 10.0 (total flow-rate 0.5 mL min-1) and passed through a mixing coil (1 m x 0.5 mm). Sample solution (50 µL) was injected into the stream, the mixture was passed through a column reactor (5 cm x 4 mm) containing mannitol dehydrogenase immobilized on poly(vinyl alcohol) beads (cf., Ibid., 1991, 243, 183) at 37°C and the NADH produced was detected fluorimetrically at 465 nm (excitation at 340 nm). The calibration graph was rectilinear for 0.5 to 100 µM-D-mannitol and the detection limit was 0.1 µM. The sampling rate was 30 h-1 and the coefficient of variation (n = 12) was 1%. The method was applied in the analysis of celery juice and chewing gum (prep. described); results compared well with those by a chromatographic method. The method should also be applicable to biological samples.
d-Mannitol Juice Food Fluorescence

"Determination Of Gold In Ore By Flame Atomic Absorption Spectrometry With Flow Injection Online Sorbent Extraction Preconcentration"
Anal. Chim. Acta 1991 Volume 245, Issue 1 Pages 7-11
Shukun Xu, Lijing Sun and Zhaolun Fang

Abstract: A section of plastic Eppendorf pipette tip, measuring 0.6 and 5.0 mm i.d. at the lower and upper ends, respectively, was packed tightly (~2 cm) with Amberlite XAD-8 resin (25 to 50 mesh) (~220 µL). The column was fitted in the flow injection manifold such that adsorbed complexes were collected mainly at the narrower end and eluted from the broader to the narrower end. Samples (10 g) were heated (570°C, 30 min) in a muffle and then digested (50 min) in boiling 1:1 aqua regia (80 ml). After evaporation almost to dryness, concentrated HCl (10 ml) was added and brought to the boil. After cooling, the leachate and undissolved residue were made up to 250 mL with water. The complexes formed were adsorbed on the XAD-8 resin (7.6 mL min-1) and, after 40 s, adsorbed analyte was eluted with aqueous 95% ethanol (3.6 mL min-1) into the nebulizer and flame for determination by AAS (242.8 nm). The calibration graph was rectilinear up to 0.5 µg mL-1 and the detection limit was 2 ng mL-1 in the leachate, corresponding to 0.05 mg kg-1 in the ore. The coefficient of variation (n = 11) was 1.4% at 0.25 µg mL-1 for a single digest solution; the overall coefficient of variation was 3 to 5%. Recoveries of known amounts added to samples were 97 to 107%. The sampling rate was 60 h-1.
Gold Geological Sample preparation Spectrophotometry Sample preparation

"Flow Injection Spectrophotometric Determination Of Chloride With An Online Solid Mercury(II) Thiocyanate Mini-column And Bromide With A Silver Thiocyanate Mini-column"
Anal. Chim. Acta 1991 Volume 245, Issue 1 Pages 115-119
Ala'ddin M. Almuaibed and Alan Townshend

Abstract: Mini-columns were packed with Hg(SCN)2 (4 cm x 0.25 mm) or AgSCN (3 cm x 0.25 mm) and incorporated into flow injection systems. Chloride solution (60 µL) were injected into a stream (1.4 mL min-1) of 0.05 M HNO3 and passed through the Hg(SCN)2 column. After merging with a stream (1.4 mL min-1) of 0.12 M Fe(III) and reaction in a coil of length 35 cm, the absorbance was measured at 465 nm. The calibration graph was rectilinear over the range 28 µM to 0.85 mM Cl-, and the limit of detection was 5.5 µM (23.4 ng in 120 µL). The coefficient of variation for ten replicate injections of 0.28 mM Cl- was 1.0%. The sampling rate was 100 h-1 and the column lifetime was 50 injections. The system for the determination of Br- differed only in the use of the AgSCN column, a sample volume of 80 µL and a reaction coil length of 40 cm. The calibration graph was rectilinear over the range 38 µM to 0.24 mM Br- and the limit of detection was 10 µM (64 ng in 80 µL). The coefficient of variation for ten replicate injections of 0.19 mM Br- was 1.0%. The sampling rate was 100 h-1 and the column lifetime was at least 200 injections.
Bromide Chloride Spectrophotometry

"Flow Injection Radio-release Analysis For Vanadium"
Anal. Chim. Acta 1991 Volume 246, Issue 2 Pages 329-331
Kate Grudpan and Duangjai Nacapricha

Abstract: The system consisted of a peristaltic pump that delivered the carrier solution (1.2 mL min-1) to a micro-column packed with 110 mAg powder; the packed column was shielded with lead. Acetate buffer solution (pH 3) was used as carrier solution Standard V solution (0.5 to 0.7 ml) was injected into the carrier stream and transported into the micro-column; the released radioactive Ag+ was detected by means of a flow-through coil mounted within a well-type NaI(Tl) detector. The detection limit was 10 µg mL-1 of V; calibration graphs were rectilinear up to 100 µg mL-1.
Vanadium

"Online Preconcentration And Determination Of Trace Elements By Flow Injection Inductively Coupled Plasma Atomic-emission Spectrometry"
Anal. Chim. Acta 1991 Volume 248, Issue 1 Pages 241-249
S. Caroli, A. Alimonti and F. Petrucci, Zs. Horv&aacute;th

Abstract: Columns (5 cm x 2 mm) of iminodiacetic acid - ethylcellulose chelating resin (I; 100 to 200 mesh) were used to pre-concentrate trace elements in a computer-assisted online flow injection analysis - ICP-AES technique. Elements of clinical and environmental importance (Cd, Co, Cu and Pb) in water, seawater and urine were determined. A 4-way rotary valve assembly was used to fill the column with solution (mixed with 2 M acetate buffer, pH 5.5), elute the analytes with 2 M HNO3, push the eluent plug with a countercurrent flow of water carrier to the excitation source and wash the column. Sample throughput was 10 to 12 h-1. Compared with pre-concentration. on carboxymethylated polyethyleneimine - polymethylenephenylene isocyanate and Chelex 100 resins, the online mode using I gave a 2- to 4-fold improvement in detection limits and a reduced column volume of about a fifth. Detection power is improved at least one order of magnitude for Cd and Pb in seawater.
Cadmium Cobalt Copper Lead Urine Water Sea Spectrophotometry

"Flow Injection ELISA For Process Monitoring And Control"
Anal. Chim. Acta 1991 Volume 249, Issue 1 Pages 163-168
Mats Nilsson, H&aring;kan H&aring;kanson and Bo Mattiasson

Abstract: A fully automated competitive flow injection ELISA is described (with diagrams). The flow system is computer-controlled and its operation involves mixing of sample and labelled antigen solution, passing of this mixture through a column containing immobilized antibodies, application of substrate solution at the column, spectrophotometric detection and column reconditioning with buffer solution The system was evaluated with the determination of IgG with a protein A - sepharose column and horse-radish peroxidase-labelled rabbit anti-human IgG.
Immunoglobulin G Spectrophotometry

"Post-column Liquid Chromatographic Method For The Determination Of Cyanide With Fluorimetric Detection"
Anal. Chim. Acta 1991 Volume 251, Issue 1-2 Pages 255-259
Keiji Gamoh*, Senya Imamichi

Abstract: Cyanide ions were separated from other ions by ion-exclusion HPLC on a Shim-pack SCR-102H column operated at 40°C with 10 mM HClO4 as mobile phase (1 mL min-1). Column eluate was mixed at 40°C with 2 mM phthalaldehyde (OPA) or naphthalenedicarboxaldehyde (NDA) and 20% ethanolic 0.5 mM Na4 EDTA in carbonate - borate buffer solution and then with 2 mM amino acid and 0.5 mM Na4 EDTA in carbonate-borate buffer. Fluorimetric detection was at 400 nm (excitation at 330 nm) for CN- - OPA derivatives or at 490 nm (excitation at 420 nm) for CN- - NDA derivatives. Use of NDA gave the best sensitivity. The calibration graph was rectilinear from 0.5 µg L-1 to 2 mg L-1 of CN-. The detection limit was ~0.1 µg l-1. The coefficient of variation (n = 10) were 1.4% at 10 µg L-1 and 3.1% at 0.5 µg l-1.
Cyanide HPLC Fluorescence

"Determination Of The Fluorescent Drugs Dipyridamole And Benzydamine In Rat Plasma By Liquid Chromatography With Peroxyoxalate Chemiluminescence Detection"
Anal. Chim. Acta 1991 Volume 251, Issue 1-2 Pages 247-253
Atsuhiko Nishitani, Yukie Tsukamoto, Susumu Kanda and Kazuhiro Imai*

Abstract: Plasma (10 µL) or, for dipyridamole (I) determination, plasma diluted 10-fold with 150 mM imidazole buffer solution (pH 6.0) was mixed with imidazole buffer solution (40 µL; as above), internal standard solution (20 µL) and acetonitrile (130 µL) and the mixture was centrifuged at 2500 g for 5 min. The internal standards were 5-(NN-dimethylaminonaphthalene)-1-sulfonyl-L-phenylalanine for I and I for benzydamine hydrochloride (II). Sample solution was injected into a flow system (described with diagram) containing a column (15 cm x 4.6 mm) of TSK ODS 8OTm (5 µm) operated at 40°C with 50 mM imidazole buffer (pH 6.0) - acetonitrile (1:1) as eluent. The eluate was mixed with 0.25 mM bis-[4-nitro-2-(3,6,9-trioxadecyloxycarbonyl)phenyl]oxalate and 12.5 mM H2O2 solution in acetonitrile - ethyl acetate (1:1) before detection of chemiluminescence. Calibration graphs were rectilinear from 2.5 to 200 nM-I and 2.5 to 100 µM-II. Detection limits were 345 pM-I and 147 nM-II.
Benzydamine Dipyridamole Plasma Rat Chemiluminescence LC

"Detection Of Some Sulfur Anions And Colloidal Sulfur By Flame Molecular-emission Spectrometry"
Anal. Chim. Acta 1991 Volume 251, Issue 1-2 Pages 197-203
Sverre Hauge and Kjartan Mar&oslash;y, Arngr&iacute;mur Thorlacius*

Abstract: The flow injection system previously described (Ibid., 1991, 243, 227) for SO42- was applied to determine S-containing anions. The system incorporated a Dowex 50W-X8 cation exchange column (H+ form; 20 to 50 mesh). Emission efficiencies relative to SO42- were calculated and the chemiluminescence process and ammonium interference are discussed. The ammonium enhanced intensity by ~30%. Detection limits were 0.1 to 0.8 mg L-1 of S.
Sulfur Chemiluminescence Spectrophotometry

"Polyaniline Chemically-modified Electrode For Detection Of Anions In Flow Injection Analysis And Ion Chromatography"
Anal. Chim. Acta 1991 Volume 252, Issue 1-2 Pages 53-57
Erkang Wang* and Anhua Liu

Abstract: A film of polyaniline was electrochemically deposited on a glassy carbon electrode (c.f., Ye and Baldwin, Anal. Chem., 1988, 60, 1979). With the electrode in FIA the maximum response for NO3-, I-, SCN-, Br-, SO42-, ClO4-, acetate and oxalate was at +0.4 V vs. SCE for 0.2 M acetate buffer eluent (pH 3.8), and at +0.6 V for 0.2 M boric acid (pH 5.2) or NaNO3 (pH 5.7). For ion chromatography the detector was used with a column of AS1 and a mobile phase of 0.06 M NaNO3 at 1.5 mL min-1. The calibration graphs for I-, Br-, SCN- and S2O32- were rectilinear from 2 to 100, 8 to 100, 15 to 100 and 15 to 100 mg L-1 with detection limits of 1, 5, 10 and 10 mg l-1, respectively. With FIA the range extended over >3 orders of magnitude with a detection limit for I- and ClO4- of 0.1 mg l-1.
Anions Iodide Perchlorate HPIC Electrode Electrode

"Flow Injection Atomic Spectrometric Determination Of Inorganic Arsenic(III) And Arsenic(V) Species By Use Of An Aluminum-column Arsine Generator And Cold-trapping Arsine Collection"
Anal. Chim. Acta 1992 Volume 261, Issue 1-2 Pages 105-113
M. Burguera, J. L. Burguera and M. R. Brunetto, M. de la Guardia and A. Salvador

Abstract: The sample is injected into water as carrier and the solution (with or without introduction of 10% KI solution to reduce As(V)) is mixed with 5 M NaOH before passage through an electrically heated Pyrex column containing a rolled foil of metallic Al (~1 g) to reduce As(III) to AsH3. The AsH3 passes to a gas - liquid separator and is collected for 3 min in a liquid-N-cooled trap. The trap is then placed in hot water, and He is used to sweep the AsH3 into a fused-silica cell above an air - acetylene flame for AAS measurement at 193.7 nm. Analysis for As(III) and total As takes ~10 min. Optimized operating conditions are given. Interference in the determination of 1 ng of As(III) was caused by >10 ng of Ni, Be, Cr(III), Ag, Pb, Cu(II), Sn, Zr, or Fe(III). The detection limit was 0.25 µg L-1 of As(III) or As(V). The method was successfully applied to water samples from a trout fishery. A flow injection system is described for the selective determination of arsenic(III) and arsenic(V) (0.05-20 ng) in a 100 µL sample volume by hydride generation and atomic absorption spectrometry. An elec. heated aluminum column was used to generate the arsine in an alkaline medium. Recoveries averaged 97-99% for arsenic(III) and 95-98% for arsenic(V) with relative standard deviations of less than 4.3% in each instance. The detection limit was 0.25 µg L-1 (25 pg) of arsenic in both instances. This method was relatively free from interferences and was applied successfully to the determination of arsenic(III) and arsenic(V) in trout fishery water samples. The data obtained were compared with those produced by a hydride generation-cold trapping atomic absorption spectrometric detection method, using sodium tetrahydroborate(III) in hydrochloric acid. The results obtained by both methods were in close agreement, within 96-102%.
Arsenic(3+) Arsenic(5+) Arsenic, inorganic Water Spectrophotometry Spectrophotometry

"Coupled Flow Injection Analysis - Flame-atomic Absorption Spectrometry For The Quantitative Determination Of Aluminum In Beverages And Waters Incorporating Online Cation-exchange"
Anal. Chim. Acta 1992 Volume 269, Issue 1 Pages 1-7
Henryk J. Salacinski, Philip G. Riby, Stephen J. Haswell*

Abstract: Tea leaf samples (0.5 g) were digested at 85°C for 45 min in a mixture of HNO3 (4 ml) and HClO4 (1 ml) and diluted to 10 mL with 5% HNO3. Samples of tea and coffee infusions and water were acidified with 5% HNO3. These samples (250 µL) were injected via a loop into a SCX preparative column (500 mg) with water as the carrier, followed by elution with 4 M HCl (250 µL) directly into the nebulizer of a flame AAS for the determination of Al. The AAS and nebulizer were optimized for max. absorbance prior to the determination and the peristaltic pump of the flow system set to give an equivalent delivery. Rectilinear calibrations were obtained from 0.07 to 6.45 µg mL-1 of Al from various timed depositions with a coefficient of variation of 1.1% and a detection limit of 75 ng mL-1. A method for determining the aluminum levels in local water, tea leaf digest, tea and coffee infusions by means of online cation exchange flow injection - flame atomic absorption spectrometry (FIA-FAAS) is described. Quant. results can be carried out down to 75 ng mL-1 of Al using sample volumes in the range 6.0-24.0 mL. The method using a conventional FAAS system was found to be rapid, simple and relatively inexpensive offering good selectivity and typical relative standard deviation of 1-2% (n=10) with a relative error of about 2%.
Aluminum Environmental Leaves Tea Coffee Ion exchange Sample preparation Sample preparation Spectrophotometry

"Determination Of L-glutamate And L-glutamine By Flow Injection Analysis And Chemiluminescence Detection: Comparison Of An Enzyme Column And Enzyme Membrane Sensor"
Anal. Chim. Acta 1993 Volume 271, Issue 2 Pages 231-237
Gert Blankenstein, Frank Preuschoff, Uwe Spohn and Karl-Heinz Mohr, Maria-Regina Kula*

Abstract: L-Glutamate and L-glutamine were determined by luminol chemiluminescence with flow injection analysis. Glutamate oxidase and glutaminase were co-immobilized on controlled-poreglass (CPG) for the determination of glutamate and glutamine. The hydrogen peroxide produced by enzymatic degradation was detected by luminol chemiluminescence catalyzed by peroxidase either immobilized on CPG or on a pre-activated membrane. Arthromyces ramosus peroxidase produced a much stronger luminescence signal than horseradish peroxidase. Immobilization of the microbial peroxidase on a membrane inside the flow cell simplified the technique. The membrane sensor had a detection limit of 0.1 µM-L-glutamate and 1 µM-L-glutamine. The calibration graph was rectilinear for 0.1 to 60 µM-L-glutamate and 1 µM to 2.5 mM L-glutamine.
l-Glutamate l-Glutamine Chemiluminescence Sensor

"Flow Injection Sample Preparation For Organotin Speciation Analysis Of Water By Capillary Gas Chromatography - Microwave Induced Plasma Atomic-emission Spectrometry"
Anal. Chim. Acta 1993 Volume 278, Issue 1 Pages 99-113
Joanna Szpunar-obiska, Michiel Ceulemans, Ryszard obiski and Freddy C. Adams*

Abstract: A semi-automatic flow injection system is described for online sample preparation for the determination of mono-, di-, tributyl- and triphenyltin compounds in river water. The organotin compounds were extracted from 10^-50 mL of acidified water (pH 2) by adsorption onto a C18 micro-column, derivatized with sodium tetraethylborate and eluted with 250 µL of methanol containing tetrabutyltin as an internal standard. Portions of the eluate (25 µL) were analyzed by GC-AES with a temperature programmed cooled injection system which allowed the solvent to be vented off while the higher boiling point organotin compounds were transfered onto a column (25 m x 0.32 mm) coated with HP-1 (0.17 µm), operated with temperature programming from 45°C (held for 2 min) to 280°C at 20°C/min. Calibration graphs were rectilinear for 0-100 ng/l of the organotin compounds but there was a different response factor for each analyte due to the non-quantitative recovery of mono-substituted organotins. Detection limits were 0.1-0.17 ng/l with RSD (n = 5) of 4.3-9.2%.
Monobutyltin Dibutyltin Tributyltin Triphenyltin River GC Spectrophotometry Sample preparation

"Off-line And Online Preconcentration Of Trace Levels Of Beryllium Using Complexing Agents With Atomic-spectrometric And Fluorimetric Detection"
Anal. Chim. Acta 1993 Volume 283, Issue 2 Pages 909-915
D. B. Do Nascimento and G. Schwedt

Abstract: Two methods were investigated. The first method used polyethylene powder as an adsorbent for the pre-concentration of the stable complex formed between Be and Chrome azural S (CAS; C. I. Mordant Blue 29) followed by analysis by graphite-furnace AAS (GF-AAS). The sample solution was adjusted to pH 3 with HCl and treated with 0.5 M succinic acid buffer solution of pH 4.5 and 6% aqueous CAS. The mixture was passed (0.5 ml/min) through the pre-concentration column containing polyethylene powder. After washing the column with water and drying in air, the Be-CAS complex was eluted with ethanol (0.4 ml/min). The eluate were analyzed by GF-AAS at 239.4 nm, with Ar purge gas (temp. programming details given). The method was used to determine Be in tap water. The detection limit was 0.8 µg/l of Be and the RSD were 2.5-4.1%. Recoveries were 92-104%. The second method (details given) used an ion-exchange micro-column in a FIA system for the pre-concentration of Be, which was reacted with morin and detected by fluorescence. The method was also used to determine Be in tap water. The detection limit was 0.2 µg/l of Be and the RSD was ~1.5%. Recoveries were 95-105%.
Beryllium Water Ion exchange Fluorescence Spectrophotometry

"Chemiluminescent Flow Sensor For The Determination Of Paraoxon And Aldicarb Pesticides"
Anal. Chim. Acta 1994 Volume 294, Issue 1 Pages 35-42
Aldo Roda, Pavel Rauch, Elida Ferri, Stefano Girotti*, Severino Ghini, Giacomo Carrea and Roberto Bovara

Abstract: Aldicarb (I); 60 µL containing up to 100 µg/ml of I or paraoxon (II) also containing 5 mM acetylcholine and electric-eel acetylcholinesterase (III) at 20 miu in Tris hydrochloride of pH 8/DMSO was injected into a stream of phosphate buffer of pH 8 (0.1 ml/min) and merged with the chemiluminescent reagent (0.2 ml/min) of 56 µM-luminol in 0.2 M Tris hydrochloride of pH 8 and fed through a packed column (3 cm x 2 mm i.d.) of choline oxidase/peroxidase (16:1) immobilized on Eupergit C which was sited in front of the photomultiplier tube of the luminometer. With operation at a flow that enabled an incubation time of 1 h, the detection limits were 4 µg/l for I and 0.75 µg/l for II (RSD, n = 10, 6.6 and 3.8%, respectively) and a throughput of up to 15 samples/h was possible. Loading of III in solution enabled much improved detection limits, relative to immobilization of III on the Eupergit C column.
Aldicarb Paraoxon Commercial product Chemiluminescence Sensor

"Determination Of Trace Metals In Natural Waters By Flame Atomic Absorption Spectrometry Following On-line Ion-exchange Preconcentration"
Anal. Chim. Acta 1995 Volume 303, Issue 2-3 Pages 341-345
M. C. Yebra-Biurrun, A. Bermejo-Barrera, M. P. Bermejo-Barrera* and M. C. Barciela-Alonso

Abstract: An on-line column pre-concentration technique for flow-injection flame atomic absorption spectrometry has been developed for the determination of trace metals in natural waters. A minicolumn (20 mm x 2 mm i.d.) filled with a poly(aminophosphonic acid) chelating resin (PAPhA, 20-30 mesh) was used for the pre-concentration procedure. For 2 mL samples, detection limits of 0.5, 5.0, 1.5, 1.6, 3.5, 0.6, 3.2, 3.1 and 0.4 g 1-1 for Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb and Zn, respectively, were achieved. The precision (coefficient of variation) obtained was in the range between 1.1 (Cd and Cu) and 3.3% (Co). Accuracy was also investigated and results agreed with the certified values of the reference material. The sampling rate was 48 h-1. The method was applied to the determination of trace metals in natural waters samples from Galicia (Spain).
Cadmium Cobalt Chromium Copper Iron Manganese Nickel Lead Zinc Environmental Ion exchange Spectrophotometry

"Automatic Implementation Of The Method Of Standard Additions In Unsegmented Flow Systems"
Anal. Chim. Acta 1995 Volume 308, Issue 1-3 Pages 77-84
Manuel Agudo, Angel R&iacute;os and Miguel Valc&aacute;rcel*

Abstract: A flow system was described for the preparation of sample and standard solutions for calibration by the method of standard additions. The system allowed variable volumes of both sample and standard solution added to a carrier. After homogenizing, a portion was injected into the FIA manifold for analysis. The methodology was applied to the determination of glucose and fructose in various types of drinks using various immobilized enzymes. The combined concentration of glucose and fructose was obtained by reaction with adenosine-5-triphosphate and β-NADP+ in the presence of the immobilized enzymes hexokinase, phosphoglucose isomerase (PGI) and glucose-6-phosphate dihydrogenase. The NADPH formed was monitored at 340 nm. Glucose was determined by omitting PGI from the enzyme column which enable fructose to be calculated by difference. Glucose and fructose were determined in the ranges 0.01-0.1 g/l and 0.02-0.1 g/l, respectively, and the RSD was ±0.8% for 0.05 g/l glucose and ±1% for 0.07 g/l fructose. The analysis of drinks yielded average errors of 3.8% for glucose and 4.6% for fructose.
Fructose Glucose Beverage Spectrophotometry

"Sequential Enzymic Monitoring Of Glucose, Ethanol And Glutamate In Bioreactor Fermentation Broth Containing A High Salt Concentration By A Multi-channel Flow Injection Analysis Method"
Anal. Chim. Acta 1995 Volume 308, Issue 1-3 Pages 145-151
Richie L. C. Chen and Kiyoshi Matsumoto*

Abstract: An automated glucose analyzer. was modified to form a multichannel FIA system for the sequential determination of glucose, ethanol and glutamate. The modifications consisted of inserting a computer controlled column switching valve downstream from the injector. Each channel was equipped with a mini-reactor column containing immobilized glucose oxidase, alcohol oxidase or glutamate oxidase. The product from the enzyme reactions, H2O2, was detected electrochemically. The carrier solution (3 ml/min) was 0.1 M phosphate buffer of pH 6.8 and the injection volume was 2 µL for each determination. The apparatus was evaluated by monitoring the fermentation of a fish sauce with Torulopsis versatiles immobilized beads. Due to the high salt concentration in the fermentation broth it was necessary to insert a Dowex 1-X8 anion-exchange column between the injector and the column switching valve to eliminate the interference of NaCl. Linear calibration graphs were obtained for 0.5-5% (w/v) glucose and ethanol and 0.1-2% (w/v) glutamate. The results were confirmed by analysis with assay kits.
Ethanol Glucose Glutamate Fermentation broth Electrochemical analysis

"Online Coated Columns For The Spectrophotometric Determination Of Metals By Continuous-flow Analysis"
Anal. Chim. Acta 1995 Volume 308, Issue 1-3 Pages 378-385
Yuri A. Zolotov, Irina M. Maksimova, Elena I. Morosanova* and Andrei A. Velikorodny

Abstract: Online coated microcolumns and capillary tubes were evaluated for the separation and pre-concentration of metal ions by continuous-flow analysis. Xylenol orange, 1-(2'-pyridylazo)-2-naphthol and (p-sulfophenylazo)-2'-sulfo-4'-nitrodiazoaminobenzene disodium salt (Cadion) were immobilized on reversed-phase silica (C16, C8, phenyl, C1) packed into microcolumns (2.5 cm x 2 mm i.d.) or on capillary tubes (10 m x 2 mm i.d.) with hydrophobic inner surfaces (C6, C-phenol, C1). The optimum conditions for the maximum retention of reagent were determined. The adsorption and acid desorption of metal ions from coated microcolumns and capillaries were studied and procedures for the determination of Cd, Co, Cu and Fe(III) in the range 0.08-30 µM were suggested using spectrophotometric detection. Preconcentration factors of up to 9 and 19 were achieved with coated microcolumns and capillaries, respectively.
Cadmium Cobalt Copper Iron(III) Spectrophotometry

"Spectrophotometric Determination Of Total Phenolics By Solvent Extraction And Sorbent Extraction Optosensing Using Flow Injection Methodology"
Anal. Chim. Acta 1995 Volume 310, Issue 3 Pages 437-446
Wolfgang Frenzel* and Stephanie Krekler

Abstract: The method was based on the reaction of phenols with 4-aminoantipyrine (4-AAP). The reaction product was concentrated by (i) solvent extraction into CHCl3, or (ii) sorbent extraction using a C18-modified silica microcolumn. For i, sample was injected into a water carrier stream (2.8 ml/min) which merged with reagent streams (R1 and R2; 0.4 ml/min) containing 0.4 g/l 4-AAP of pH 10.2 and 0.1% potassium hexacyanoferrate(III) of pH 4, respectively, and was extracted with CHCl3 (0.6 ml/min). After passing though a phase separator the absorbance of the organic phase was measured at 460 nm. The calibration graph for phenol was linear for 0.02-0.5 mg/l, the detection limit was 8 µg/l and the RSD were 5%. For ii, a sample stream (2.6 ml/min) was merged with reagent streams R1 and R2 (0.6 ml/min; half the concentrations given above), passed through the microcolumn (3 cm x 2 mm i.d.) for 2 min and the imine product was eluted with methanol and detected at 460 nm. The calibration graph was linear for 0.02-500 mg/l phenol and the detection limit was 11 µg/l. Detection by oncolumn optosensing was also investigated using a Si microcolumn mounted in a light-emitting diode-based spectrophotometer with the first 3 mm of the sorbent illuminated (details given).
Phenols, total Spectrophotometry Sample preparation

"Graphite-poly(tetrafluoriethylene) Electrodes As Electrochemical Detectors In Flowing Systems"
Anal. Chim. Acta 1995 Volume 314, Issue 1-2 Pages 13-22
C. Fern&aacute;ndez, A. J. Reviejo and J. M. Pingarr&oacute;n*

Abstract: Graphite/PTFE composite electrodes (details given) were used as indicator electrodes for the flow injection amperometric detection of the herbicides, thiram (I) and disulfiram (II) at a potential of +1 V vs. Ag/AgCl/3 M KCl in a carrier stream (1.9 ml/min) of 0.1 M phosphate buffer at pH 7.4 and with an injection volume of 250 µL. Calibration graphs were linear up to 40 µM-I and -II and the detection limits were 0.043 and 0.02 µM, respectively. RSD (n = 10) were 7.7 and 5.7%, respectively, for 0.1 µM of I and II. Recoveries of 40 µg/l of I from spiked tap and well water were >97%. The adsorptive pre-concentration of the herbicides from flowing streams (2.7 ml/min) was carried out at 0.0 V. At the end of the pre-concentration period the phosphate buffer stream was passed for 30 s prior to the determination of the suface-bound herbicide by applying a linear sweep anodic potential ramp up to +1.2 V. Calibration graphs were linear from 0.4-1 and 0.2-1 µM-I and -II, respectively. The continuous-flow injection separation of I and II was carried out by inserting a 30-40 µm VYDAC SC-201 column (3 cm x 0.2 mm i.d.) into the FIA system and using acetonitrile/0.1 M phosphate buffer at pH 7.4 (1:3) as mobile phase (1.9 ml/min).
Disulfiram Thiram Water Well Amperometry Electrode

"Determination Of Uranium In Tin Tailing Using 4-(2-pyridylazo)resorcinol By Flow Injection Analysis"
Anal. Chim. Acta 1995 Volume 314, Issue 1-2 Pages 51-55
Kate Grudpan, Ponlayuth Sooksamiti and Saisunee Laiwraungrath*

Abstract: The determination of uranium in tin tailings by FIA was based on the formation of the colored complex between U(VI) and 4-(2-pyridylazo)resorcinol (PAR). Tin tailings (0.5-1 g) were digested with 10 mL HF and 10 mL HNO3 for 1 h on a steam bath and the digest was evaporated to dryness. After cooling, 5 mL HNO3 was added and the solution was evaporated to dryness. The residue was dissolved in 20 mL 4 M HNO3, the resulting mixture was filtered and the filtrate was diluted to 200 mL with water. Portions (250 µL) of the solution were injected into a mixed stream of triethanolamine buffer of pH 8 (74.6 mg/ml; 4 ml/min) and reagent (4 ml/min). The reagent stream contained 2 g/l PAR, 5 g/l trans-1,2-diaminocyclohexane-NNN'N'-tetraacetic acid monohydrate and 15 g/l sulfosalicylic acid at pH 7-8. The flow was carried to a reaction column (8 cm x 3.2 mm i.d.) to the detection cell where the absorbance at 530 nm was monitored. The calibration graph was linear up to 16 mg/l U(VI) and the detection limit was 0.28 mg/l. The RSD (n = 12) was 3.5% for 5 mg/l U(VI). The sample throughput was 60 samples/h.
Uranium Tin tailings Spectrophotometry

"Flame Atomic Absorption Spectrometric Determination Of Cobalt In Biological Materials Using A Flow Injection System With Online Preconcentration By Ion-pair Adsorption"
Anal. Chim. Acta 1995 Volume 316, Issue 3 Pages 329-335
Xuezhu Liu and Zhaolun Fang*

Abstract: Traces of cobalt in biological materials were determined by flow injection flame atomic absorption spectrometry. The analyte was pre-concentrated and separated from the bulk of the matrix by online ion-pair adsorption of the cobalt-nitroso-R salt complex in the presence of tetrabutylammonium bromide as a counter-ion reagent in a flow injection system. The ion-pair was collected on an online C-18 micro-column and eluted by ethanol directly into the nebulizer-burner system of an atomic absorption spectrometer. The interference from iron was masked by merging a sodium citrate solution to the sample flow. An enhancement factor of 40 and a sampling frequency of 45 h-1 were obtained for a collecting time of 60 s. The detection limit (3s) in the sample digest was 3 µg L-1. The relative standard deviation at the 50 µg L-1 cobalt level was 2.4%. The analytical results obtained for standard reference biological material were in good agreement with the certified or reference values.
Cobalt Biological Spectrophotometry Sample preparation

"Indirect Bioluminescent Determination Of Europium(III) Using Flow Injection Analysis And Online Reduction"
Anal. Chim. Acta 1997 Volume 339, Issue 3 Pages 225-229
St&eacute;phane D. Clerc, Roger A. Jewsbury*, Michael G. Mortimer and Jiang Zeng

Abstract: A stream of 10 mM HCl containing Eu(III) passed through a Zn amalgam reductor column (4 cm x 6 mm i.d.; preparation described), the eluate merged with a carrier stream of 0.1 M phosphate buffer of pH 6 containing 20 µM-flavin mononucleotide and 120 µM-decanal and the combined streams passed through a 15 cm coiled tube adjacent to a photomultiplier tube (detector). The total flow rate was 7.5 ml/min. Portions (85 µL) of ~0.05 µM-luciferase in 0.1 M phosphate buffer of pH 7 containing 149 µM-BSA and 6.5 mM DTT were injected into the carrier stream to facilitate luminescence determination of Eu(III). A calibration graph was established from 0.5 (detection limit) to 100 µM-Eu(III). RSD and recoveries are not stated. Up to 1 mM levels of Sm(III) Yb(III), Nd(III), Y(III), Fe(II), Ca(II) and Mg(II) did not interfere. However, Ti(IV) is detected by the system described above and hence would interfere in Eu(III) determinations (cf. Jewsbury and Zeng, J. Chem. Soc. Chem. Commun., 1993, 1677). The analysis rate was 60/h. Europium(III) is determined in a flow system based on the reduction of flavin mononucleotide, FMN, by Eu(II) followed by bacterial bioluminescence. Using flow injection analysis, Eu(III) is first reduced to Eu(II) in a zinc amalgam mini-column. The Eu(II) then reduces FMN to FMNH(2) and the bioluminescence produced on aerial oxidation of FMNH(2) in the presence of alkanal mono-oxygenase (FMN linked), EC 1.14.14.3, and n-decanal is used to determine the Eu(II). Calibration is achieved for 5 x 10^-7 to 1 x 10^-4 M Eu(III) with a limit of detection (3 s.d.) of 5 x 10^-7 M and an analysis rate of 60 h-1. The effects of possible interferences are reported.
Europium(3+) Bioluminescence

"Flow Injection Determination Of Aluminum(III) Ions And Al13O4(OH)24 (H2O)127+ Species Using A 1.3 S Reaction With 8-quinolinol-derivatized Fractogel"
Anal. Chim. Acta 1997 Volume 343, Issue 1-2 Pages 19-32
Stuart L. Simpson, Kipton J. Powell*, and Nils H. S. Nilsson

Abstract: A flow injection spectrophotometric method is described to determine (i) 'free Al', viz. Al3+ plus Al(OH)2+ and very labile Al complexes, (ii) Al in moderate labile complexes and (iii) Al-hydroxo polymers, viz. Al13(OH)327+. A sample volume of 650 µL was inserted into a carrier stream (1 ml/min) of 0.05 M sodium acetate/0.05 M NaCl of pH 5 and propelled through a column reactor (22 µL) containing 8-quinolinol immobilized onto Fractogel. Free Al and Al-hydroxo polymers were retained by the column while moderate labile Al complexes passed through. The column effluent was merged with a reagent stream formed online by merging 2 M acetate buffer of pH 5.3 (0.21 ml/min) and 2 mM chrome azurol S (0.04 ml/min). The flow then passed through a reactor coil (300 cm x 0.5 mm i.d.) to the detection cell (70 µL) where the absorbance was measured at 545 nm. Free Al was eluted from the column reactor with 250 µL 0.02 M NaOH and the Al-hydroxo polymers were eluted with 60 µL 0.2 M NaOH using a 2 min stopped-flow procedure. The linear range of the method was 0.3-16 µM-Al3+, the detection limit was 70 nM and the RSD for 0.5 µM was 7%. The method was applied to aqueous soil extracts and humic waters and the results for free Al were compared to those obtained by the 7 s chrome azurol S method.
Aluminum(III) Aluminum, free Environmental Environmental Spectrophotometry Sample preparation

"The Aluminum(III)-4-nitrocatechol System: Potentiometry, Voltammetry And Application To The Determination Of Reactive Al(III)"
Anal. Chim. Acta 1997 Volume 345, Issue 1-3 Pages 5-15
A. J. Downard, R. J. Lenihan, S. L. Simpson, B. O'Sullivan and K. J. Powell

Abstract: Four Al(III)-4-nitrocatechol (4ncat) complexes were studied by potentiometry and voltammetry from pH 3-11 and with 4ncat:Al(III) ratios of 1-4. A technique involving amperometric detection was described for determining Al(III) in environmental materials. The method was based on the quantitative formation of [Al(4ncat)3]3- at pH 9. The method was applied to aqueous extracts from soils. An extract (700 µL) was inserted into a carrier stream of acetate buffer of pH 5 at a flow rate of 0.98 ml/min then propelled through an oxine microcolumn (22 µl). The retained Al3+, Al(OH)2+, Al(OH)2+ and labile Al complexes (e.g. AlF2+, AlF2+) were subsequently eluted with 200 µL 0.02 M KOH to form an analyte plug of [Al(OH)4]-. The analyte plug was merged with a reagent stream prepared online from ammonium buffer of pH 9 at a flow rate of 0.36 ml/min and 1.6 mM 4ncat at a flow rate of 0.03 ml/min. Detection was carried out at a glassy carbon electrode at 0.3 V vs. SCE (Pt auxiliary electrode). Calibration graphs were linear from 0.4-8 µM-Al(III); the detection limit was 0.08 µM. RSD were 3.5% and 0.3% for 1 and 10 µM-Al(III), respectively.
Aluminum(III) Environmental Amperometry Electrode Voltammetry Potentiometry Sample preparation

"Prototype Of A Newly Developed Immunochemical Detection System For The Determination Of Pesticide Residues In Water"
Anal. Chim. Acta 1997 Volume 347, Issue 1-2 Pages 187-198
Petra M. Kr&auml;mer*, Bert A. Baumann and Peter G. Stoks

Abstract: Methods based on flow injection immunoaffinity analysis (FIIAA) are described for determining atrazine and diuron in water. The analyzes were performed on a prototype instrument consisting of an affinity column packed with protein A immobilized on polymethacrylate and a flow-through fluorimeter. The sequential experimental procedure was carried out by subjecting the affinity column to the following treatments; (i) incubating with anti-pesticide antibodies, (ii) rinsing, (iii) incubating with pesticide solution, (iv) rinsing, (v) incubating with peroxidase tracer for 3 min, (vi) rinsing and (vii) incubating with 3-hydroxyphenyl propionic acid/H2O2 substrate solution. The product of the enzyme reaction was detected at 415 nm (excitation at 320 nm). Between each determination the protein A affinity column was regenerated with 100 mM sodium citrate buffer. The linear range of the assays was 0.02-0.5 µg/l for both atrazine and diuron and the concentration producing 50% inhibition of the maximum response for atrazine was 0.1 µg/l. Diuron and isoproturon had no effect on the atrazine determination but simazine caused a decline in the atrazine signal. Recoveries for 0.02-0.5 µg/l atrazine were satisfactory.
Atrazine Diuron Environmental LC Immunoassay Fluorescence

"Flow Injection Enzyme Immunoassay Of Atrazine Herbicide In Water"
Anal. Chim. Acta 1997 Volume 347, Issue 1-2 Pages 111-120
Bjarni Bjarnason, Nikolas Bousios, Sergei Eremin and Gillis Johansson*

Abstract: The FIA manifold was equipped with an immunocolumn (13 x 1 mm i.d.) packed with an anti-atrazine antibody immobilized onto an epoxy activated Poros support (20 µm particle diameter) and a spectrophotometric detector. The antibody was raised in rabbits using an atrazine derivative conjugated to keyhole limpet haemocyanin (KLH). The enzyme tracer was prepared by coupling horseradish peroxidase with an atrazine derivative. The assays were performed by injecting 100 µL of an analyte/enzyme tracer mixture into the eluting buffer stream (50 µl/min) of 100 mM acetate buffer at pH 5 containing 0.5% Tween-20, 0.05% Kathon CG and 0.5 mM EDTA. After 5 min, 200 µL of the substrate solution was injected and the absorbance at 405 nm was monitored. The substrate solution contained 0.36 mM 2,2'-azino-di-(3-ethylbenzthiazoline-6-sulfonic acid) and 5 mM H2O2 in the eluting buffer. The column was regenerated between each measurement by injecting 200 µL 100 mM phosphoric acid/methanol (1:1). The detection limit for atrazine was 0.5 ng/ml. The antibody exhibited some cross-reactivity with other triazines with similar structures (e.g., simazine, propazine and terbutylazine) but low cross-reactivity towards 2,4-D.
Atrazine Environmental Immunoassay Spectrophotometry

"Development Of A Highly Sensitive Enzyme-linked Immunosorbent Assay For Atrazine. Performance Evaluation By Flow Injection Immunoassay"
Anal. Chim. Acta 1997 Volume 347, Issue 1-2 Pages 149-162
Jordi Gasc&oacute;n, Anna Oubi&ntilde;a, Berta Ballesteros, Dami&agrave; Barcel&oacute;, Francisco Camps, Mar&iacute;a-Pilar Marco*, Miguel Angel Gonz&aacute;lez-Mart&iacute;nez, Sergi Morais, Rosa Puchades and Angel Maquieira

Abstract: Three polyclonal antisera obtained from immunized rabbits and nine hapten-horseradish peroxidase enzyme tracers were screened to develop a ELISA for atrazine in water. The optimized competitive ELISA was carried out on a antisera-coated microtitre plate by incubating the atrazine sample for 30 min, then adding the enzyme tracer and incubating for a further 6 min. After washing, the tetramethylbenzidine/H2O2 substrate solution was added. The reaction was stopped after 30 min with H2SO4 and the absorbance was measured at 450 nm. The detection limit for atrazine was 0.043 nM. Cross-reactivity studies showed that the assay was specific and that other triazines were only detected to a minor extent. A flow injection immunoanalysis (FIIA) method for atrazine was performed by passing a atrazine sample/enzyme tracer mixture through an immunoreactor containing immobilized antibodies. The 3-(p-hydroxyphenyl)-propanoic acid/H2O2 substrate solution was then injected onto the column and incubated for 60-240 s. The product of the enzyme reaction was detected by fluorimetry at 405 nm (excitation at 320 nm). The working range of the FIIA method was 0.075-2.5 µg/l and the detection limit was 75 ng/l (0.35 nM). The ELISA and FIIA methods were evaluated by analyzing water samples containing mixtures of atrazine and other pesticides at the ppb level.
Atrazine Water Immunoassay Fluorescence

"A New Evaluation Technique For FIA Measurements Projective Reference Evaluation"
Anal. Chim. Acta 1997 Volume 348, Issue 1-3 Pages 161-166
B. Hitzmann*, A. L&ouml;hn, M. Arndt, R. Ulber and C. M&uuml;ller

Abstract: In this contribution we present a new evaluation technique used for flow injection analysis (FIA) measurements called projective reference evaluation. Using different FIA systems employing an enzyme cartridge in combination with an oxygen electrode for glucose measurement, an enzyme field effect transistor for urea measurement as well as an enzyme optode for penicillin measurement it will be demonstrated, that the new evaluation technique is able to calculate reliable analyte concentrations even from heavily faulty signals. The occurrence of a fault can be detected very easily, using the new technique. Furthermore, it will be shown, that the linear measurement range of a FIA system can be extended significantly. Applying this evaluation technique the whole information of the analysis system inherently hidden in the measurement signal is exploited. The simplicity of the procedure implied its use for online application in a process FIA where a reliable evaluation as well as a fast fault detection is imperative. 19 References
Penicillin Urea Glucose Electrode Field effect transistor

"Coupling Of Membrane-immobilized Enzyme Reaction And Heteropoly Acid Luminol Chemiluminescence Reaction For The Determination Of Adenosine-5'-triphosphate"
Anal. Chim. Acta 1997 Volume 349, Issue 1-3 Pages 159-164
Terufumi Fujiwara, Kiyomi Kurahashi and Takahiro Kumamaru*

Abstract: A method based on the combination of a membrane-immobilized enzyme reactor with a flow injection (FI) chemiluminescence (CL) detector was developed and applied to the determination of >10 nM adenosine-5'-triphosphate (ATP). Alkaline phosphatase from Escherichia coli was immobilized on a nitrocellulose membrane by adsorption. When a sample of ATP was circulated in this enzyme reactor, orthophosphate was produced from alkaline phosphatase-catalyzed hydrolysis of ATP. In the FI system, the enzymatically generated phosphate in the sample solution was led into the loop of an injection valve followed by its conversion into molybdovanadophosphoric acid by mixing with a reagent mixture containing ammonium molybdate, ammonium metavanadate and sulfuric acid. The heteropoly acid subsequently reacts with luminol in a basic medium to produce CL, proportional to ATP concentration. A detection limit (DL) of 10 nM and a dynamic range extending from the DL to 10 µM were obtained for ATP. The relative standard deviation for five replicate measurements of 1.0 µM ATP was 6.6%. 18 References
Chemiluminescence Sensor

"Application Of Factorial Design To Improve A FIA System For Penicillin Determination"
Anal. Chim. Acta 1997 Volume 350, Issue 3 Pages 353-357
Marta M. M. B. Duartea, Graciliano de O. Netob, Lauro T. Kubotab,*, Jos&eacute;L. L. Filhoc, Maria F. Pimenteld, Fernando Limaa and Valdinete Linsa

Abstract: A potentiometric FIA system for penicillin determination, employing penicillinase immobilized on silica gel, packed into a reactor, was improved by the use of statistically designed experiments. A two-level and three-factor factorial was used to find the best working conditions evaluating the influence of some parameters on the signal response of the system and the number of determinations per hour. These parameters were analyzed individually obtaining two level of the variables to be used in the factorial design: length of the reactor (1.5 and 2.0 cm), carrier flow rate (1.6 and 2.2 mi min-1) and sample volume (100 and 150 µL). The pure error on the measurements was estimated by authentic repetitions. The ideal working conditions taking into account a compromise between the best response signal and the number of determinations per hour (with the same importance) being chosen the level of factors: length of reactor 1.5 cm, carrier flow rate 2.2 mL min-1 and sample volume of 150 µL. Under these conditions the system allowed to analyze was about 45 samples per hour, during 73 days, with a standard deviation of 2.4% at concentration range between 10^-1 and 10^-3 mol L-1. 20 References
Penicillin Potentiometry

"Miniaturization A Well-defined Trend In Separation And Preconcentration Techniques"
Anal. Chim. Acta 1997 Volume 351, Issue 1-3 Pages 23-40
M. D. Luque de Castro*, and L. G&aacute;miz-Gracia

Abstract: An overview of the state-of-the-art on miniaturisation concerning the different types of separation techniques is presented. Four groups of these techniques can be distinguished. 105 References
GC Fluorescence Mass spectrometry Spectrophotometry Sample preparation

"Chemiluminescence Flow Sensor For The Determination Of Vitamin-b-12"
Anal. Chim. Acta 1997 Volume 357, Issue 1-2 Pages 127-132
Wei Qin, Zhujun Zhang* and Huajun Liu

Abstract: A novel chemiluminescence (CL) sensor for vitamin B-12 combined with flow injection analysis is presented in this paper. It is based on the catalytic effect of cobalt(II), liberated from vitamin B-12 by acidification, on the CL reaction between luminol, immobilized electrostatically on an anion-exchange column, and hydrogen peroxide electrochemically generated online via a negatively-biased electrode from dissolved oxygen in the flow cell. The sensor responds linearly to vitamin B-12 concentration in the 1.0 x 10^-3-10 mg L-1 range, and the detection limit is 3.5 x 10^-4 mg L-1 vitamin B-12. A complete analysis, including sampling and washing, could be performed in 1 min with a relative standard deviation of < 3.58. The system is stable for over 500 determinations and has been applied successfully to the determination of vitamin B-12 in pharmaceutical preparations. 27 References
Vitamin B12 Pharmaceutical Chemiluminescence Ion exchange Sensor

"Electrochemical Biosensors For Biogenic Amines: A Comparison Between Different Approaches"
Anal. Chim. Acta 1998 Volume 358, Issue 3 Pages 277-284
S. Tombelli and M. Mascini*

Abstract: Diaminase oxidase (DAO) has been examined in order to obtain a sensor for biogenic amines; the enzyme was immobilized directly on the surface of a platinum electrode, posed at +700 mV vs. Ag/AgCl, or immobilized on glass beads in a small reactor (diameter 2 mm, length 40 mm) and included in a flow injection analysis assembly. Moreover, it was coupled with horseradish peroxidase coimmobilized and coupled with a glassy carbon electrode using ferrocene monocarboxylic acid as mediator dissolved in the carrier stream. Low detection limits were obtained in all cases with some differences; the selectivity was quite similar in the different assemblies. Moreover, we showed that selectivity can be changed using DAO, obtained from different starting materials not commercial available such as pea (Cicer arietinum).
Amines, biogenic Sensor Electrode Electrode Electrode

"Preconcentration And Separation Of Inorganic Selenium Species On Activated Alumina"
Anal. Chim. Acta 1998 Volume 363, Issue 2-3 Pages 141-146
Krystyna Pyrzy&#324;ska, Przemys&#322;aw Drzewicz and Marek Trojanowicz

Abstract: A simple and convenient method has been developed for the speciation of inorganic selenium in aqueous solutions using alumina microcolumn. Both Se(IV) and Se(VI) are retained on the microcolumn in a widely pH range of solution. The successive gradient elution of pre-concentrated species with ammonia solution allows to differentiate between them. Se(VI) and Se(IV) were eluted with 1 mL of 1 mol L-1 NH3 and 6 mL of 4 mol L-1 NH3, respectively, and determined by graphite furnace atomic absorption spectrometry. The detection limit for Se(VI) is 0.80 µg mL-1 and for Se(TV) 49 ng L-1. The method has been applied to the speciation of inorganic selenium in natural water samples.
Selenium(IV) Selenium(VI) Environmental Spectrophotometry

"Use Of Column With Modified Silica For Interfering Retention In A FIA Spectrophotometric Method For Direct Determination Of Vitamin C In Medicine"
Anal. Chim. Acta 1998 Volume 366, Issue 1-3 Pages 11-22
Julio Cesar B. Fernandes, Graciliano de Oliveira Neto and Lauro T. Kubota*

Abstract: A flow injection analysis (FIA) system with a column packed with silica modified with aminopropyl groups was used as a reactor in the spectrophotometric determination of L-ascorbic acid at 265 nm. The column (2.79 mm ID, 50 mm length) packed with modified silica (200 mg silica treated with 3-aminopropyltriethoxysilane) was used to eliminate interfering compounds by ion pair formation with amino groups. The interfering compounds studied included tartaric, citric, oxalic, and maleic acids, glucose, fructose, EDTA, Na benzoate, and Na salicylate. A processing rate of 30 samples/h, detection limit of 2.0 x 10^-6 M, and linearity range between 10^-5 and 10^-4 M were achieved in optimized conditions. The relative standard deviation was 1.5% (n=20) for a 5.0 x 10^-5 M ascorbic acid solution The method was applied to drug samples to determine ascorbic acid; the results were in agreement of the nominal values.
Ascorbic acid Pharmaceutical Spectrophotometry

"Development Of A Potentiometric Procedure For Determination Of Glycerol And 2,3-butanediol In Wine By Sequential Injection Analysis"
Anal. Chim. Acta 1998 Volume 366, Issue 1-3 Pages 193-199
Gilmara C. Lucaa, Boaventura F. Reisb,*, Elias A. G. Zagattob, Maria Concei&ccedil;&atilde;o B. S. M. Montenegroc, Alberto N. Ara&uacute;joc and Jos&eacute; Luis F. C. Limac

Abstract: A flow sequential injection procedure with potentiometric detection for determination of glycerol and 2,3-butanediol in wine is described. The method was based on reaction of IO-4 ions with glycerol and 2,3-butanediol with the reagent consumption afterwards being continuously monitored by means of a PVC periodate ion selective electrode constructed with tubular configuration and without inner reference solution. The electrode membrane was based on bis(triphenylphosphoranylidene) ammonium periodate dissolved in 2-nitrophenyloctyl ether and immobilized in PVC. In the developed set-up, a 2.0 x 10^-2 mol L-1 sodium periodate solution was used as carrier. To minimize interferences caused by other reducing components in the samples, a mini column packed with the anionic Amberlite IRA 400 (20-50 mesh, OH- form) resin was coupled to a lateral port of the valve. The feasibility of the anal. proposal was ascertained by determining polyols as glycerol in a set of red and white wine. The accuracy of the proposed method was assessed by standard addition samples with glycerol. Recoveries within the 96.0-106.9% range were calculated A sample throughput of 33 per h, a reagent consumption of 9.4 mg of sodium periodate per determination and a relative standard deviation of results lower than 1% were obtained.
Glycerol 2,3-Butanediol Wine Red Wine White Potentiometry Electrode Electrode Electrode

"Online Preconcentration System For Lanthanum Determination In Urine Using FI-ICP-AES"
Anal. Chim. Acta 1998 Volume 366, Issue 1-3 Pages 201-207
O. Vicente, A. Masi, L. Martinez*, R. Olsina and E. Marchevsky

Abstract: An online lanthanum pre-concentration and determination system implemented with inductively coupled plasma-at. emission spectrometry (ICP-AES) associated to flow injection (FI) method was studied. For the retention of lanthanum, quinolin-8-ol and Amberlite XAD-7 were used at pH 9.5. The lanthanum complex was removed from the micro-column with nitric acid. The value of detection limit for the pre-concentration of 100 mL of aqueous solution was 0.09 ng mL-1 with a relative standard deviation (RSD) of 1.5%, calculated with the peak heights obtained. The calibration graph using the pre-concentration system for lanthanum was linear with a correlation coefficient of 0.9993 at levels near the detection limits up to at least 100 ng mL-1. The method was successfully applied to the determination of lanthanum in urine samples.
Lanthanum Urine Spectrophotometry

"Determination Of Ammonia In Wastewaters Containing High Concentrations Of Surfactants By Flow Injection Potentiometry With Online Sample Clean-up"
Anal. Chim. Acta 1998 Volume 367, Issue 1-3 Pages 193-199
Hongda Shen, Terence J. Cardwell* and Robert W. Cattrall

Abstract: It was demonstrated that surfactants lead to problems in the anal. of NH3 in gas-diffusion flow injection by wetting the membrane to allow transport of potentially interfering species to the detector. An online clean-up procedure, using an activated C cartridge to remove ionic and non-ionic surfactants (≤1000 mg/L) and other organic compounds from aqueous samples, is described. Ammoniacal nitrogen was determined in synthetic samples by gas-diffusion flow injection with a nonactin-based potentiometric sensor used as an NH4+ ion detector. Analyses were performed at a sampling rate of ~25/h; the cartridge was effective for at least 1000 injections of 50 µL samples at 1-180 mg/L concentrations The procedure was used to analyze wastewater; it was efficient in removing ionic and non-ionic surfactants from acidified (pH 1) samples.
Ammonia Waste Potentiometry Electrode

"Online Separation And Preconcentration Of Cadmium, Lead And Nickel In A Fullerene (C60) Minicolumn Coupled To Flow Injection Tungsten Coil Atomic Absorption Spectrometry"
Anal. Chim. Acta 1998 Volume 368, Issue 3 Pages 255-263
Marcia M. Silvaa, Marco A. Z. Arrudab, Francisco J. Kruga,*, Pedro V. Oliveirac, Zilvanir F. Queiroza, Mercedes Gallegod and Miguel Valc&aacute;rceld

Abstract: A flow system was coupled to a W coil electrothermal atomizer (150 W) for online separation and pre-concentration of Cd, lead and Ni based on the formation of DDC complexes and sorption into a minicolumn packed with fullerene C60. Three way solenoid valves used for sample and reagents management as well as the W coil power supply were controlled by a computer running a program written in Visual Basic, which was employed in synchronism with the original software of the atomic absorption spectrometer. The fullerene column (5 mm length, 2 mm internal diameter) was inserted into the tip of the autosampler arm, and elution was performed by sampling 35 µL of MeOH from the autosampler cup. With 3.0 mL of sample (loading time of 60 s) enrichment factors ranging from 100 to 150 were achieved. The detection limits for Cd, lead and Ni were 2.2, 23 and 75 ng L-1, respectively. No interference effects were observed on Cd, lead and Ni pre-concentration in the presence of up to 106 fold concentrations of Na, K, Ca or Mg. Application of t-test to the results obtained by the proposed method and the certified values of Cd, lead and Ni in five water reference materials did not reveal significant differences at the 5% probability level.
Cadmium Lead Nickel Environmental Blood Spectrophotometry

"Comparison Of Flow Injection Analytical Biosystems Based On Open-tube And Packed-bed Enzyme Reactors"
Anal. Chim. Acta 1998 Volume 370, Issue 1 Pages 47-58
M. Jurkiewicz, S. Alegret and E. F&agrave;bregas*

Abstract: A comparison between the most widely used enzyme reactors in flow injection analysis (FIA) systems was realized. These reactors were the open-tube reactors and the packed-bed reactors. The comparison was realized with three different enzymes (urease, creatinine, iminohydrolase and creatine amidinohydrolase). The enzymes were covalently immobilized on controlled-pore glass beads (CPG). These beads were used as the filling for the packed-bed reactors. The enzymes were also immobilized covalently on the inner wall of nylon tube reactors. All three enzymes were used in clinysis analysis and they have clearly distinguished activities. All of them produced ammonium ions as a consequence of their interaction with their respectively. substrates. The single channel FIA system used for the evaluation and the comparison of the reactors worked automatically and included a flow bioreactor and an ammonium-ion sensor. The FIA systems used with the different bioreactors were optimized to obtain the largest signal in the shortest time. Once optimized, the performance of the reactors were evaluated and compared while working with each enzyme. The parameters to evaluate were: calibration parameters (y-ordinate, slope and linear), reproducibility, conversion ratio (yield) of the enzyme reaction in the reactor, dynamic parameters (response time and anal. time) and lifetime. The comparison of the bioreactors working under optimal conditions showed that the packed reactors had a higher conversion ratio, a higher sensitivity (slope of the calibration curve), a smaller lower detection limit and shorter response times. Open-tube reactors showed a higher reproducibility, a higher upper detection limit and a diminished amt. of reagent at the optimal flow rate. Anal. time was lower in open-tube reactors since the packed-bed reactors are difficult to wash after sample injection and the signal took longer to return to the baseline after an FIA peak. In some cases, the baseline value was not fully reached again.
Uric acid Creatine Creatinine Electrode Potentiometry

"Rapid Determination Of Manganese In Seawater By Flow Injection Analysis With Chemiluminescence Detection"
Anal. Chim. Acta 1991 Volume 249, Issue 2 Pages 469-478
Thomas P. Chapin, Kenneth S. Johnson and Kenneth H. Coale

Abstract: The manganese was concentrated on a column of 8-hydroxyquinoline immobilized on Fractogel and was eluted with 0.0025 M HCl. The eluate at 2.7 mL min-1 was mixed with a reagent containing 0.25 mM 7,7,8,8-tetracyanoquinodimethane (I), 0.30 mM 2',4',5,7'-tetrabromofluorescein and 4 mM didodecylmethylammonium bromide and with 0.01 M NaOH, both at 1.3 mL min-1. The luminescence caused by the oxidation of I and catalyzed by Mn(II) was measured by a photomultiplier. The calibration graph was rectilinear from 1 to 100 mM, with a detection limit of 0.1 nM. In the analysis of standard sea-waters the results agreed closely with certified values and gave standard deviations (n = 3 and 4) of 2.8 and 0.07 for ~43 and 0.48 nM, respectively.
Manganese Sea Chemiluminescence

"Alternative Use Of Flow Injection Analysis And The Combination Of Liquid Chromatography And Flow Injection Analysis For The Determination Of Total And Individual Bile Acid Concentrations In Serum"
Anal. Chim. Acta 1991 Volume 249, Issue 2 Pages 461-467
A. Membiela, F. L&aacute;zaro, M. D. Luque de Castro and M. Valc&aacute;rcel

Abstract: The sample was passed through a Sep-Pak C18 cartridge and the bile acids were eluted with methanol. The total acid content was determined by flow injection analysis and was based on the oxidation of the acids, catalyzed by 3-α-hydroxysteroid dehydrogenase and NAD+, the reduced forms of which being monitored fluorimetrically. Samples with abnormal acid concentration. were analyzed for individual analytes on a column (20 cm x 4 mm) of Nucleosil C18 (10 µm) with methanol - 20 mM KH2PO4 (9:1) as mobile phase, pH 4.5, with detection at 460 nm (excitation at 340 nm). Recoveries by both methods were between 87.3 and 115.7%. The calibration graphs were rectilinear from 1 to 10 µg mL-1, and the coefficient of variation (n = 11) were between 2.7 and 3.0% for 4 µg mL-1 of each acid.
Bile acid Blood Serum LC Fluorescence

"Determination Of Ortho- And Pyrophosphates In Waters By Extraction Chromatography And Flow Injection Analysis"
Talanta 1990 Volume 37, Issue 10 Pages 889-894
B. Ya. Spivakov, T. A. Maryutina, L. K. Shpigun, V. M. Shkinev and Yu. A. Zolotov, E. Ruseva and I. Havezov

Abstract: A flow injection manifold is described which includes an extraction mini-column and a post-column spectrophotometric detector. The sum of ortho- and pyro-phosphate was determined in an aqueous sample by hydrolysis of the pyrophosphate at 50°C using inorganic pyrophosphatase, then the solution was mixed with a stream of 1 M HNO3 before passage through a column of Chromaton N-AW-HMDS modified with dioctyltin dichloride. The column was washed with water and Tris - HCl buffer for 1 min, and total orthophosphate was eluted with 0.5 M HCl. The orthophosphate was determined by mixing the solution with 1 M HNO3, pumping the stream through the column and elution with HCl as before, followed by monitoring the absorbance at 660 nm of the molybdenum blue produced in a reaction coil. For a sample volume of 6 ml, the calibration graph was rectilinear from 5 to 100 ng mL-1 of P, and the detection limit was 0.3 ng mL-1. The recovery of the ions was >96%. The method was used for the analysis of river water.
Phosphate Pyrophosphate River Spectrophotometry Sample preparation

"Determination Of Chloramphenicol By Coupling A Continuous Reduction System To An Atomic Absorption Spectrometer"
Talanta 1990 Volume 37, Issue 12 Pages 1129-1132
R. Montero, M. Gallego and M. Valcarcel

Abstract: Sample solution (90 µL) at pH 3.7 to 4.2 was injected into the water carrier stream and passed through the Cd or Zn reductor column where the nitro-group was reduced. The released Cd or Zn cations were then determined by AAS; peak height was proportional to the concentration. of drug injected. Chloramphenicol could be determined in the range 2 to 30 µg mL-1 and the sampling frequency was 150 h-1. The detection limits were 0.7 and 1.3 µg mL-1 for the Zn and Cd columns, respectively; the corresponding recoveries and coefficient of variation (n = 7) were 99.5 and 1.1 and 99.8 and 2.1%. The method was applied to pure powders, capsules, tablets, oral suspensions and eye ointments. Advantages over the previously reported batch method included low sample and reagent consumption, lower cost and higher sensitivity and precision.
Chloramphenicol Spectrophotometry

"Optimization Of Flow Injection Systems For Determination Of Substrates By Means Of Enzyme Amplification Reactions And Chemiluminescence Detection"
Talanta 1991 Volume 38, Issue 3 Pages 275-282
Elo H. Hansen, Lars N&oslash;rgaard and Mikael Pedersen,

Abstract: A flow injection system is described which incorporates a small column reactor containing two co-immobilized, synergically operating enzymes, allowing determination of trace amounts of substrates by enzyme amplification and subsequent chemiluminescence determination of H2O2 generated in repeated redox cycling. Optimization of the enzymatic degradation and detection steps and use of lactate oxidase and lactate dehydrogenase, produces an amplification factor of >140 for lactate and pyruvate; the detection limits were 48 and 103 nM, respectively. Calibration graphs were rectilinear for up to 6 µM. The sampling rate was 50 to 60 h-1. For glucose oxidase and glucose dehydrogenase, the amplification factor was only 3 to 4. The reasons for the large discrepancy between the enzyme systems were discussed.
Chemiluminescence

"Determination Of Cadmium, Lead And Copper In Water Samples By Flame Atomic Absorption Spectrometry With Preconcentration By Flow Injection Online Sorbent Extraction"
Talanta 1991 Volume 38, Issue 6 Pages 613-619
Zhaolun Fang, Tiezheng Guo and Bernard Welz*,

Abstract: Sample was mixed with aqueous 0.05% diethylammonium diethyldithiocarbamate and the heavy metal complexes formed were concentrated on a 5-mm micro-column of Bakerbond C18 bonded silica (40 to 63 µm). The complexes were eluted with ethanol or methanol (2.5 mL min-1) and determined by flame AAS at 283.3, 228.8 and 324.7 nm, for Pb, Cd and Cu, respectively. The flow injection system is described in detail (diagrams given). The operating conditions were optimized and the methods was applied in the analysis of seawater, drinking water and a reference material. Results for the latter agreed with certified values. Recoveries of Cd and Pb from seawater and potable water were 94 to 102%. Detection limits were 0.3, 3 and 0.2 µg L-1 of Cd, Pb and Cu, respectively; coefficient of variation (n = 11) were 1.5%. Sampling rate was 120 h-1.
Cadmium Copper Lead Sea Water Spectrophotometry Sample preparation

"Determination Of Copper At Ng-levels By Inline Preconcentration And Flow Injection Analysis Coupled With Flame Atomic Absorption Spectrometry"
Talanta 1991 Volume 38, Issue 7 Pages 753-759
Rajesh Purohit and Surekha Devi*

Abstract: The synthesis and characterization of oxine (I) - formaldehyde (II) - resorcinol and I - II - hydroquinone chelating resins are described. Conditions were optimized for the pre-concentration. of Cu from binary and ternary mixtures also containing Co, Pb and/or Ni by batch extraction and by column chromatography, alone or in a flow injection system, with use of the resins. For batch pre-concentration, a pH of ~2.5 to 3 was optimal whereas in the flow injection method a broader pH range (~2 to 3.5) could be used. Separations of binary mixtures of Cu(II) with Ni(II) or Pb(II) at the µg mL-1 level did not show any cross contamination. A flow injection analytical procedure is described in which Cu was pre-concentrated by passage of the sample solution through a microcolumn (2 cm x 2 mm) containing the oxine resin. The carrier (2 mL min-1) was 0.2 M acetate or -phosphate buffer (pH 2 or 3, adjusted with HCl). The column was washed with buffer, and the chelated Cu was eluted by the injection of 50 µL of 0.5 M HCl, and was determined by flame AAS. The detection limit was 5 ng mL-1 with pre-concentration. from a 15 mL solution
Copper Chromatography Spectrophotometry Sample preparation

"Determination Of Trace Amounts Of A Proteolytic Enzyme By FIA With A Stopped-flow And An Online Preconcentration Technique"
Talanta 1991 Volume 38, Issue 8 Pages 851-856
Thomas G&uuml;beli, Jaromir Rika* and Gary D. Christian,

Abstract: In the cited technique (diagram and details given) 5 mM N-succinyl-L-Ala-L-Ala-L-Pro-(4'-nitrophenylalaninamide) substrate was injected into a stream of-Tris-HCl buffer (pH 8.3) and this stream was merged with the enzyme sample solution The mixture was incubated at 40°C for 5 to 30 min during the stopped-flow period and the hydrolysis product, p-nitroaniline was concentrated on a column of 10 mg of C18 (40 µm), eluted with methanol, in counter-current mode, and detected at 400 nm. The limit of detection was 0.1 µU mL-1 of protease with a reaction time of 30 min and the coefficient of variation (n = 2 or 3) were from 2.8 to 17%.
Enzymes, proteolytic Spectrophotometry

"Post-column Formation Of Fluorophores From Nitrogenous Pesticides By UV Photolysis"
Talanta 1991 Volume 38, Issue 8 Pages 913-922
Bragwandas M. Patel and H. Anson Moye*, Robert Weinberger

Abstract: Nitrogenous pesticides were analyzed with use of a system (diagram given) described previously (J. Agric. Food Chem., 1990, 38, 126) with C18 analytical columns and linear gradient elution (1 mL min-1) with acetonitrile - methanol - water. Acetone, acetophenone, Triton X-100 and the photocatalyst TiO2 were assessed as photosensitizers to enhance the UV photolysis and fluorescence response. The solvent system giving the highest fluorescence response varied with the pesticide analyzed (results tabulated). The method was applied in the determination of nitrogenous pesticides in ground water with recoveries from 95 to 115%. Calibration graphs were rectilinear and limits of detection were 5 to 50 µg Kg-1. The photo-induced fluorescence detection system may be used in LC and flow injection analysis systems.
Pesticides, nitrogenous Ground LC Fluorescence

"Flow Analysis Of Silicate Rocks For Zirconium"
Talanta 1991 Volume 38, Issue 10 Pages 1119-1123
R. Kuroda, K. Oguma, K. Kitada and S. Kozuka

Abstract: A flow analysis system involving online configuration of an anion-exchange column has been examined to enrich and determine trace concentration of Zr of several ppm to hundred ppm levels in silicate rocks and minerals. About 100 mg of sample was decomposed by fusion with boric acid - Li2CO3 and taken up with 1 M HCl to 100 mL. A 1- or 4 mL portion of sample was introduced into an aqueous carrier stream, merged with H2SO4 and passed through a Bio-Rad AG1-X8 (100 to 200 mesh; Cl- form) column, eluted with HCl, color-developed with Arsenazo III and detected spectrophotometrically at 665 nm. Effects of foreign ions are tabulated.
Zirconium Silicate Silicate Spectrophotometry Sample preparation

"Online Alumininium Preconcentration On Chelating Resin And Its Flow Injection Analysis - Spectrofluorimetric Determination In Foods And Dialysis Concentrates"
Talanta 1991 Volume 38, Issue 12 Pages 1387-1392
P. Fern&aacute;ndez, C. P&eacute;rez Conde, A. Guti&eacute;rrez and C. C&aacute;mara*,

Abstract: A selective and sensitive technique whereby Al is complexed with 5,7-dibromoquinolin-8-ol and extracted into ethyl ether before separation from interferants in a chelating micro-column and spectrofluorimetric determination at 525 nm (excitation at 400 nm). Other complexes and solvent systems are considered but are found to be inferior. Batch- and flow injection methods are studied and the latter is found to be the most selective. Optimum conditions are 0.05 M acetic acid buffer of pH 5.5 with complex concentration. in ethyl ether of 0.05%, aqueous and organic flow rates of 0.36 and 0.62 mL min-1, respectively, for a 185 µL sample injection volume. The calibration graph is rectilinear from 1 to 50 ng mL-1 of Al; detection limit is 0.3 ppb Al with coefficient of variation at 4 ppb of 3%. The method is applied in dialysis fluids, foods and tap water.
Aluminum Food Water Dialysis Fluid Fluorescence

"Rapid Sequential Determination Of Inorganic Mercury And Methylmercury In Natural Waters By Flow Injection - Cold Vapor-atomic-fluorescence Spectrometry"
Talanta 1992 Volume 39, Issue 11 Pages 1537-1542
Wei Jian and C. W. McLeod*,

Abstract: In the cited technique, measurement is based on time-resolved detection of inorganic and methylmercury species following separation and enrichment on a PTFE micro-column (6 cm x 1.5 mm) of sulfydryl cotton fiber (~0.015 g). The column forms an integral part of the flow injection system (described). The carrier (10 mM HCl), oxidant (Br- - BrO3-) and reductant (SnCl2) were continuously pumped at flow rates of 1.5 mL min-1 each. After injection of the sample into the carrier stream, inorganic Hg passed through the column to undergo reduction - phase separation followed by AFS detection. Hydrochloric acid (3M) was injected to eluted methylmercury from the column which was oxidized and reduced as before thus allowing a rapid sequential monitoring of both species. Optimization of the operating conditions is discussed. The calibration graph was rectilinear from 50 ng L-1 to 10 µg L-1 of methylmercury; the limit of detection was 6 ng l-1. There was no interference from co-existing metal ions. Application to river water samples is demonstrated.
Mercury Methylmercury ion River Fluorescence

"Flow Injection System With Ion-exchange For Spectrophotometric Determination Of Copper In Rocks"
Talanta 1993 Volume 40, Issue 4 Pages 551-555
Eluzir Moraes Pedrazzi, Ricardo Erthal Santelli

Abstract: Rocks were ground (400 mesh) and digested with HF - HClO4. The Fe(III) was removed, as the hydroxide, by treatment with NH4Cl and 18 M NH3. The Cu was pre-concentrated (~50-fold) by passage at 1.75 mL min-1 through a column (4 cm x 4 mm) of CHELEX-100 (Bio-Rad Labs., 200 to 400 mesh, Na form) followed by elution with 2.5 M HNO3 at 1.75 mL min-1. The color reagent (pH 10 to 11; 0.75 mL min-1) was a mixture of diethanolamine - carbon disulfide - Na2EDTA - aqueous 25% NH3 diluted with water. Beer's law was obeyed from 0.04 to 2.0 µg mL-1 of Cu and the precision for rocks containing 4 to 198 µg g-1 and 0.4 to 1.4 µg g-1 of Cu were 10 and 20%, respectively; an interference study is also presented. Results obtained by this method were in good agreement with certified reference rock sample values.
Copper Geological Sample preparation Spectrophotometry

"Sulfate Preconcentration By Anion-exchange Resin In Flow Injection And Its Turbidimetric Determination In Water"
Talanta 1993 Volume 40, Issue 10 Pages 1529-1534
Marina M. Santos Filha Boaventura F. Reis and Francisco J. KrugCarol H. Collins and Nivaldo Baccan,

Abstract: The flow injection system comprised a computer-controlled sliding-bar automatic injector with three commutation sections in conjunction with a spectrophotometer equipped with a 0.2 mL tubular flow cell (1.2 cm optical path). The resin column (1.5 cm x 6 mm) was machined in a Perspex block and filled with AG 1-X8 resin (200-400 mesh), converted into the nitrate form. The sample was pumped (7 ml/min) for 60 s through a sample loop (20 cm x 0.8 mm) previously loaded with 0.005% sulfate solution and through the resin column, which was then switched into the analytical path for elution (3.2 ml/min) with 0.25 M NaNO3 for 15 s. The eluted sample zone was mixed (1 ml/min) with 0.05% poly(vinyl alcohol) solution in aqueous 20% BaCl2 in a tubular helical reactor coil (100 cm x 0.8 mm) and the turbidity was monitored at 410 nm. Recoveries of standard additions to 17 rain-water samples were ~100%, and for those samples containing 0.1-2 mg/l of sulfate the RSD (n = 10) were 2%. The sample rate was 48 per h. There was negligible interference from 30 mg/l of chloride, nitrate or carbonate and a 12% decrease in absorbance from 0.05 mg/l of sulfate in the presence of 30 mg/l of phosphate.
Sulfate Rain Ion exchange Turbidimetry

"Online Sorbent Extraction, Preconcentration And Determination Of Lead By Atomic Absorption Spectrometry"
Talanta 1995 Volume 42, Issue 2 Pages 211-218
Yaneira Petit de Pe&ntilde;a*, Mercedes Gallego and Miguel Valc&aacute;rcel*,

Abstract: Skimmed milk powder and mineral reference samples were dried to a constant weight and mineralized by mixing with 14.4 M HNO3 with or without 11.2 M HCl (details given) and heating at 180-200°C until the samples dissolved and N2O fumes were given off. After cooling, the process was repeated until no N2O was evolved and a clear solution remained. The solutions were diluted with water and the mineral samples were adjusted to pH 1 with 2 M HNO3. The sample (3 ml/min) was introduced into a FIA manifold where it merged with a chelating reagent stream (0.3 ml/min) of 0.1% ammonium pyrrolidine dithiocarbamate or saturated dithizone in 0.2 M ammonia. The chelate was retained on an activated carbon minicolumn (2.5 cm x 3 mm i.d.) and the sample matrix was flushed to waste. The injection valve was switched and the column was desorbed with IBMK. The Pb was determined by AAS at 283.2 nm. Linear calibration graphs were obtained in ng/ml range (details tabulated) with detection limits of 10^-15 ng/ml for a 2 min sampling time and RSD of 2.3-3%. The effects of interferences on the method are discussed.
Lead Powder Geological Sample preparation Spectrophotometry Sample preparation

"Determination Of Palladium By Flame Atomic Absorption Spectrometry Combined Online With Flow Injection Preconcentration Using A Micro-column Packed With Activated Carbon Fibre"
Talanta 1995 Volume 42, Issue 7 Pages 921-926
Soulin Lin*, Chunsong Zheng and Guizhen Yun,

Abstract: A flow system (diagrams given) comprising a microcolumn (2.5 cm x 3 mm i.d.) packed with activated carbon fiber was used for the pre-concentration of Pd before determination by flame AAS. A similarly packed second column increased the sensitivity by doubling the analytical signal. The two columns wee in parallel in the pre-concentration mode and connected in series in the elution mode. The best pH value for retention of the metal was 3; dilute HCl was added to adjust the pH. The calibration graph was linear up to 30 ng/ml and the detection limit was 0.3 ng/ml. The RSD (n = 8) was 3.9%. Effects of interferents are tabulated. The method was applied to the determination of Pd in rock samples. Rock (0.1 g) was wetted with water in a PTFE crucible and 10 mL HF was added, heated and evaporated to dryness. Aqua regia (15 ml) was added, with gentle heating and evaporated to near dryness. HCl (2 ml) was added and the volume was made up to 100 mL with water. A portion (1 ml) was analyzed as above.
Palladium Geological Sample preparation Spectrophotometry

"Flow Injection Systems For Determination Of Trace Manganese In Various Salts By Catalytic Photometric Detection"
Talanta 1996 Volume 43, Issue 6 Pages 963-969
Takeshi Yamanea,* and Kazuo Koshinoa

Abstract: Solar salt was dissolved in water and filtered for soluble Mn determination and in water, 2 M HCl and 1.5% H2O2 with heating for 5-10 min followed by filtering for determination of total Mn. The sample containing 0.85 M NaCl was injected into a carrier stream (0.8 ml/min) at water. The stream merged with reagent streams (0.5 ml/min) of 0.26 mM 3,4-dihydroxybenzoic acid/0.75% H2O2 and 1 M sodium carbonate solution. The merged streams passed through a reaction coil (5 m x 0.5 mm i.d.) in a water bath at 40°C and the absorbance was measured at 480 nm. The same system was also used with an online separation step. The sample was injected into a carrier stream of 0.15 M sodium tartrate/4.5 mM tartaric acid/0.3 M NaCl which passed to a borosilicate glass column (7 cm x 4 mm i.d.) packed with 15.5 µm strong cation exchange resin before merging with the reagent streams as above. Calibration graphs were linear for 2-15 ppb Mn and 0-15 ppb Mn in the absence and presence of online separation, respectively, with corresponding detection limits of 2 ppb and 0.5 ppb. RSD (n = 5) was 0.9% for 8 ppb Mn without online separation and 1.4% (n = 5) for 7 ppb Mn.
Manganese Inorganic compound Ion exchange Spectrophotometry

"Simultaneous Spectrophotometric Determination Of Nitrite And Nitrate By Flow Injection Analysis"
Talanta 1996 Volume 43, Issue 7 Pages 1009-1018
M. J. Ahmeda, C. D. Stalikasa, S. M. Tzouwara-Karayannia and M. I. Karayannisa,*

Abstract: Meat products, flour, soil, beer and cheese were prepared and digested by the AOAC method ['Official Methods of Analysis of the Association of Official Analytical Chemists', Helrich (Ed.), Association of Official Analytical Chemists, Arlington, VA, USA, 1990]. The digests were filtered and the filtrate or filtered water was diluted with 0.4 M NH4Cl. The prepared samples or standards were injected into a carrier stream (0.4 ml/min) of 0.4 M NH4Cl, the stream was split into two and one stream passed through a glass reaction column (2 cm x 3 mm i.d.) packed with copper particles and a reduction column (10 cm x 3 mm i.d.) packed with copperized cadmium granules. The reduced stream merged with a reagent stream (1 ml/min) of 7.24 mM 3-nitroaniline/3.86 mM N-(1-naphthyl)- ethylenediamine dihydrochloride (1:5), the resulting stream passed through a reaction coil (50 cm) and the absorbance was measured at 535 nm. The second part of the stream by-passed the reduction columns, merged with the reagent stream and the absorbance was measured. Calibration graphs were linear for 0.01-2.2 µg/ml of nitrite and 0.1-3.5 µg/ml of nitrate with detection limits of 1 ng/ml and 10 ng/ml, respectively. The RSD (n = 5) were 0.1-2% over the calibration range for nitrate and nitrite. The permissible levels of interfering ions are tabulated.
Nitrate Nitrite Environmental Beer Cube Food Environmental Meat Sample preparation Spectrophotometry

"Determination Of Nanogram Levels Of Zirconium By Chelating Ion Exchange And Online Preconcentration In Flow Injection UV-visible Spectrophotometry"
Talanta 1997 Volume 44, Issue 3 Pages 319-326
Rajesh Purohit and Surekha Devi*

Abstract: Sample was subjected to online pre-concentration (diagram of continuous-fold manifold given) at 2 ml/min on microcolumns (4 cm x 2 mm i.d.) containing resins based on 8-hydroxyquinoline, resorcinol or hydroquinone and formaldehyde, furfuraldehyde or benzaldehyde as cross-linking agents (cf., Ibid., 1991, 38, 753). Detection was at 535 nm using Xylenol Orange as reagent. The chelated Zr(IV) was eluted from the columns with 20 µL 2 M HCl followed by acetate buffer. The method was suitable for determination of Zr in the presence of Cu(II), Ni(II), Pb(II), Zn(II), Cd(II), Fe(II), Mn(II), Al(III), Cr(VI), Mo(VI), Th(IV), V(V), Ce(IV), VO22+ and Ti(IV). Calibration graphs were linear for 0.5-2.5 µg/ml Zr for a 5 mL sample and the detection limit was 10 ng/ml. RSD were 0.8-2.65%. Separations of Zr, Ti and Th were also carried out on columns (10-18 cm x 7 mm i.d.) packed with the resins with a flow rate of 1 ml/min. Recoveries were 99.2-102.8%.
Zirconium Ion exchange Spectrophotometry

"Second-order Data By Flow Injection Analysis With Spectrophotometric Diode-array Detection And Incorporated Gel-filtration Chromatographic Column"
Talanta 1997 Volume 44, Issue 4 Pages 585-591
Iben Ellegaard Bechmann

Abstract: A model system with blue dextran, potassium hexacyanoferrate(III) and heparin as analytes was used to generate second-order FIA data. The system incorporated a gel-filtration column (2.5 cm x 16 mm i.d.) packed with Sephadex G-25 Superfine. Photodiode array detection was at 220-594 nm with scanning at 1 s intervals for 75 s, starting 20 s after injection. The tri-linear parallel factor analysis (PARAFAC) algorithm (Smilde et al., J. Chemom., 1994, 8, 21) c ombined with multiple linear regression and tri-linear partial least-squares regression (tri-PLS; Bro, Ibid., 1996, 10, 47) were used for data processing. The prediction abilities of the two methods were satisfactory for two-component mixtures and the detection of unknown interferents. The tri-PLS method was slightly better.
Iron(3+) hexacyanide Dextran Heparin Spectrophotometry

"Flow Injection Spectrophotometric Determination Of Cyanide By The Phenolphthalein Method"
Talanta 1997 Volume 44, Issue 4 Pages 545-551
Amin T. Haj-Hussein*

Abstract: Aqueous sample (50 µL) was injected into a carrier stream of 1 mM NaOH which merged with premixed streams of 0.3 mM phenolphthalin and 0.2 M carbonate buffer of pH 10.3. The flow passed through a column (6 cm x 1.4 mm i.d.) packed with 80 mg CuS particles (0.8-1.2 mm) where phenolphthalein was produced, and then to a detector where the absorbance was measured at 552 nm. The optimal flow rate was 1.08 ml/min. The calibration graph was linear for 0.6-4.3 ppm cyanide and the RSD were ~1%. The detection limit was 0.1 ppm. Interferences were investigated. The method was applied to well water. Recoveries were 98.7-101.5%.
Cyanide Well Spectrophotometry

"Flow Injection Determination Of Lead And Cadmium Traces With Graphite Furnace Atomic Absorption Spectrometry"
Talanta 1997 Volume 44, Issue 5 Pages 867-875
M. Colognesi, O. Abollino, M. Aceto, C. Sarzanini and E. Mentasti*

Abstract: Natural or potable water sample, 10 mM Tiron solution (1,2-dihydroxy-3,5-benzenedisulfonic acid) and ammonium borate buffer of pH 9 were loaded at 1 ml/min into a pre-concentration manifold (diagram given) and pumped through a column (1.5 cm x 3.9 mm i.d.) of macroporous anion-exchange resin (AGMP-1; BioRad, 100-200 mesh, chloride form). The bound Pb and Cd were eluted with 0.1 M HCl and the eluate was collected in to a sampling cup for GFAAS using a matrix modifier of NH4H2PO4/magnesium nitrate. The program details are tabulated. Pb and Cd were determined at 283.3 nm and 228.8 nm, respectively. Recoveries were 92.7±0.4% for Pd and 28±1% for Cd. Using a batch method, Cd recoveries were higher. Detection limits were 9 and 7 ng/l for Pb and Cd, respectively, for a pre-concentration ratio of 5O. No calibration data are given. Interferences and the effect of Tiron purity were investigated.
Cadmium Lead Environmental Water Spectrophotometry

"Flow Injection Determination Of Lead And Cadmium Traces With Graphite Furnace Atomic Absorption Spectrometry"
Talanta 1997 Volume 44, Issue 5 Pages 867-875
M. Colognesi, O. Abollino, M. Aceto, C. Sarzanini and E. Mentasti*

Abstract: Natural or potable water sample, 10 mM Tiron solution (1,2-dihydroxy-3,5-benzenedisulfonic acid) and ammonium borate buffer of pH 9 were loaded at 1 ml/min into a pre-concentration manifold (diagram given) and pumped through a column (1.5 cm x 3.9 mm i.d.) of macroporous anion-exchange resin (AGMP-1; BioRad, 100-200 mesh, chloride form). The bound Pb and Cd were eluted with 0.1 M HCl and the eluate was collected in to a sampling cup for GFAAS using a matrix modifier of NH4H2PO4/magnesium nitrate. The program details are tabulated. Pb and Cd were determined at 283.3 nm and 228.8 nm, respectively. Recoveries were 92.7±0.4% for Pd and 28±1% for Cd. Using a batch method, Cd recoveries were higher. Detection limits were 9 and 7 ng/l for Pb and Cd, respectively, for a pre-concentration ratio of 5O. No calibration data are given. Interferences and the effect of Tiron purity were investigated.
Cadmium Lead Environmental Water Spectrophotometry

"Equilibrium And Kinetic Properties Of A Fast Iminodiacetate Based Chelating Ion Exchanger And Its Incorporation In A FIA ICP-AES System"
Talanta 1997 Volume 44, Issue 6 Pages 1037-1053
Payman Hashemi* and &Aring;ke Olin

Abstract: Chelating ion-exchangers based on cross-linked agarose (Novarose; Scand Inovata AB, Stockholm, Sweden) were characterized for their metal binding abilities. Material with a metal binding capacity of 55 µmol/ml showed fast adsorption and desorption of Cu(II), Cd(II), Ni(II) and Ca(II) under both batch and column modes. When incorporated in a column (0.5 cm x 6 mm i.d.) in a FIA system (diagram given) quantitative adsorption of Cu(II), Cd(II) and Ni(II) occurred at flow-rates of up to 110 ml/min. Elution was achieved with 1 mL 1 M HCl at 4 ml/min for ICP-AES detection. Calibration graphs were linear for 15-120, 45-350 and 90-700 ng Cd(II), Cu(II) and Ni(II), respectively, and the detection limits were 2, 5 and 10 ng, respectively. RSD were 1.3-2.4%. The method was applied determine Cu and Cd in tap water at a flow rate of 60 ml/min.
Cadmium(2+) Calcium(2+) Copper(II) Nickel(II) Water Spectrophotometry

"Continuous-flow System For The Determination Of Trace Vanadium In Natural Waters Utilizing Inline Preconcentration/separation Coupled With Catalytic Photometric Detection"
Talanta 1998 Volume 45, Issue 3 Pages 583-589
Takeshi Yamane*, Yoshie Osada and Miho Suzuki

Abstract: A sensitive and rapid method is presented for the determination of vanadium at ng to sub ng/mL levels in natural waters, in which inline pre-concentration/separation is directly coupled with catalytic detection of vanadaium in a flow injection system. Vanadium was adsorbed on a small column packed with Sephadex G-25 gel and desorbed with a small volume of 0.010 M HCl. The catalytic action of vanadium on the oxidation of chromotropic acid by bromate in pH 3.8 buffered media was used in the sensitive determination of V. Effective pre-concentration/separation of trace vanadium can be achieved from Fe(III), Cu(II) and a large excess of NaCl in seawater sample. A linear calibration using a 5 m sample loop was obtained for 0-2.5 ng V/mL. The limit of detection was 0.02 ng/mL and the relative standard deviation was 1.2% for 1.0 ng V/mL (n = 5). This system is rapid and sensitive and can be readily applied to river water and coastal seawater samples.
Vanadium River Sea Spectrophotometry

"Low Pressure Chromatographic Separation Of Inorganic Arsenic Species Using Solid Phase Extraction Cartridges"
Talanta 1998 Volume 47, Issue 3 Pages 787-796
Serife Yal&ccedil;in and X. Chris Le*

Abstract: Routine water analysis of arsenic species requires simple, inexpensive, rapid and sensitive methods. To this end, we have developed two methods, which are based on the use of inexpensive solid phase extraction (SPE) cartridges as low pressure chromatographic columns for separation and hydride generation atomic absorption spectrometry (HGAAS) and hydride generation atomic fluorescence spectrometry (HGAFS) for detection of arsenic. Both anion exchange and reverse phase cartridges were successfully used to separate arsenite [As(III)] and arsenate [As(V)]. The composition, concentration, and pH of eluting buffers and the effect of flow rate were systematically investigated. Speciation of inorganic As(III) and As(V) were achieved within 1.5 min, with detection limits of 0.2 and 0.4 ng/ml, respectively. Both isocratic and step gradient elution techniques were suitable for the baseline resolution of As(III) and As(V) using anion exchange cartridges. Application of the methods to the speciation of As(III) and As(V) in untreated water, tap water, and bottled water samples were demonstrated. Results from the speciation of arsenic in a standard reference material water sample using these methods were in good agreement with the certified value and with inter-laboratory comparison results obtained using HPLC separation and inductively coupled plasma mass spectrometric detection (HPLC-ICPMS).
Arsenate ion Arsenic(3+) Arsenic(5+) Arsenite Environmental Waste Water Mineral Sample preparation Fluorescence

"Spectrofluorimetric Optosensing Of Aluminum In A Flow Injection System: Determination Of The Aluminum In Dialysis Fluids And Concentrates"
Analyst 1990 Volume 115, Issue 5 Pages 575-579
Maria Rosario Pereiro Garc&iacute;a, Marta Elena D&iacute;az Garc&iacute;a and Alfredo Sanz-Medel

Abstract: Samples (1 ml) in ammonium acetate buffer solution (pH 2.5) were passed through a column containing Kelex 100 adsorbed on Amberlite XAD-7 (50 to 100 mesh) to remove Fe(III), Cu(II) and Cr(III), then at pH 5 passed through the flow cell also containing the treated resin. The fluorescence at 512 nm was measured via an optical fiber (excitation at 420 nm). The method was successfully applied to determining Al in dialysis fluids and concentrates.
Aluminum Dialysis Fluid Fluorescence

"Determination Of Chlordiazepoxide By Zinc Or Cadmium Reduction In A Continuous System Followed By Atomic Absorption Spectrometric Detection"
Analyst 1990 Volume 115, Issue 7 Pages 943-949
Rosa Montero, Mercedes Gallego and Miguel Valc&aacute;rcel

Abstract: An indirect flow injection analysis - AAS method is described for determination of chlordiazepoxide (I). A portion of powdered tablets (15 to 20 mg of I) was dissolved in ethanol, with stirring, at 40°C to 50°C for 1 h. The solution was adjusted to pH 3.5 to 5.0 with 10 mM HCl and diluted to volume A portion (200 µL) was injected into a carrier stream (H2O), which was passed through a redox column (4.5 or 8.5 cm x 1.8 mm) of Cd or Zn granules (0.5 to 1.2 mm), Cu-coated Cd granules or amalgamated Zn granules. The metal in the eluate was determined by AAS, the peak being compared with that obtained by injecting a water blank (adjusted to the same pH as the sample). From 2 to 25 µg mL-1 of I could be determined, with coefficient of variation of 1.1 to 2.8%. The sampling rate was 150 h-1. Recoveries from commercial formulations were 97.3 to 102.1%.
Chlordiazepoxide Spectrophotometry

"Determination Of L-ascorbic Acid In Fruit And Vegetable Juices By Flow Injection With Immobilised Ascorbate Oxidase"
Analyst 1990 Volume 115, Issue 10 Pages 1297-1299
Gillian M. Greenway and Peter Ongomo

Abstract: Ascorbate oxidase was immobilized on cyanogen bromide activated-Sepharose 4B and incorporated in a flow injection system with amperometric detection at a glassy carbon electrode at +0.6 V. On passage through the immobilized ascorbate oxidase a fraction of the L-ascorbic acid was converted into dehydroascorbic acid and the decrease in signal was measured. This could be directly related to the amount of L-ascorbic acid present. The calibration graph was linear over the range 0-400 ng mL-1 with a correlation coefficient of 0.9994. The detection limit (2s) in phosphate buffer (0.08 M, pH 5.5) was 4.0 ng mL-1. The relative standard deviation for a 200 ng mL-1 standard was 1.0% (n = 10) and the sampling throughput was 30 samples h-1. The method was used for the simple and rapid determination of L-ascorbic acid in fruit and vegetable juice.
l-Ascorbic acid Fruit Vegetable Amperometry Electrode

"Selective Determination Of Triton-type Non-ionic Surfactants By Online Clean-up And Flow Injection With Spectrophotometric Detection"
Analyst 1990 Volume 115, Issue 5 Pages 609-612
M. Eugenia Le&oacute;n-Gonz&aacute;lez, M. Jes&uacute;s Santos-Delgado and Luis M. Polo-D&iacute;ez

Abstract: An aqueous sample (100 µL) containing Triton-type surfactants was passed through either an ion-exchange column at 0.6 mL min-1 (Amberlite IRA-904 cation exchange or IR-120 anion exchange) to remove interfering ionic surfactants, or an Amberlite XAD-4 adsorption resin followed by elution of I with 1 mL of ethanol. Alizarin fluorine blue was released into the acetate buffer stream (pH 4.5, 1.2 mL min-1) to mix with the column outflow before spectrophotometric determination at 432 nm. Beer's law was obeyed from 0.2 to 12.0 mg L-1 and 2.0 to 120 µg L-1 of such compounds. The method was compared with the picrate batch and picrate flow injection methods.
Surfactants, non ionic Triton X-100 Ion exchange Spectrophotometry

"Flow Injection Spectrophotometric Determination Of The Biuret Content In Urea Fertilizers"
Analyst 1990 Volume 115, Issue 3 Pages 319-321
Joanna Szpunar-Lobiska, Marek Trojanowicz and Liliana Ilcheva

Abstract: Flow injection systems are described (with diagrams). Fertilizer solution (50 µL) was injected into water carrier stream (0.7 mL min-1) and the stream was passed through a cation-exchange column (2 cm x 3 mm) packed with Dowex 50-X8 (100 to 200 mesh). The solution was mixed with 0.1 M sodium tartrate in 0.25 M NaOH (2.1 mL min-1) and 0.01 M CuSO4 in acidified water (1.4 mL min-1) and the absorbance was measured at 550 nm. Calibration graphs of biuret in the sample were rectilinear up to 5.0 mg mL-1; coefficient of variation were 1.2 to 2.5%. Recoveries were 98.9 to 104.5%. The only interferent, NH3, was removed with the ion-exchange column. Results agreed well with those by conventional methods.
Biuret Commercial product Ion exchange Spectrophotometry

"Simultaneous Determination Of Trace Amounts Of Iron(III) And Titanium(IV) By Flow Injection With Spectrophotometric Detection"
Analyst 1990 Volume 115, Issue 4 Pages 431-434
Shoji Kozuka, Kenichi Saito, Koichi Oguma and Rokuro Kuroda

Abstract: Powdered silicate rock sample was fused with Li2CO3 - H3BO3 (1:1) and the melt was dissolved in 1 M HCl. The solution was injected simultaneously into a carrier stream of 1 M HCl at 2 mL min-1 at two inlet points separated by a Ag reductor column that reduced Fe(III) to Fe(II). The stream was merged with a reagent solution of 0.5% disodium 1,2-dihydroxybenzene-3,5-disulfonate in acetate buffer, pH 4.9, at 2.0 mL min-1 and monitored at 430 nm. The absorption of the first peak represented the total Fe(III) and Ti(IV) content and that of the second, the Ti(IV) concentration. The method was applied in the analysis of reference materials, the results obtained agreed closely with certified values with mean coefficient of variation of 1.0 and 0.87% for Fe and Ti respectively. There was no interference.
Iron(III) Titanium(IV) Silicate Spectrophotometry

"Spectrophotometric Or Coulometric Determination Of Nitrate With An Electrochemical Reductor Using Flow Injection"
Analyst 1990 Volume 115, Issue 4 Pages 425-430
Ryuji Nakata, Minoru Terashita, Akihiko Nitta and Keiko Ishikawa

Abstract: The flow-through column electrode, with Cu and Cd deposited on glassy carbon beads, as described previously by Nakata (Fresenius Z. Anal. Chem., 1984, 317, 115) was used. The NO3- was reduced to NO2- at -0.85 to -1.05 V vs Ag - AgCl in NH4OH buffer, pH 10.0. The NO2- was determined by conventional colorimetry with a detection limit of 0.7 µm and a coefficient of variation (n = 10) of 0.52% for 10 µm. By using a column electrode with Ag deposited on the grains, as an O2 scrubber at -0.8 V, before the Cu - Cd electrode, the NO3-1 could be determined coulometrically. The limit of detection was 2 µm with coefficient of variation (n = 10) of 1.9% for 50 µm and 3.3% for 10 µm. The method was applied in the analysis of waters, the results obtained were in close agreement with those obtained by ion chromatography.
Nitrate Coulometry Electrode Electrode Spectrophotometry

"Determination Of Urea In Serum By Using Naturally Immobilized Urease In A Flow Injection Conductimetric System"
Analyst 1991 Volume 116, Issue 4 Pages 357-360
Lourival C. de Faria, Celio Pasquini and Graciliano de Oliveira Neto

Abstract: A flow injection method was developed, aimed at the determination of urea in human serum. The system makes use of the naturally immobilized urease present in Canavalia ensiformis DC (jack bean). A column is filled with small pieces of this bean, and the sample (50 µL) containing urea passes through it carried by a 1% NaCl solution. On leaving the column the stream is merged with an alkaline reagent (0.5 mol L-1 NaOH; 0.5% disodium dihydrogen ethylenediaminetetraacetate). The ammonium ions, arising from the enzymatic reaction that occurs inside the column, are changed into the molecular form, which permeates a polytetrafluoroethylene membrane and is received in a de-ionized water acceptor stream. The ammonia ionizes causing an increase in the conductance, which is proportional to the urea content of the sample. About 40 samples can be processed in 1 h with negligible carry-over and with a relative standard deviation of 1% or less. The results are in agreement with those obtained by a standard spectrophotometric method. Aqueous 0.1% serum solution (50 µL) was injected into a carrier stream (1 mL min-1) containing aqueous 1% NaCl and passed through a jack bean (Canavalia ensoformis DC) tissue column (3 cm x 2.5 mm). The eluate was merged with a stream (1 mL min-1) of 0.5 M NaOH - 0.5% disodium dihydrogen ethylenediaminetetra-acetate then passed through a PTFE membrane into an water acceptor stream (2 mL min-1), which had been passed through an ion-exchange column. The conductance of the final solution was measured. The calibration graph [conductance vs. urea (I) concentration.] was rectilinear from 1 to 10 µg mL-1 of I; the coefficient of variation (n = 10) for 3 µg mL-1 of I was 0.8%. Sample throughput was 40 h-1. Results agreed (r = 0.987) with those obtained by a standard spectrophotometric method (Sampson and Baird, Clin. Chem., 1979, 25, 1721).
Urea Serum Human Conductometry Ion exchange

"Shipboard Flow Injection Method For The Determination Of Manganese In Seawater Using In-valve Preconcentration And Catalytic Spectrophotometric Detection"
Analyst 1991 Volume 116, Issue 7 Pages 707-710
I. Ya. Kolotyrkina, L. K. Shpigun, Yury A. Zolotov and G. I. Tsysin

Abstract: Sample was applied to a micro-column (1 cm x 2.5 mm) of DETATA fibrous sorbent (H+ form; cf. Tsysin et al., Zh. Neorg. Khim., 1990, 34, 960) and the Mn adsorbed was eluted with 0.5 M HCl or HNO3. The eluate was mixed with 10 mM KIO4 in phosphate buffer solution and NN-diethylaniline in dilute HCl amd the increase in absorbance at 470 nm was recorded. Preconcentration times of 10 s to 10 min allowed determination of 20 µg L-1 to 10 ng L-1 of Mn. The coefficient of variation were 5 to 8% and a sampling rate of 15 h-1 was achieved. Recoveries of 50 ng L-1 to 10 µg L-1 of Mn were 97 to 118%. The method was applied to the direct shipboard measurement of Mn in deep seawater samples.
Manganese Sea Spectrophotometry

"Separation And Determination Of Trace Amounts Of Zinc And Cadmium By Online Enrichment In Flow Injection Flame Atomic Absorption Spectrometry"
Analyst 1991 Volume 116, Issue 8 Pages 825-830
Rajesh Purohit and Surekha Devi

Abstract: The preparation and characterization of tercopolymeric chelating resins, incorporating quinolin-8-ol and resorcinol - hydroquinone, are described. The resins were applied for pre-concentration. in the determination of Zn and Cd by flow injection flame AAS. A column (2 cm x 2 mm) containing the resin was incorporated into a flow injection manifold (described with diagram). Sample solution was passed through the column and Zn and Cd were eluted (3 mL min-1) with 1 M HNO3 (50 µL). Zinc and Cd were determined at 213.9 and 228.8 nm, respectively, by flame AAS. The detection limits were 1 ng mL-1. The average coefficient of variation (n = 6) were between 1.5 and 1.9% with the various resins.
Cadmium Zinc Spectrophotometry

"Determination Of Cobalt In Two Glasses By Atomic Absorption Spectrometry After Flow Injection Ion-exchange Preconcentration"
Analyst 1991 Volume 116, Issue 11 Pages 1141-1144
M. C. Vald&eacute;s-Hevia y Temprano, J. P&eacute;rez Paraj&oacute;n, M. E. D&iacute;az Garc&iacute;a and A. Sanz-Medel

Abstract: Ground glass (0.5 g) was digested with concentrated HNO3 - concentrated HCl04 - HF (details given) and the digest was treated with HCl, boric acid, NaOH and sodium citrate. After dilution with 0.1 M ammonium acetate - HCl buffer solution of pH 2.7 (buffer A), a 1 mL portion of the solution was injected into a carrier stream (0.5 mL min-1) of buffer A and passed through a reaction coil (3 ml). The mixture was merged with a second carrier stream (2.5 mL min-1) of 1 M NH3 - NH4Cl buffer solution of pH 8.5 and passed sequentially through a reaction coil (5 m) and a minicolumn (10 cm x 3 mm) loaded with Chelex-100. After 5 to 6 min, 200 µL of 5 M HNO3 was injected into the system to elute the Co directly into the nebulizer of the spectrometer. A schematic diagram of the flow manifold is given; operating conditions are tabulated. The calibration graph was rectilinear for 1.2 µg mL-1 of Co; the detection limit was 20 ng mL-1. For 0.5 µg mL-1 of Co, the coefficient of variation (n = 10) was 1.5%. The detection limit was 4-fold better than that obtained by direct aspiration without pre-concentration.
Cobalt Commercial product Sample preparation Ion exchange Spectrophotometry

"Determination Of Cobalt In Two Glasses By Atomic Absorption Spectrometry After Flow Injection Ion-exchange Preconcentration"
Analyst 1991 Volume 116, Issue 11 Pages 1141-1144
M. C. Vald&eacute;s-Hevia y Temprano, J. P&eacute;rez Paraj&oacute;n, M. E. D&iacute;az Garc&iacute;a and A. Sanz-Medel

Abstract: Ground glass (0.5 g) was digested with concentrated HNO3 - concentrated HCl04 - HF (details given) and the digest was treated with HCl, boric acid, NaOH and sodium citrate. After dilution with 0.1 M ammonium acetate - HCl buffer solution of pH 2.7 (buffer A), a 1 mL portion of the solution was injected into a carrier stream (0.5 mL min-1) of buffer A and passed through a reaction coil (3 ml). The mixture was merged with a second carrier stream (2.5 mL min-1) of 1 M NH3 - NH4Cl buffer solution of pH 8.5 and passed sequentially through a reaction coil (5 m) and a minicolumn (10 cm x 3 mm) loaded with Chelex-100. After 5 to 6 min, 200 µL of 5 M HNO3 was injected into the system to elute the Co directly into the nebulizer of the spectrometer. A schematic diagram of the flow manifold is given; operating conditions are tabulated. The calibration graph was rectilinear for 1.2 µg mL-1 of Co; the detection limit was 20 ng mL-1. For 0.5 µg mL-1 of Co, the coefficient of variation (n = 10) was 1.5%. The detection limit was 4-fold better than that obtained by direct aspiration without pre-concentration.
Cobalt Commercial product Sample preparation Ion exchange Spectrophotometry

"Universal Chemiluminescence Detection Using The Luminol Reaction And The Displacement Ion Effect"
Analyst 1991 Volume 116, Issue 12 Pages 1227-1230
Bolei Yan, Paul J. Worsfold and Kevin Robards

Abstract: The stoicheiometric displacement of Cu2+ from a strongly acidic ion-exchange column containing Dowex 50 W and subsequent detection by its catalytic effect on the chemiluminescent luminol reaction was used in a universal detection scheme for ions in solution Optimum reagent concentration. and flow rates permitted the detection of µg L-1 amounts of mono-, di- and tervalent cations, counter anions and weak acids. In conjunction with flow injection, the method was sensitive and reproducible. The detection technique was compatible with LC provided that a mobile phase of low ionic strength was used.
Chemiluminescence LC Ion exchange

"Flow Injection Determination Of Triton X-100 With Online Solid-phase Extraction"
Analyst 1992 Volume 117, Issue 4 Pages 767-771
Charles Moeder, Nelu Grinberg, Holly J. Perpall, Gary Bicker and Patricia Tway

Abstract: Triton X-100 was determined in the presence of a quinoline derivative in a carrier solution comprising 5 mM KH2PO4 (pH 2.0) and isobutanol - 50% acetonitrile (13:7) on a column (25 cm x 4.6 mm) of Partisil 10 SCX with detection at 276 nm. The detection limit was 0.005 mg mL-1 with a coefficient of variation of ~0.2% (n = 8) for 16.73 mg mL-1. A simple and rapid method for the determination of Triton X-100 in the presence of quinoline derivatives is described. The method involves flow injection with online cation-exchange solid-phase extraction The carrier consists of a mixture of 5 mmol L-1 aqueous KH2PO4 (pH 2.0) and 1:1 volume iso-BuOH-MeCN in the proportion 65 + 35, v/v Under these conditions, Triton X-100 elutes unretained, while the quinoline derivatives are retained on the extractor. Authentic samples are analyzed by this method, with good precision and reproducibility.
Triton X-100 Ion exchange Spectrophotometry Sample preparation

"Selective Spectrophotometric Determination Of Trace Amounts Of Chromium(VI) Using A Flow Injection System With A Microcolumn Of Zirconium(IV) Oxide Modified Silica Gel"
Analyst 1992 Volume 117, Issue 6 Pages 1029-1032
Carlos R. M. Peixoto, Yoshitaka Gushikem and Nivaldo Baccan

Abstract: A microcolumn (2 cm x 3 mm) packed with ZrO2 coated on a silica gel surface was activated with 0.1 M HNO3 (1.7 mL min-1) for 20 s. A Cr(VI) solution (pH 3 ) was passed through the column for 1 to 6 min (3.4 mL min-1), the column was washed with 1 mM HCl (2 mL min-1) for 10 s and Cr(VI) was eluted in a reversed flow (2 mL min-1) with 0.1 M tris(hydroxymethyl)methylamine. A 0.05% solution of 1,5-diphenylcarbazide previously mixed with 0.8 M HNO3 was reacted with Cr(VI) in the flow solution The absorbance of the complex was measured at 540 nm. Coefficients of variation were 2.4% (n = 10). Interference was observed for SO32- and PO43-, resulting in an incomplete separation of Cr(VI). The method was applied to natural water. Zirconium(IV) oxide coated on a silica gel surface is effective for extracting Cr(VI) from aqueous solutions at a pH of ~3. A microcolumn packed with this material was inserted into a flow injection system for the separation and pre-concentration. of Cr(VI). By this process, a concentration. level of 2 ppb was detected with a relative standard deviation of 2.4%. Because of the high selectivity of the immobilized substrate, it was possible to determine Cr(VI) in the presence of larger amounts of other ions. The analysis was also carried out on natural water spiked with Cr(VI), and compared with a standard method.
Chromium(VI) Environmental Spectrophotometry

"Determination Of Trace Amounts Of Iron In Highly Purified Water By Ion-exchanger Phase Absorptiometry Combined With Flow Analysis"
Analyst 1992 Volume 117, Issue 9 Pages 1501-1506
Ushio Hase and Kazuhisa Yoshimura

Abstract: Water sample containing 0.01 to 2 µg L-1 of Fe was pre-concentrated at 2.5 mL min-1 for 15 min on the column and for a sample containing 1 to 10 µg L-1 pre-concentration was at 1 mL min-1 for 5 min. Iron was eluted from the pre-concentration column with carrier solution (16.6 mL of anhydrous acetic acid, 14.9 mL of NH3 solution and 25 mL of buffer solution adjusted to pH 4.2 to 4.3 with 6 M HCl) and introduced directly into the sample carrier stream (schematic diagram of flow-analysis system given). At the same time 4,7-diphenyl-1,10-phenanthrolinedisulfonate solution was introduced into the reagent carrier stream and the attenuance was measured at 550 nm; as attenuance decreased, the desorbing solution containing 4 M NaNO3 - acetone was added. Iron was determined from the calibration graph. Detection limit was 0.01 µg L-1 for 80 mL of water. Results agreed well with those obtained by electrothermal vaporization - ICP-MS. The absorbance of a colored species sorbed on an ion-exchanger was measured directly to determine trace amounts of Fe, using flow anal. The method was more sensitive than the corresponding solution-phase method by a factor of 100. For the determination of Fe in highly purified water, the sensitivity was further increased by online pre-concentration. The system blank could be reduced by passing the carrier solutions through respectively online purifying columns. After the sample had been introduced onto a small cation-exchange column, the Fe concentrated on the column was eluted with an acetate carrier solution, and then mixed with the other carrier stream which contained a pulse of 4,7-diphenyl-1,10-phenanthroline disulfonate (DPPS) reagent solution The colored Fe-DPPS complex, formed in the stream, was introduced into a flow-through cell, the light path of which had been partly filled with anion exchanger. The increase in attenuation due to the sorption of the colored complex was measured continuously. The detection limit was 0.01 µg/L, when an 80 mL water sample was used.
Iron Water Ion exchange Spectrophotometry

"Ferrocene-mediated Thermal Biosensor"
Analyst 1993 Volume 118, Issue 7 Pages 845-848
Bin Xie, Masoud Khayyami, Titus Nwosu, Per-Olof Larsson and Bengt Danielsson

Abstract: A ferrocene-mediated thermal flow injection glucose sensor was fabricated and tested. The enzyme column (15 x 1.5 mm) was constructed of Pt foil in electrical contact with a poly(pyrrole)-coated reticulated vitreous carbon matrix on which glucose oxidase and ferrocene were adsorbed. The electrochemical reaction was sustained by applying a voltage between the enzyme column (working electrode) and Pt wires (counter electrode) inserted into silicone-rubber tubing at the ends of the column. Electrochemically generated ferricinium ions oxidized the reduced flavin adenine dinucleotide (cofactor of glucose oxidase). The reduced ferrocene was subsequently re-oxidized on the working electrode surface. The thermal signal generated by the redox reaction was measured. The calibration graph was rectilinear for 20 mM glucose.
Glucose Electrode Electrode Sensor

"Determination Of Trace Amounts Of Cobalt By Flow Injection With Spectrophotometric Detection"
Analyst 1994 Volume 119, Issue 7 Pages 1553-1556
Krystyna Pyrzynska, Zofia Janiszewska, Joanna Szpunar-Lobinska and Merek Trojanowicz

Abstract: A flow injection system featuring a glass microcolumn (2 cm x 2 mm i.d.) packed with alumina was used to pre-concentrate Co online as cobalt-nitroso-R-salt. Elution was effected with 0.1 M NaOH. Detection was at 520 nm with use of a Hewlett-Packard Model 8452A spectrophotometer. The detection limit for a 10 min pre-concentration was 3.5 ng/ml and the RSD at 20 ng/ml was 3.1%. The main interference was from Cu(II) which can be removed as sulfide. The method was used to determine Co in oriental tobacco leaves and pyrite ore certified reference materials.
Cobalt Leaves Pyrite Spectrophotometry

"Chemiluminescence Determination Of Proteases By Flow Injection Using Immobilized Isoluminol"
Analyst 1995 Volume 120, Issue 1 Pages 117-120
Robert Edwards, Alan Townshend and Barry Stoddart

Abstract: The enzyme was dissolved in 0.08 M Na2B4O7.10H2O/0.25 M KCl buffer of pH 9.41. The solution was further diluted with 0.1 M NaHCO3/1 M KCl buffer of pH 8.47 (buffer A) and kept at 30°C. A portion (25 µL) of the resulting solution was injected into a carrier stream (0.9 mL/min) of buffer A, maintained at 30°C, and passed through a mini-column (2.5 cm x 3 mm i.d.) containing immobilized isoluminol (prepared by coupling a tripeptide-isoluminol derivative to Affi-gel 10; details given) at 30°C. After passing through the column, the solution was mixed with a 1 µg/mL of Co(II) solution in 0.1 M NaHCO3 (0.9 mL/min) at 30°C. The resulting solution was mixed with an ice-cold solution (0.9 mL/min) of 10 µM H2O2 in 0.1 M NaHCO3 and the chemiluminescence produced was measured. The method was applied to α-chymotrypsin (I), trypsin (II) and a commercial protease (III). Calibration graphs were linear from 0.0005-0.41, 0.04-4 and 0.002-4 mg/L of I, II and III, respectively; the detection limits were 0.27, 40 and 2 µg/L, respectively. The RSD (n = 8) for 0.1 mg/L of I was 2.7%. The throughput was 7.5 samples/h.
Enzyme, chymotrypsin Trypsin Enzyme, protease Chemiluminescence

"Application Of Flow Injection Spectrophotometry To The Determination Of Dissolved Iron In Seawater"
Analyst 1995 Volume 120, Issue 1 Pages 201-206
Irina Ya. Kolotyrkina, Lilija K. Shpigun, Yury A. Zolotov and Alexander Malahoff

Abstract: Two flow injection methods are described. In the first method, streams of acidified seawater and 1 M ammonium acetate were mixed and the resulting solution was pumped through a microcolumn (1 cm x 2.5 mm i.d.) packed with diethylenetriamine sorbent for 3-10 min. After washing the column with water, elution was effected by pumping a carrier stream of 0.5 M HCl through the column for 80 s. The column eluate was mixed with a reagent stream of 1 mM p-phenetidine and 9.4 mM o-phenanthroline and subsequently with a second reagent stream of 1 M ammonium acetate and 9 mM NaIO4. The mixture was passed through a reaction coil maintained at 40°C and the absorbance was measured at 540 nm. The detection limit was 0.05 µg/l of Fe. The RSD (n = 4) was 2.4-8.1%. Recoveries were 103-110%. In the second method, 300 µL 0.01 M N,N-dimethyl-p-phenylenediamine were injected into a carrier stream of Fe-depleted acidified seawater and mixed with the acidified seawater sample stream. The resulting solution was mixed with a reagent stream of 0.12% H2O2 in 2 M ammonium acetate buffer and the absorbance was measured at 554 nm. The detection limit was 0.03 µg/l of Fe. The RSD (n = 4) was 1.8-6%. Recoveries were 98-105%.
Iron Sea Spectrophotometry

"Online Preconcentration Of Silver On A Sulfhydryl Cotton Microcolumn And Determination By Flow Injection Atomic Absorption Spectrometry"
Analyst 1995 Volume 120, Issue 7 Pages 1911-1915
M. M. G&oacute;mez G&oacute;mez, M. M. Hidalgo Garc&iacute;a and M. A. Palacios Corvillo

Abstract: A flow injection AAS method for Ag determination in water is described. The sample (15 ml) was adjusted to pH 1.5-2 with HNO3. It was then pumped into a carrier stream (3 ml/min) of 0.05 M HNO3 and passed through a column (7 cm x 1.5 mm i.d.) packed with sulfhydryl cotton fiber (pre-concentration time 5 min). The adsorbed Ag was eluted from the column by injecting 50 µL of 0.2 M KCN into the HNO3 carrier stream (1 ml/min) and was determined by AAS at 328.1 nm using an air/acetylene flame. The calibration graph was linear from 0-50 µg/l of Ag; the detection limit was 1 µg/l. The RSD (n = 5) for 10 µg/l of Ag was 3.5 %. The throughput was 9 samples/h. Recoveries of Ag were 98-108%. The method was applied to tap water.
Silver Water Spectrophotometry

"Flow Injection Spectrophotometric Determination Of Uranium With In-valve Ion-exchange Column Preconcentration And Separation"
Analyst 1995 Volume 120, Issue 8 Pages 2107-2110
Kate Grudpan, Saisunee Laiwraungrath and Ponlayuth Sooksamiti

Abstract: The sample solution was passed (1-4 ml/min) through a column (6 cm x 3.2 mm i.d.) of Duolite C-225(H) resin (pre-treated with 6 M HCl) positioned in the injection valve of the flow injection manifold. The column was washed with water and elution of U was effected by passing 1 M HCl (4 ml/min) through the column. The column eluate flowing from the injection valve was merged with a stream (8 ml/min) of 1 M triethanolamine buffer of pH 8 containing 0.7% 1,2-cyclohexanediaminetetraacetic acid and with a reagent stream (8 ml/min) of 0.02% 4-(2-pyridylazo)resorcinol in 0.1 M NaOH. The merged streams were passed through a glass bead column (10 cm x 3.2 mm i.d.) and the absorbance of the colored solution was measured at 530 nm. A diagram of the manifold used is given. The calibration graph was linear up to 7 µg of U, the detection limit was 0.27 µg and the RSD (n = 12) for 2 µg of U was 2.1%. By using dual ion-exchange columns in the injection valve, a throughput of 20-25 samples/h was achieved. The method was applied to the analysis of U in rocks and water.
Uranium Geological Water Ion exchange Spectrophotometry

"Electrochemical Detection Of African Swine Fever Virus In Pig Serum With A Competitive Separation Flow Injection Analysis Immunoassay"
Analyst 1997 Volume 122, Issue 2 Pages 155-159
Matthias Stiene and Ursula Bilitewski

Abstract: Pig serum was diluted 50-fold with PBS containing 0.05% Tween 20. A portion (1 ml) of the resulting solution was incubated with 50 ng biotinylated virus protein VP73 (preparation described) and 250 ng horse-radish peroxidase-labelled mAb 18BG3 (Ingenasa) for 25 min. A portion of the reaction mixture was injected into a carrier stream of 0.1 M phosphate buffer of pH 5.5 (buffer A) and passed through a column of biotinylated glass beads coated with streptavidin (preparation described) where the immunological complex formed during the incubation reaction was trapped. The peroxidase activity of the captured labelled antibodies was determined by passing a solution of H2O2 and hydroquinone (each 2 mM) in buffer A through the column and detecting the enzymatic product amperometrically at a vitreous C electrode at -100 mV vs. Ag/AgCl. The calibration graph was linear from 1-80 ng/ml mAb 18BG3 with a concentration of 50% inhibition at 6 ng/ml.
African swine fever virus Serum Pig Immunoassay Amperometry Electrode

"Spectrofluorimetric Determination Of Vitamin K3 By A Solid-phase Zinc Reactor Immobilized In A Flow Injection Assembly"
Analyst 1997 Volume 122, Issue 2 Pages 139-142
I. Gil Torr&oacute;, J. V. Garc&iacute;a Mateo and J. Mart&iacute;nez Calatayud

Abstract: The spectrofluorimetric determination of vitamin K3 (menadione) using a flow injection (FI) assembly provided with a solid-phase reactor with immobilized zinc is described. The naphthohydroquinone was produced by means of two coupled steps in the FI system: hydrolysis of the sodium sulfite derivative of the menadione in a basic medium and reduction of the generated menadione in the zinc reactor in an acidic medium. The fluorescent product was monitored spectrofluorimetrically (lambda ex 325 nm; lambda em 425 nm). The calibration graph was linear over the range 0.1-18 µg mL-1 with a reproducibility of 1.6%; the limit of detection was 0.005 µg mL-1 and the sample throughput was 70 h-1. The influence of foreign compounds was studied and the procedure was applied to the determination of vitamin K3 in three different pharmaceutical formulations. A stream of menadione sodium hydrogensulfite in aqueous 90% acetonitrile at a flow rate of 3.5 mL/min was merged with a stream of 35 mM NaOH at a flow rate of 0.3 mL/min. The merged stream was then passed through a 330 cm mixing coil before being merged with a stream of 0.08 M HCl in aqueous 40% acetonitrile at a flow rate of 0.3 ml/min. After passing through a 10 cm mixing coil, 850 µL of the resultant solution was injected into a carrier stream of aqueous 90% acetonitrile at a flow rate of 3 mL/min. The mixture was applied to a column (35 cm x 1.5 mm i.d.) of Zn particles then through a 25 cm mixing coil. Fluorescence was measured at 425 nm (excitation at 325 nm). A diagram of the manifold used is given. The calibration graph was linear from 0.1-18 µg/ml vitamin K3 (determined as menadione sodium hydrogensulfite); the detection limit was 0.005 µg/ml and RSD was 1.6% (n = 32). The throughput was 70 samples/h. The method was applied to the analysis of pharmaceuticals.
Vitamin K3 Pharmaceutical Fluorescence

"Optosensor For Cinchona Alkaloids With C18 Silica Gel As A Substrate"
Analyst 1997 Volume 122, Issue 3 Pages 283-285
Zhilong Gong, Zhujun Zhang and Xiaofeng Yang

Abstract: A sample was mixed with 5 mL 0.5 M H2SO4 then diluted to 25 mL with water. A portion (2 ml) was injected into a carrier stream of 0.1 M H2SO4 at a flow rate of 1 ml/min and passed through a flow cell packed with C18 silica gel. The fluorescence intensity of the alkaloid(s) retained on the silica gel was measured at 430 nm (excitation at 346 nm) for quinine (I) and quinidine (II) and at 436 nm (excitation at 363 nm) for cinchonine (III) and cinchonidine (IV). The calibration graphs were linear from 5-20 000 ng/ml I and II and from 200-20 000 ng/ml III and IV. The detection limits were 2.3 ng/ml for I and II and 31.6 ng/ml for III and IV. RSD were 0.9% at the 20 ng/ml level of I and II, and 1.1% at the 4 µg/ml level of III and IV (n = 7). Sample throughput was 10 samples/h. The method was successfully applied to the determination of I in pharmaceuticals and soft drinks. A flow-through optosensor for cinchona alkaloids with C18 silica gel as a substrate is proposed. The sensor is developed in conjunction with a flow injection analysis system and is based on the retention of the cinchona alkaloids on a C18 column and the enhancement of their fluorescence. The analytical performance characteristics of the proposed sensor for the detection and quantification of these alkaloids were as follows: the detection limits of quinine, cinchonine, quinidine and cinchonidine were 2.3, 31.6, 2.3 and 31.6 ng mL-1, respectively, with relative standard deviations of 0.9% for quinine and quinidine (20 ng mL-1, n = 7) and 1.1% for cinchonine and cinchonidine (4.0 µg mL-1, n =7), respectively. Most of the common species did not interfere. The recommended method has been successfully tested for determination of quinine in pharmaceutical preparations and soft drinks.
Alkaloids Quinine Cinchonine Quinidine Cinchonidine Soft drink Pharmaceutical Fluorescence Sensor

"Determination Of Trace Amounts Of Zinc In Water Samples By Flow Injection Isotope-dilution Inductively Coupled Plasma Mass Spectrometry"
Analyst 1997 Volume 122, Issue 3 Pages 233-237
Tarn-Jiun Hwang and Shiuh-Jen Jiang

Abstract: A water sample (25 ml) was adjusted to pH 4 with 5 mL 1 M ammonium acetate buffer. After a suitable amount of Zn-67 had been added, the solution was diluted to 50 mL with water. A portion (10 ml) of the resulting solution was loaded at a flow rate of 10 ml/min on to a column (5 cm x 10 mm i.d.) of SO3-quinolin-8-ol carboxy-methylcellulose. The column was washed with 0.1 M ammonium acetate buffer of pH 4; the retained Zn was eluted (3 ml/min) with 0.5 M HNO3. The eluate was analyzed by ICP-MS (details given). The Zn-66/Zn-67 isotope ratio was calculated from the peak areas of the flow injection peaks. The calibration graph was linear up to 50 ng/ml Zn-66; the detection limit was 14 pg/ml. RSD was 1.4% (n=7). The method was applied to several water CRM; the results agreed with the certified values.
Zinc-66 Zinc-67 Estuarine River Sea NRCC NASS-3 NRCC SLEW-1 NRCC SLRS-2 NRCC CASS-3 Mass spectrometry Mass spectrometry

"Fully Automatic Online Separation Preconcentration System For Electrothermal Atomic Absorption Spectrometry: Determination Of Cadmium And Lead In Seawater"
Analyst 1997 Volume 122, Issue 7 Pages 679-684
Facundo M. Fern&aacute;ndez, Jorge D. Stripeikis, Mabel B. Tudino and Osvaldo E. Troccoli

Abstract: A fully automated system for analyte separation and pre-concentration prior to ET AAS determination is described. Preconcentration is performed on a chelating resin microcolumn (Chelex-100) placed in the injection tip of the graphite furnace autosampler. A time-based computer-controlled flow injection manifold is used for column conditioning, pre-concentration and washing steps. Elution is performed in a single step by the programmable graphite furnace autosampler; both complete and partial injection of the eluate into the graphite furnace for ET AAS analysis are possible. Diagrams of the manifold used, illustrating the sequence of operations involved, are given. The system was used to determine Cd and Pb in seawater. Detection limits of 0.9 and 8 ng/l were obtained for Cd and Pb, respectively. The RSD (n = 10 or 15) were 2.7-4%.
Cadmium Lead Sea Sample preparation Spectrophotometry

"Stability Of Bromate Species Immobilized On Microcolumns Of Activated Alumina"
Analyst 1998 Volume 123, Issue 5 Pages 981-982
A. R. Elwaer, C. W. McLeod and K. C. Thompson

Abstract: Microcolumns of activated alumina (n = 30) were charged with bromate standard solution (0.5 mL, 6.0 µg L-1) and stored at 4°C in a light-tight container. Microcolumns were removed at regular time intervals (1 hour, 2 and 3 days and 1, 2, 3, 4 and 8 weeks) and bromate species were eluted and quantified by flow injection ICP-MS, Analyte recoveries were found to be quantitative (96-101%) and reproducible over the eight week period, These results indicate that for trace level determinations (µg L-1) of bromate, a microcolumn format may provide a convenient and reliable route for delivery of external calibrants and reference materials. (15 References)
Bromate Mass spectrometry

"Trace Enrichment And Determination Of Sulfate By Flow Injection Inductively Coupled Plasma Atomic Emission Spectrometry"
J. Anal. At. Spectrom. 1987 Volume 2, Issue 6 Pages 553-555
Alan G. Cox, Cameron W. McLeod, Douglas L. Miles and Jennifer M. Cook

Abstract: The sample was injected into a stream of 0.01 M HNO3, and SO42- was retained on a column (2.5 cm x 1.5 mm) of acidic alumina, from which it was eluted by injection of 0.2 mL of aqueous 2 M NH3, and carried to the ICP for determination at 180.73 nm. Residual SO42- was eluted with further NH3, and the recovery was calculated as the ratio of peak areas for replicate injections of SO42- solution with and without the alumina column in the stream. The calibration graph was rectilinear for up to 1 mg L-1 of SO42- (2 mL injections), the detection limit was 2.8 µg l-1, and the coefficient of variation (n = 7) at 10 µg L-1 and 1 mg L-1 were 7 and 0.8%, respectively. The method was applied to various natural waters (seawater was diluted two-hundredfold), with results in good agreement with those by conventional ICP-AES. The method was also applied to boiler-feed water.
Sulfate Water Sea Spectrophotometry

"Flow Injection Ion-exchange Preconcentration For The Determination Of Aluminum By Atomic Absorption Spectrometry And Inductively Coupled Plasma Atomic Emission Spectrometry"
J. Anal. At. Spectrom. 1987 Volume 2, Issue 7 Pages 699-703
M. R. Pereiro Garc&iacute;a, M. E. D&iacute;az Garc&iacute;a and Alfredo Sanz Medel

Abstract: For the pre-concentration. of Al in solution (e.g., potable waters or haemodialysis fluids), sample (1 ml) was injected into a carrier stream (1.5 mL min-1) of 50 mM 2-(N-morpholino)ethanesulfonic acid - NH3 buffer (pH 7) and passed through a mini-column of Amberlite IRA-400 (~0.108 g). The resin was washed before use to remove Al. After ~2 min, a 'plug' (75 µL) of 1 M NaOH was injected on to the column and the stripped Al was determined by flame AAS at 309.6 nm or by ICP-AES at 396.15 nm. Determination in the ng L-1 range was possible by either technique. Aluminum in serum is too tightly bound by proteins to be retained by the mini-column. For the pre-concentration. of Al in solution (e.g., potable waters or haemodialysis fluids), sample (1 ml) was injected into a carrier stream (1.5 mL min-1) of 50 mM 2-(N-morpholino)ethanesulfonic acid - NH3 buffer (pH 7) and passed through a mini-column of Amberlite IRA-400 (~0.108 g). The resin was washed before use to remove Al. After ~2 min, a 'plug' (75 µL) of 1 M NaOH was injected on to the column and the stripped Al was determined by flame AAS at 309.6 nm or by ICP-AES at 396.15 nm. Determination in the ng L-1 range was possible by either technique. Aluminum in serum is too tightly bound by proteins to be retained by the mini-column.
Aluminum Water Haemodialysis Fluid Ion exchange Spectrophotometry Spectrophotometry

"Determination Of Arsenic In A Nickel-based Alloy Using A Microwave Digestion Procedure And A Continuous-flow Hydride-generation Atomic Absorption System Incorporating Online Matrix Removal"
J. Anal. At. Spectrom. 1989 Volume 4, Issue 2 Pages 181-184
Philip G. Riby, Stephen J. Haswell and Roman Grzeskowiak

Abstract: Sample (1 g) was dissolved in HNO3 - HF in a microwave digestion unit over 1 h, and the resulting solution was passed through a Bond Elut strong cation-exchange column to remove Ni. The resulting solution was then mixed in a flow injection system with 1% NaBH4 solution in aqueous 1% NaOH followed by 4 M HCl, and the generated AsH3 was stripped by Ar in a gas - liquid separator and determined at 193.7 nm. The cation-exchange resin could be regenerated by washing with 1 M HCl. Recovery of 25 ppm of As added to low-As Ni-based alloy was 98%. The limit of detection in the final solution was 1.3 ppb of As, the calibration graph was rectilinear up to 20 ppb, and the coefficient of variation (n = 10) for 10 ppb was 3%.
Arsenic Alloy Ion exchange Sample preparation Spectrophotometry

"Flow Injection Flame Atomic Absorption Spectrometry System For The Preconcentration Of Vanadium(V) And Characterization Of Vanadium-(IV) And -(V) Species"
J. Anal. At. Spectrom. 1989 Volume 4, Issue 2 Pages 195-198
Bharti Patel, Stephen J. Haswell and Roman Grzeskowiak

Abstract: Sample solution was passed through a Bond Elut SAX (strong cation exchange) column; V(IV) was not retained, and passed straight to a flame AAS instrument. The retained V(V) was eluted with 0.5 M NaOH (pH 11), and V was determined by N2O - acetylene flame AAS at 318.5 nm. Calibration graphs for various sampling times (15, 30 or 60 s) were rectilinear in the range 0.2 to 1 µg mL-1 of V. For an initial solution containing 50 ppb of V, the coefficient of variation was 3% (n = 8).
Vanadium(IV) Vanadium(V) Ion exchange Spectrophotometry

"Chelating Resins For Online Flow Injection Preconcentration With Inductively Coupled Plasma Atomic-emission Spectrometry"
J. Anal. At. Spectrom. 1989 Volume 4, Issue 6 Pages 509-518
Xiarou Wang and Ramon M. Barnes

Abstract: A poly(dithiocarbamate) (PDTC) and a methylcarboxylated poly(ethylenimine) - poly(methylenepolyphenylene) isocyanate (CPPI) chelating resin were evaluated for the online pre-concentration. of 22 elements, with subsequent elution and detection by ICP-AES. The effect of pH on recovery of elements and of parameters, such as column length and diameter, which affect the dispersion of the analyte zone were studied. The PDTC resin works effectively at pH 8 to 10, whereas the CPPI resin chelated successfully at pH 5 to 6. Some elements could be pre-concentrated on one resin only. The PDTC resin was applied in the determination of Cu and Zn in natural and drinking water. Recovery of Cu was 98% at 20 and 50 ng mL-1, and the coefficient of variation (n = 11) was ~3% for 100 ng mL-1 of Cu.
Copper Zinc Environmental Water Spectrophotometry

"High-efficiency Low-sample-consumption Online Ion-exchange Preconcentration System For Flow Injection Flame Atomic Absorption Spectrometry"
J. Anal. At. Spectrom. 1989 Volume 4, Issue 6 Pages 543-546
Zhaolun Fang and Bernhard Welz

Abstract: The cited system was used for determination of heavy metals. Only 1.6 mL of sample solution was required for analysis, 120 samples h-1 could be analyzed, and enrichment factors of 25 to 31 were achieved for Cu, Cd and Pb. The coefficient of variation were 1.2 to 2.8%; e.g., for 100 µg L-1 of Cu the coefficient of variation was 1.5% (n = 81). The CPG/8-Q ion exchanger was used, and conical columns, short, small-bore conduits and three-dimensional disoriented reactors were used to limit the dispersion of the eluted sample zone. Low elution flow rates and high nebulizer uptake rates were used to improve nebulization efficiency. Application of the method in analysis of seawater is discussed.
Copper Cadmium Lead Metals, heavy Sea Spectrophotometry

"Liquid Chromatography With An Inductively Coupled Plasma Mass-spectrometric Detector For Simultaneous Determination Of Gold Drug Metabolites And Related Metals In Human Blood"
J. Anal. At. Spectrom. 1989 Volume 4, Issue 8 Pages 767-771
Susan G. Matz, R. C. Elder and Katherine Tepperman

Abstract: Blood plasma or serum (0.5 ml) was digested with 2.5 mL of aqueous 40% HNO3 with heating for 30 s at 700 W. The cooled digest was analyzed by ICP-MS in conjunction with a flow injection system. The mobile phase comprised water, aqueous 5% HNO3, 50 mM NH4 acetate buffer (pH 5.5) or 50 mM Tris buffer (pH 6.5). Matrix effects were significant. Detection limits were 0.2 to 0.7 ppb of Au, Zn and Cu, and calibration graphs were rectilinear up to 1000 ppb. The digests were also determined by ICP-MS after separation by HPLC on a column (15 cm x 4.6 mm) of Alltech WAX 300 anion exchanger with 20 to 200 mM Tris buffer (pH 6.5) as mobile phase or on a column (30 cm x 7.5 mm) of Bio-Sil TSK 250, with 25 mM Tris buffer (pH 7.7) as mobile phase. The HPLC - ICP-MS system was applied in the simultaneous determination of sixteen elements.
Copper Gold Zinc Plasma Human Serum Human Mass spectrometry Sample preparation

"Flow Injection Inductively Coupled Plasma Mass Spectrometry For The Determination Of Platinum In Airborne Particulate Matter"
J. Anal. At. Spectrom. 1990 Volume 5, Issue 1 Pages 75-80
Hitoshi Mukai, Yoshinari Ambe and Masatoshi Morita

Abstract: Standard solution of Pt in 0.6 M HCl and samples of particulate airborne matter (prep. described) were introduced into a flow injection system (described) incorporating a cation-exchange column (16 cm x 8 mm) of Dowex 50W-X8 (50 to 80 mesh) which was pre-washed with 3 M HCl and stabilized with 0.6 M HCl. This system was used online for trapping major matrix elements, which cause suppression of the Pt signal at m/e = 195, and Hf (which interferes spectrally) from 0.6 M HCl medium. The eluate from the column was introduced into the ICP-MS for the determination of Pt. The calibration graph was rectilinear up to 40 µg L-1 of Pt, and the coefficient of variation (n = 5) for 2 µg L-1 of Pt was ~5%. The detection limit was ~0.1 µg L-1 of Pt in solution or 5 ng g-1 in airborne particulate matter. The method was applied to the determination of Pt in samples such as vehicle exhaust particulates and roadside dust.
Platinum Exhaust Particulates Road Mass spectrometry Ion exchange

"Online Aluminum Preconcentration And Its Application To The Determination Of The Metal In Dialysis Concentrates By Atomic-spectrometric Methods"
J. Anal. At. Spectrom. 1990 Volume 5, Issue 1 Pages 15-19
M. R. Pereiro Garc&iacute;a, A. L&oacute;pez Garc&iacute;a, M. E. D&iacute;az Garc&iacute;a and A. Sanz-Medel

Abstract: The use was studied of the cation and anion exchangers Dowex 50W-X2 and Amberlite IRA-400, and of Chelex 100 and a synthetic chelating resin (Kelex 100 adsorbed on Amberlite XAD-7) for the pre-concentration. of Al with elution with various concentration. of NaOH, KOH, HCl and HNO3. The materials were packed in a mini-column inserted in a flow injection pre-concentration. manifold and Al was determined by AAS or ICP-AES. The pre-concentration. conditions were optimized and detection limits of 15 and 3 µg mL-1 were obtained with AAS and AES detection, respectively. Chelex 100 and Amberlite IRA-4 were most suitable for determination of Al in dialysis concentrates, but the latter cannot be used if the acetate concentration. is >40 mg mL-1.
Aluminum Spectrophotometry Spectrophotometry

"Elimination Of Copper Interference By Continuous-flow Matrix Isolation In The Determination Of Selenium By Flow Injection Hydride-generation Atomic Absorption Spectrometry"
J. Anal. At. Spectrom. 1991 Volume 6, Issue 2 Pages 133-138
Stephen G. Offley, Nichola J. Seare, Julian F. Tyson and Helen A. B. Kibble

Abstract: For removal of Cu from the sample solution for determination of Se by the cited technique, a mini-column (5 cm x 3 mm) of Dowex 50W-X8 strongly acidic cation-exchange resin was incorporated into the flow system. The mini-column manifold and hydride-generation manifold were made independent of each other to achieve optimum performance for each step. After removal of Cu, a 400 µL aliquot of sample solution was injected into the carrier stream (H2O) for determination of Se. Periodic regeneration of column with 1 M HCl obviated the need for repacking, without loss of resin efficiency. The method was applied to the determination of 36 and 479 µg g-1 of Se in two standard coppers. The system had a sample rate of 51 h-1, a detection limit of 2.1 ng mL-1, and a coefficient of variation (n = 12) of 1.5% at 10 ng mL-1.
Selenium Spectrophotometry

"Determination Of Ultra-trace Levels Of Metal Ions In Seawater With Online Preconcentration And Electrothermal Atomic Absorption Spectrometry"
J. Anal. At. Spectrom. 1991 Volume 6, Issue 2 Pages 119-122
V. Porta, O. Abollino, E. Mentasti and C. Sarzanini

Abstract: An on-line pre-concentration system for electrothermal atomic absorption spectrometry was developed. A miniature silica C18 column was inserted at the tip of the autosampler arm. A modification of the tubing line of the autosampler allowed either the flow of the sample through the column or the operation of the autosampler in the normal mode. The retention of the metal ions in the form of complexes on the microcolumn was achieved by using pyrrolidin-l-yl dithioformate as the complexing agent; acetonitrile was then used for the elution. The direct injection of the eluate into the graphite furnace gave high pre-concentration factors, ranging between 20 and 225, which are sufficient for the determination of Cd, Pb, Cu, Ni, Co and Fe in Antarctic sea-water. The blank level was very low and the detection limits ranged from 0.4 ng l-1(Cd) to 25 ng l-1(Fe).
Metals, heavy Sea Spectrophotometry

"Immobilized Alga As A Reagent For Preconcentration In Trace Element Atomic Absorption Spectrometry"
J. Anal. At. Spectrom. 1991 Volume 6, Issue 8 Pages 643-646
Hayat A. M. Elmahadi and Gillian M. Greenway

Abstract: Metal ions in buffer solution were injected into a carrier stream (2 mL min-1) of water in a flow injection system (diagram given). The mixture was passed through a column (5 cm x 2.5 mm) packed with the alga Selenstrum capricornutum immobilized on controlled pore glass (details given). After washing with water, the accumulated ions were released by injection of HNO3 and passed to the flame for detection by AAS. Under optimized conditions (details given), the calibration graphs were rectilinear for 5 to 45, 10 to 100, 55 to 300, 650 to 5000, 15 to 80 and 60 to 450 ng mL-1 of Cu2+, Zn2+, Co2+, Hg2+, Cd2+ and Pb2+, respectively; corresponding detection limits were 0.05, 0.2, 8, 30, 2 and 2.5 ng mL-1. The sampling rate was 20 h-1.
Trace elements Spectrophotometry

"Flow Injection Flame Atomic Absorption-spectrometric Determination Of Copper With Preconcentration On Ligand-loaded Amberlite XAD-2"
J. Anal. At. Spectrom. 1992 Volume 7, Issue 2 Pages 323-328
Abdulmagid M. Naghmush, Marek Trojanowicz and Ewa Olbrych-Sleszynska

Abstract: A sample solution containing copper was merged with a stream (2.2 mL min-1) of 1% Na2B4O7 solution (pH 8.0) directed on to a column (7 cm x 3 mm) of Amberlite XAD-2 (20 to 60 mesh) modified with catechol violet (I), 4-(2-pyridylazo)resorcinol or Eriochrome blue black R (C.I. Mordant Black 17). Copper was eluted from the column with 2 M HNO3 and the eluate was analyzed by flame AAS. The method was applied to the determination of Cu in natural water by flame AAS with pre-concentration. on a I-loaded Amberlite XAD-2 column. Calibration graphs were rectilinear for up to 2 ppb of Cu. Chelating sorbents obtained by loading a nonpolar sorbent, Amberlite XAD-2, with pyrocatechol violet (PV), 4-(2-pyridylazo)resorcinol (PAR) or Eriochrome Blue Black R were used for a time-based pre-concentration of Cu(II). The effect of pre-concentration and elution flow-rate on the detection limit and the effectiveness of Cu(II) sorption were examined Pyrocatechol violet loaded XAD-2 was employed for the determination of Cu(II) by flow injection flame atomic absorption spectrometry in natural waters at the ppb level using a pre-concentration. time of 20 min. Superior dynamic properties of PV loaded sorbent in comparison with an hydroxyquinoline chelating resin is demonstrated. The effect of the presence of alkali, alkaline earth and some transition metal ions on Cu(II) sorption was examined. Significant interference was observed for concentrations. of Ca above 50 ppm. Interference from Fe(III) can be reduced by the addition of fluoride to the pre-concentrated sample.
Copper(II) Environmental Spectrophotometry

"Determination Of Trace Metals In Concentrated Brines Using Inductively Coupled Plasma Mass Spectrometry Online Preconcentration And Matrix Elimination With Flow Injection"
J. Anal. At. Spectrom. 1993 Volume 8, Issue 7 Pages 979-981
Les Ebdon, Andrew Fisher, Howard Handley and Philip Jones

Abstract: Two chelation ion-exchange columns, an in-house (xylenol orange) one and a commercial (Metpac CC-1) one, were used for matrix elimination and online pre-concentration of the analytes (the alkaline-earth and first-row transition metals) before their determination in brines by ICP-MS with a VG Plasmaquad II instrument. Residual Na was determined by flame AAS. The method was used to determine the metals in seawater reference material NASS-3 (National Research Council of Canada). The response was linear in the range of interest (200 µg/l), and excellent agreement with the certified values was achieved. At the pH used, the in-house column retained all the alkaline-earth metals, but the transition metals were retained only slightly, so recovery was poor. The Metpac CC-1 column retained all the metals investigated and gave good precision.
Metals, trace Environmental NRCC NASS-3 Sea Mass spectrometry Spectrophotometry

"Trace Enrichment And Determination Of Gold By Flow Injection Inductively Coupled Plasma Spectrometry. 2. Inductively Coupled Plasma Mass Spectrometry"
J. Anal. At. Spectrom. 1995 Volume 10, Issue 2 Pages 89-91
M. M. G&oacute;mez G&oacute;mez and C. W. Mcleod

Abstract: Water was treated with HCl or NaCl to contain 4000 and 1000 mg/l of chloride respectively, and the solutions adjusted to a pH of 6-8 with HNO3 or NH3. Standard solutions of colloidal Au and containing 10 mg/l of humic acid were similarly prepared. Portions (8-40 ml) of the solutions were passed off-line at 4 ml/min for 2-10 min through a PTFE column (7 cm x 1.5 mm i.d.) and containing ~25 mg of sulfydryl cotton fiber. The pre-concentrated Au was eluted with three injections of 250 µL of 10 mM KCN at 1 ml/min, and analyzed using a 1300 W ICP with quadrupole MS detection (details given). Calibration graphs were linear upto 20 ng/l Au, with a detection limit of 0.19 ng/l. At 5 ng/l Au an RSD (n = 5) of 3.6% was obtained. An Au enrichment factor of 32-160 was estimated. The method was applied to mineral and natural water.
Gold Environmental Mineral Mass spectrometry

"Field Sampling Technique For The"
J. Anal. At. Spectrom. 1995 Volume 10, Issue 3 Pages 281-285
Ben Fairman, Alfredo Sanz-Medel and Phil Jones

Abstract: Samples that contained 'fast reactive' Al (FR-Al), 0.01 M acetate buffer of pH 5 and 0.005 M 8-hydroxyquinoline (HQ) in acetate buffer of pH 5 were pumped simultaneously through a sampling manifold (illustrated). The sample and buffer were subsequently mixed in a reactor coil before the addition of the 0.005 M HQ and the combined streams passed through (2-5 min) a mini-column (5 cm x 1.5 mm i.d.) packed with Amberlite XAD-2 non-ionic resin. Retained Al was eluted with 330 µL 1 M HCl and analyzed by ICP-AES and ICP-MS (operating conditions tabulated). With ICP-AES the RSD was 8% for 2 mL samples of standard solutions that contained 100 µg/l of Al. The detection limit was 10 µg/l. FR-Al levels (40.6 ± 3.2 µg/l) in tap water (total Al 229 ± 10 µg/l) of pH 8.9 were in good agreement with HPLC analyzes at pH 3 (Jones, Int. J. Environ. Anal. Chem., 1991, 44, 1) for Al(III) (43.7 ± 2.1 µg/l). Problems were however encountered with moorland waters of pH 5.4-6.7 that contained less total Al and Al(III), due to the poor sensitivity levels of the ICP-AES detection system (discussed). Data from field sampling trials measured by ICP-MS were in good agreement with Al(III) levels (tabulated) measured by HPLC. The RSD was 8% for 2 mL samples of standard solutions that contained 100 µg/l of Al with a detection limit of 1.8 µg/l.
Aluminum(III) Aluminum, total Water Moor Mass spectrometry Spectrophotometry

"Preconcentration And Determination Of Some Lanthanide Elements With Immobilized Bacteria By Flow Injection Inductively Coupled Plasma Atomic-emission Spectrometry"
J. Anal. At. Spectrom. 1996 Volume 11, Issue 2 Pages 99-106
Angel Maquieira, Hayat Elmahadi and Rosa Puchades

Abstract: Lanthanides were determined using a previously described FIA method (Anal. Chem., 1994, 66, 3632). The analytes were pre-concentrated by Spirulina plantensis bacteria dissolved in aqueous NaOH, immobilized on controlled-pore glass and packed into a methyl methacrylate mini-column (2.5 cm x 2 mm i.d.). The lanthanides were detected by ICP-AES with an Ar plasma and a cross-flow nebulizer at 3.2 bar using wavelengths of 394.91, 408.672 and 401.225 nm for La3+, Ce3+ and Nd3+, respectively. The effects of flow rate and pH on the pre-concentration is discussed. Detection limits were 9, 0.21 and 0.54 ng/ml for La(III), Ce(III) and Nd(III), respectively, with corresponding recoveries of 100.2±0.04, 105.2±0.18 and 100.1±0.2%. The method was applied to the determination of La(III) and Nd(III) in high-purity Ce(III).
Lanthanum Neodymium High purity Spectrophotometry

"Automated Online Preconcentration System For Electrothermal Atomic Absorption Spectrometry For The Determination Of Copper And Molybdenum In Seawater"
J. Anal. At. Spectrom. 1997 Volume 12, Issue 8 Pages 841-847
YU-HSIANG SUNG, ZHEN-SHAN LIU and SHANG-DA HUANG

Abstract: The operation of the flow injection manifold is illustrated diagrammatically, the operating sequence is tabulated, and a diagram of the computer-control connections is also presented. Fourteen samples can be injected per h. Online pre-concentration of the analytes is achieved by incorporation of a bypassable microcolumn of Muromac A-1 chelating resin at the tip of the AS-60 autosampler arm. A diagram of the microcolumn is presented; for the retention of Cu and Mo the resin volumes are ~7 and 4 µL and the mesh sizes are 100-200 and 200-400, respectively. Elution into the graphite furnace is effected with 50 µL of 20% (v/v) HNO3. The heating programmes are tabulated. The metals were determined in seawater by calibration with standard solutions in 0.2% HNO3 carried through the procedure; the detection limits and injection volumes for Cu and Mo were 0.009 and 0.06 µg/l and 606.9 and 200 µl, respectively. The results for Cu in three and for Mo in two seawater standard reference materials agreed well with the certified values.
Copper Molybdenum Sea Spectrophotometry

"Flow Injection Manifold For Matrix Removal In Inductively Coupled Plasma Mass Spectrometry By Solid Phase Extraction: Determination Of Al, Be, Li And Mg In A Uranium Matrix"
J. Anal. At. Spectrom. 1998 Volume 13, Issue 12 Pages 1327-1331
Paul Becotte-Haigh, Julian F. Tyson and Eric Denoyer

Abstract: A flow injection manifold, incorporating two pumps and an 8-port rotary valve, was developed for the automation of a procedure for the removal of the matrix suppression of uranium on light elements. The procedure was based on the selective retention of the uranium on a column of TRU.Spec.RTM. resin (a support material impregnated with a liquid ion-exchanger). The light elements were not retained. The uranium was removed by 0.2 mol/L ammonium oxalate solution and the column reconditioned by the passage of 25% (v/v) nitric acid. The interference of uranium, 5000 mg/L, was removed, allowing the determination of aluminum, beryllium, lithium and magnesium at concentrations. down to a few µg/L in 100 µL of sample. The sample acidity was 20% and the carrier stream was 5% with respect to nitric acid. Although higher acid concentrations. could have improved the retention of uranium, the acid concentration. was not increased to avoid degrdn. of the nickel sampling and skimmer cones. A complete anal. cycle took 4 min, including the regeneration of the column.
Aluminum Beryllium Lithium Magnesium Metal Mass spectrometry

"Determination Of Chromium(III), Titanium, Vanadium, Iron(III), And Aluminum By Inductively Coupled Plasma Atomic Emission Spectrometry With An Online Preconcentrating Ion Exchange Column"
Anal. Chem. 1986 Volume 58, Issue 13 Pages 2602-2606
Shizuko Hirata, Yoshimi Umezaki, and Masahiko Ikeda

Abstract: A method utilizing a miniature ion-exchange column of Muromac A-1 (Muromac Chemicals, Tokyo) has been developed to increase the sensitivity for aluminum, chromium(III), iron(III), titanium, and vanadium measurements by inductively coupled plasma atomic emission spectrometry (ICPAES). A sample (pH 3.8) is pumped through the column at 6.0 mL min-1, mixing with the buffer solution, and sequentially eluted directly to the nebulizer of the ICP with 2 M HCl acid at 3.0 mL min-1 by using a flow injection analysis (FIA) system. This FIA-ICP method gave signal enhancements that were 34-113 times better than for a conventional continuously aspirated system for the metals studied here. A precision of the technique is better than 5 YO relative standard deviation at the 10 µg L-1 level for aqueous standards, and the sampling rate is 17 samples h-1.
Aluminum Chromium(III) Iron(III) Titanium Vanadium Ion exchange Spectrophotometry

"Determination Of Picomolar Levels Of Cobalt In Seawater By Flow Injection Analysis With Chemiluminescence Detection"
Anal. Chem. 1987 Volume 59, Issue 14 Pages 1789-1794
Carole M. Sakamoto-Arnold and Kenneth S. Johnson

Abstract: Interfering alkaline-earth ions were separated from Co in seawater online on a column of immobilized quinolin-8-ol on Fractogel; elution of Co was with 0.05 M HCl. The eluate was mixed with reagent streams containing 0.02 M gallic acid, 0.4 M H2O2, 0.15 M NaOH and 4% methanol before chemiluminescence detection at 643 nm. The detection limit was ~8 pM, the analysis time was 8 min, and the average standard deviation (n ~ 80) was 5%.
Cobalt Sea Chemiluminescence

"Separation Of Trace Metal Complexes For Analysis Of Samples Of High Salt Content By Inductively Coupled Plasma Mass Spectrometry"
Anal. Chem. 1989 Volume 61, Issue 2 Pages 149-153
Michael R. Plantz, James S. Fritz, Fred G. Smith, and R. S. Houk

Abstract: Solutions of trace metals (Au, Bi, Co, Cr, Cu, Fe, Hg, Mo, Nb, Ni, Pt, Tl, U and V) in aqueous media of high salt content were treated with bis(carboxymethyl)dithiocarbamate reagent (prep. described) and injected into the loading solvent (0.05 M formate buffer of pH 3.25) for application to a column of Amberlite XAD-4 resin. The adsorbed complexes were eluted with aqueous 0.1 M NH3 (pH 11) and the eluate was analyzed by ICP-MS on a Sciex Elan model 250 instrument fitted with a continuous-flow ultrasonic nebulizer. Detection limits in salt-rich aqueous solution ranged from 6 ng L-1 for Bi to 80 ng L-1 for Pt. The method has been used to determine Cr, Ni and Pt in urine, and trace metals in seawater.
Chromium Nickel Platinum Sea Urine Mass spectrometry

"Characterization Of Formaldehyde And Formaldehyde-releasing Preservatives By Combined Reversed-phase Cation-exchange High Performance Liquid Chromatography With Post-column Derivatization Using Nash's Reagent"
Anal. Chem. 1990 Volume 62, Issue 14 Pages 1397-1402
William Russell Summers

Abstract: Preservative solution (50%) was injected on to a polymeric reversed-phase column (15 cm x 4.6 mm) of PRP-1 (5 µm), with gradient elution with water, acetonitrile and diaminopropionic monohydrochloride solution (details given), the eluate was derivatized with Nash reagent (2 M ammonium acetate - 0.02 M penta-2,4-dione - 0.03% acetic acid) and the absorbance and fluorescence of derivatives was measured at 410 and 510 nm, respectively. The method is labour-saving and permits the simultaneous analysis of preservatives and formaldehyde. The detection limit was ~400 ppb with rectilinear dynamic ranges of two orders of magnitude. The coefficient of variation was ~0.5%.
Formaldehyde Preservatives HPLC Ion exchange Spectrophotometry Fluorescence

"Liposome Flow Injection Immunoassay: Implications For Sensitivity, Dynamic Range, And Antibody Regeneration"
Anal. Chem. 1990 Volume 62, Issue 23 Pages 2587-2593
Laurie Locascio-Brown, Anne L. Plant, Viola Horvath, and Richard A. Durst

Abstract: We have developed a liposome-based flow injection immunoassay (FIIA) system for quantitation of a clinical analyte, theophylline. With very minor changes in assay format, this procedure can also be used for the quantitation of anti-theophylline. Automated sequential analyzes were performed at room temperature with picomole sensitivity and a day-to-day coefficient of variation of less than 5% for aqueous solutions. The system components include liposomes that contain fluorophores in their aqueous centers and an immobilized-antibody reactor column. The immunoreactor was regenerated hundreds of times over 3 months of continuous use with no measurable loss of antibody activity. The two assay formats studied produced distinct dynamic ranges for their respective analytes. The special advantages of using flow injection analysis for immunoassays and of using liposomes in FIIA are discussed.
Theophylline Immunoassay

"Thermal-gradient Micro-bore Liquid Chromatography With Dual-wavelength Absorbance Detection"
Anal. Chem. 1991 Volume 63, Issue 6 Pages 568-574
Curtiss N. Renn and Robert E. Synovec

Abstract: A single fiber-optic two-wavelength detector is described for remote sensing in thermal-gradient microbore LC (TGMLC). Theoretical relationships are derived relating changes in the refractive index of the LC mobile phase to aperture-limited absorbance measurements. The use of the detector system was illustrated by the reversed-phase separation of unleaded gasoline on a C18 column, with a temperature gradient of 25°C to 150°C over 30 min, methanol - water as the mobile phase and detection at 230 and 295 nm. The detector reduced the baseline drift associated with thermally induced refractive index aberrations, not only for TGMLC but also for mobile-phase gradient LC and flow injection analysis. The advantages of the TGMLC technique are discussed.
LC Spectrophotometry

"Determination Of Sub-nanomolar Levels Of Iron(II) And Total Dissolved Iron In Seawater By Flow Injection Analysis With Chemiluminescence Detection"
Anal. Chem. 1991 Volume 63, Issue 9 Pages 893-898
Virginia A. Elrod, Kenneth S. Johnson, and Kenneth H. Coale

Abstract: The flow injection manifold used was similar to that described previously (Sakamoto-Arnold and Johnson, ibid., 1987, 59, 1789) for Co in seawater with the addition of a column containing 8-hydroxyquinoline (I) on Fractogel. Seawater was collected in acid-washed polyoxyethylene bottles and acidified to pH 5.5. The sample was drawn through a PTFE filter (0.45 µm) and pumped (1.1 mL min-1) on to the I column for 4 min. The injection valve was switched to the 'elute' position and the Fe was eluted from the column with 75 mM HCl (1.1 mL min-1) for 1 min. The eluate stream merged with the 1 mM brilliant sulfoflavin stream (pH 8.3; 2.3 mL min-1) and then with the 2% H2O2 straem (2.3 mL min-1) before entering the flow cell. The flow cell comprised a clear PVC tube (50-cm coil) in a grey PVC housing maintained at -20°C. Light generated by the chemiluminescent reaction was detected by a photomultiplier tube connected to a photometer and a computer. Other metals did not interfere at concentration. expected in seawater. Detector response was rectilinear from 1 to 1000 nM Fe(II). The detection limit was 0.45 nM Fe(II). Calibration graphs were rectilinear at 2.5 nM Fe(II) only if peak areas were measured. Results agreed well with the certified values for reference materials.
Iron(2+) Iron Sea Chemiluminescence

"Multi-channel Amperometric Detection System For Liquid Chromatography And Flow Injection Analysis"
Anal. Chem. 1991 Volume 63, Issue 21 Pages 2418-2423
Johan C. Hoogvliet, Johannes M. Reijn, and Wouter P. Van Bennekom

Abstract: An apparatus is described having 16 working electrodes (carbon paste) in a circle, a single auxiliary electrode (vitreous carbon) and a single reference electrode (SCE), for measurements in a flowing liquid. The potential of each working electrode is controlled and the current produced at it is measured with a computer-controlled multi-channel potentiostat. The circuitry permits the measurement of currents down to 100 pA full scale. Thus complete voltammograms can be obtained in a single run. The method was exemplified by the analysis of catecholamines separated on a C18 column. Calibration graphs were rectilinear for 10^-5 to 10^-9 M epinephrine, with a detection limit of 0.12 pg injected. In another application, glutathione was detected in a flow injection analysis system, with a four-electrode array of different electrode materials. Valuable diagnostic information was obtained from the differing responses of the electrodes.
Amperometry LC Electrode

"Detection Of Anionic Polymers By Post-column Ligand Exchange With Fluorescent Cerous Ions Via A Cation-exchange Membrane"
Anal. Chem. 1991 Volume 63, Issue 24 Pages 2888-2891
Per Olof G. Edlund and Sven P. Jacobsson

Abstract: Sulfated polysaccharides, including heparin and carrageenans, were determined by the formation of fluorescent complexes with Ce3+. The reaction system incorporated a strong cation-exchange tubular membrane reactor (SciTech, Umea, Sweden). In one mode, Ce2(SO4)3 was added to the carrier solution flowing in the internal channel, and 50 mM H2SO4 flowed in the external channel; the anionic polymers were equilibrated initially with aqueous Ce(SO4)2 of the same concentration. as the carrier, and unreacted Ce3+ was removed by the H2SO4. In the other mode, the carrier was 50 mM ammonium acetate pumped through the reactor, and Ce3+ was introduced from 2 to 4 mM Ce2(SO4)3 in 50 mM H2SO4 flowing in the external channel. The fluorescence of the products was measured at 350 nm (excitation at 250 nm). Either mode could be used in flow injection analysis; the second mode was used in conjunction with size-exclusion LC on a column (30 cm x 1 cm) of Superdex (13 µm) in which the carrier also constituted the mobile phase. Samples could be desalted on a Biosil guard column (8 cm x 7.8 mm; 5 µm particles) for flow injection analysis. Response to anionic polymers was high and that to low-mol.-wt. acids was small or absent; there was a small negative response to oxalic acid. The detection limit in flow injection analysis was 1 pmol with 50 mM ammonium acetate and 0.1 pmol with water as carrier for heparin, and response was rectilinear over three decades of concentration.
Polysaccharides, sulfates Heparin LC Fluorescence

"Determination Of Chromium(III) And Chromium(VI) In Water Using Flow Injection Online Preconcentration With Selective Absorption On Activated Alumina And Flame Atomic Absorption Spectrometric Detection"
Anal. Chem. 1992 Volume 64, Issue 24 Pages 3101-3108
Michael Sperling, Shukun Xu, and Bernhard Welz

Abstract: A conically shaped micro-column (Perkin-Elmer, 50 µL) was packed with acid-activated aluminum oxide 90 (Merck, 56 to 170 µm fraction). Sequential sorption was carried out using Clark - Lubs buffer of pH 7 for Cr(III) and pH 2 for Cr(VI). The species were then eluted directly from the column to the nebulizer - burner system (with the impact bead and flow spoiler removed) using 1 M HNO3 and 0.5 M ammonia for Cr(III) and Cr(VI), respectively. Retention efficiency was >80% for Cr(III) and >90% for Cr(VI) giving a sensitivity enhancement of 25 for a 3 mL sample, and corresponding detection limits were 1.0 and 0.8 µg l-1; the calibration graph for both species was rectilinear from 10 to 200 µg l-1. Recovery from natural water samples (kept at pH 4) was 90 to 106%. The effects of diverse ions are reported and no serious interference occurred from levels normally found in natural waters. A comparison of published methods for the selective determination of Cr(III) and/or Cr(VI) by online separation techniques is also presented.
Chromium(III) Chromium(VI) Environmental Spectrophotometry

"Automated Analysis Of Radionuclides In Nuclear Waste: Rapid Determination Of Strontium-90 By Sequential Injection Analysis"
Anal. Chem. 1996 Volume 68, Issue 2 Pages 333-340
Jay W. Grate, Robert Strebin, Jiri Janata, Oleg Egorov, and Jaromir Ruzicka

Abstract: A 10 mL PTFE holding coil (HC; 20 cm) located prior to a multipoint valve (MPV) and a 50-100 µm Sr-Spec column (10 cm x 2.1 mm i.d.) was filled with water from a carrier stream. Portions (6 ml) of 8 M HNO3 reagent were subsequently drawn into the HC via the MPV and the Sr-Spec column was conditioned with 1 mL 8 M HNO3 drawn from the HC via the MPV. A 100 µL portions of strontium-90/yttrium-90, strontium-85 (yield tracer) and caesium-137 in 8 M HNO3 (preparation described) was drawn into the HC and the 'stack' of zones created in the HC was drawn through (0.5 ml/min) the column. Yttrium-90, caesium-137 and other radionuclides (present in waste samples) were displaced with 6 mL 8 M HNO3 and strontium-90 and strontium-85 subsequently displaced with 7.5 mL water. Eluates and liquid scintillation cocktail (1:2) were fed via a T-piece and a mixing coil to a liquid scintillation counter. Calibration graphs were linear up to ~25000 strontium-90 disintegrations/min. Results for aged waste samples (preparation described) were in excellent agreement with conventional analysis (procedures described).
Strontium-90 Waste Scintillation counter

"Selective And Rapid Ion-chromatographic Determinations Of Alkaline-earth Metals And Applications To The Analysis Of Barite"
Fresenius J. Anal. Chem. 1989 Volume 335, Issue 7 Pages 687-691
Daren Yan, Jingan Zhang and Georg Schwedt

Abstract: Alkaline-earth metals, Pb and Cd were separated on a column (20 cm x 4 mm) of Nucleosil SA (10 µm) with 20 mM oxalic acid - 10 mM citric acid - 2 or 3 mM ethylenediamine, adjusted to pH 3.4, as mobile phase (1 mL min-1). A solution containing 1 mM 4-(2-pyridylazo)resorcinol, 0.5 mM ZnEDTA and 2 M NH3 (pH 11) was used for post-column derivatization (flow rate 0.33 mL min-1), with absorbance measurement at 495 nm and quantitation based on peak areas. Complete separation of the above metals, Cu, Zn, Fe and Mn required a mobile phase (0.9 mL min-1) of 2 mM oxalic acid - 3 mM ethylenediamine - 0.02% of NaCl (pH 2.8). To determine alkaline-earth metals in barite, 0.1 g of sample was fused with 5 g of Na2CO3 - K2CO3 (4:1) at 700°C for 30 min, the cooled melt was leached with hot water, and the ppt. was filtered off and dissolved in HCl. The resulting solution was diluted and filtered before analysis of a 0.1 mL portion (pH ~1.5). Detection limits ranged from 25 to 100 µg L-1 and recoveries were quantitative. At mg L-1 levels, coefficient of variation ranged from 0.7 to 1.6%.
Metals, alkaline earth Barite HPIC Spectrophotometry

"Fast Lipoprotein Chromatography (FLPC): Novel Approach To The Analysis Of Plasma Lipoprotein Fractions"
Fresenius J. Anal. Chem. 1990 Volume 337, Issue 1 Pages 126-127
Hans-Wolfgang Schultis, Hans v. Baeyer, Heidemarie Neitzel, Eberhard Riedel, R&uuml;diger Siekmeier, Winfried M&auml;rz, Hubert Scharnagl and Werner Gro&szlig;

Abstract: Plasma (20 µL) was analyzed by gel-permeation chromatography on a 30-cm Superose 6 column with 0.1 M Na2HPO4 - 0.2 M NaCl (pH 7.4) as mobile phase (0.3 mL min-1), post-column derivatization with CHOD-PAP cholesterol reagent (Boehringer Mannheim) and detection at 500 nm. The response was rectilinear for 80 µL of hypercholesterolaemic plasma, and the coefficient of variation (n = 13) for very-low-density-, low-density- and high-density-lipoprotein cholesterol were 5.8, 2.0 and 1.9%, respectively. Results were more reproducible than those by conventional methods, and only a small amount of sample, with no pre-treatment, was required.
Cholesterol Blood Plasma GPC Spectrophotometry

"Selective Determination Of Triton-type Non-ionic Surfactants In Different Samples By Online Clean-up And FIA"
Fresenius J. Anal. Chem. 1990 Volume 337, Issue 4 Pages 389-392
M. E. Le&oacute;n-Gonzalez, M. J. Santos-Delgado and L. M. Polo-D&iacute;ez

Abstract: An automated flow injection analysis system with spectrophotometric detection (diagram given) is presented. The Triton sample is injected into a KNO3 - KOH - 2% ethanol carrier solution; for samples containing a large excess of ionic and amphoteric surfactants, these are retained by passing the sample through a column (1.5 cm x 1.5 mm) of Amberlite IRA-904 or IR-120 ion-exchange resin, before injection into the carrier solution An adduct of surfactant K+ (in the carrier solution) with picrate solution is formed and the resulting adduct is extracted into 1,2-dichloroethane. The non-ionic surfactants (CX-100, X-405 and WR-1339) are determined by flow injection analysis and are detected at 380 nm. Beer's law was obeyed from 0.02 to 1.2 mg l-1. The coefficient of variation (n = 10) was 0.3% at the 0.5 mg L-1 level. The method was applied to detergents, contact lens products, cosmetic remover and process water from tanneries.
Surfactants, non ionic Ion exchange

"Flow Injection Ion-exchange Preconcentration For The Determination Of Iron(II) With Chemiluminescence Detection"
Fresenius J. Anal. Chem. 1990 Volume 337, Issue 7 Pages 848-851
Abdulrahman A. Alwarthan, Khalil A. J. Habib and Alan Townshend

Abstract: Solutions of 10 µM-luminol and 10 µM-H2O2, each in 0.1 M carbonate buffer, were continuously pumped, each at 2 mL min-1, through the manifold of the flow injection system; the sample (3 ml; adjusted with 0.1 M phosphate buffer to pH 6.0) was pumped at 1.5 mL min-1 through a chelating column (2 cm x 2.5 mm i.d.) containing 8-hydroxyquinoline-5-sulfonic acid immobilized by azo-coupling on controlled-pore glass (pore diameter 22.6 nm; 80 to 120 mesh). The sample flow was then replaced by water to wash the column for 3 min. For elution of Fe, 52 µL of 0.15 M HCl was injected via the injection valve into the column, and the eluate was mixed with the reagent stream before measurement of the emitted chemiluminescence. A log - log calibration graph was rectilinear for Fe(II) pre-concentrated from triple 52 µL injections of Fe(II) solution (10 to 70 ng mL-1), and the detection limit was ~2 pg mL-1. Of the foreign ions tested, Mo(VI), VV, Ti(IV) and AgI increased and Cu(II) slightly decreased the chemiluminescence signal; Co did not interfere. One analysis took 5 min.
Iron(2+) Chemiluminescence

"Heterogeneous Equilibrium Between Solution And Slightly Soluble Compound In Flow Injection Analysis: Platinum(IV) Determination"
Fresenius J. Anal. Chem. 1991 Volume 340, Issue 1 Pages 14-18
Liliana Ilcheva Contact Information and Anastas Dakashev

Abstract: A new principle of flow injection analysis is proposed based on a change in equilibrium between solution and a slightly soluble compound as the sample passes through a column containing the slightly soluble compound (details given). A solution containing H2PtCl6 in 0.1 M HCl carrier solution was applied at 1.5 mL min-1 to a column containing Tl2PtCl6 on a porous glass support and detection with use of the current generated at a Pt electrode by the oxidation of Th(I) to Th(II); Pt is calculated from a given equation. The procedure was applied in the determination of Pt(IV) in spent catalyst on aluminum oxide supports.
Platinum(IV) Electrode

"Determination Of Polycyclic Aromatic Hydrocarbons In Diesel Soot By High Performance Liquid Chromatography"
Fresenius J. Anal. Chem. 1991 Volume 340, Issue 1 Pages 27-30
H.-J. G&ouml;tze Contact Information, J. Schneider and H.-G. Herzog

Abstract: Soot particles from exhaust fumes are collected by blowing exhaust gases for 2 min through an Al collection apparatus containing a borosilicate - glass-fiber extraction thimble. The sample is extracted with CHCl2 for 2 h in a Soxtec extractor, the extract is cleaned up on a SiO2 column (20 cm x 11 mm), eluted with CHCl2 and the eluate was treated with Al2O3 and evaporated to dryness. The residue is placed on top of an alumina column and PAHs are separated by elution with benzene, CHCl3 - 1% ethanol and methanol. These fractions were further analyzed by reversed-phase HPLC on a column (25 cm x 1 mm) of Nucleosil RP 18 (5 µm) with a mobile phase (30 µL min-1) of methanol - THF - water (49:21:30) and detection at 254 nm for the benzene fraction and fluorescence detection at 370 nm (excitation at 289 nm) for the CHCl3 fraction after post-column derivatization. The calibration graph was rectilinear over three orders of magnitude and the detection limit was 0.05 pg to 0.3 ng.
Hydrocarbons, aromatic, polycyclic Diesel Soot HPLC Fluorescence Sample preparation

"Micro-analytical Concept For Multicomponent Analysis Of Airborne Particulate Matter"
Fresenius J. Anal. Chem. 1991 Volume 340, Issue 9 Pages 525-533
Wolfgang Frenzel

Abstract: Atmospheric particulate matter, collected on membrane filters, was subjected to aqueous extraction (200 µL of ethanol, 2.8 mL of H2O) in an ultrasonic bath. A 50 µL portion of the extract was analyzed for NH4+ by a flow injection procedure with photometric detection (cf. Schulze et al., Anal. Chim. Acta., 1988, 214, 121), and for Cl-, NO3- and SO42- simultaneously by ion chromatography on a column (15 cm x 4.1 mm) of PRP-X 100 with 2 mM KH phthalate (pH 6.8) as mobile phase and conductivity detection. The remainder of the extract was subjected to concentrated HNO3 - HF - H2O2 digestion in a closed microwave system, before flame AAS and graphite furnace AAS determination of ten and six elements, respectively. A flow-chart of the microchemical procedure is presented. Results obtained from the analyzes of standard reference materials, an inter-laboratory comparison, and from alternative methods of accuracy control indicated that most components were determined with reasonable or good precision and accuracy by the described procedure.
Ammonium Particulates Spectrophotometry Sample preparation Sample preparation

"Development Of Analytical Methods For The Determination Of Ions And Acidity In Individual Raindrops"
Fresenius J. Anal. Chem. 1991 Volume 340, Issue 9 Pages 548-552
K. B&auml;chmann, I. Haag, U. Sprenger, K.-H. Steeg, K. Steigerwald, B. Bastian and A. R&ouml;der

Abstract: Raindrops are frozen in liquid N and separated by size fractionation with use of mesh sieves. Several analytical procedures are also described for the determination of ions at ultratrace levels and with volume 1 µL; free and total acidity of the drops are determined by the reaction with suitable acid/base indicators in a flow-injected system with gradient mixing and UV - visible spectrophotometric detection. Alkaline- and alkaline-earth-metals are determined on microbore cation-exchange columns of ION-210 metals and Fast Cation 1 with Ce as mobile phase. Formate, Cl-, NO3- and SO42- anions are separated on a column of PRP X-100 with 3 mM Na2CO3 buffer - 6% acetonitrile - 0.17 mM p-cyanophenol as mobile phase and with conductivity detection. Acetate, formate, pyruvate and methane sulfonate are separated on a column of HPIC AS5A with Na2B4O7 as mobile phase. Iron, Pb and Mn are determined from size fractions by graphite-furnace AAS. Detection limits are given.
Acidity Rain Spectrophotometry Spectrophotometry

"Determination Of Sulfate And Phosphate By Flow Injection Analysis Using A Barium Chloranilate Packed Column"
Fresenius J. Anal. Chem. 1993 Volume 347, Issue 10-11 Pages 409-412
Minori Kamaya, Kunio Nagashima and Eizen Ishii

Abstract: For the determination of sulfate, sample solution was passed through an Amberlite CG-120 cation exchange resin column (10 cm x 8 mm i.d.) to remove the interfering cations, the eluate was evaporated to dryness, reconstituted with aqueous 80% 2-propanol and loaded on to a column (details given) packed with barium chloranilate. The carrier solution was aqueous 60% 2-propanol (1 ml/min) and detection was at 310 nm. Phosphate was determined after treating sample solution with 0.1 M ammonium molybdate in the presence of HCl; the complex formed was extracted into isobutyl methyl ketone and the extract washed with HCl and aqueous NH3 before evaporation to dryness. The residue was reconstituted with aqueous 50% 2-propanol and the solution was injected on to a column of barium chloranilate with elution as above and detection at 325 nm. Calibration graphs were linear from 2.5-1000 mM and 8-40 µM for sulfate and phosphate, respectively; the RSD (n = 6) were 1.3%. Results are discussed.
Sulfate Phosphate

"Preconcentration Of Inorganic Selenium Species (selenium(IV) And Selenium(VI)) In An Alumina Filled Micocolumn And Online Determination By Hydride Generation Atomic Absorption Spectrometry"
Fresenius J. Anal. Chem. 1994 Volume 350, Issue 12 Pages 667-670
A. Larraya, M. G. Cobo-Fern&aacute;ndez, M. A. Palacios and C. C&aacute;mara

Abstract: A flow injection system has been developed consisting of on-line pre-concentration of selenium species in a microcolumn filled with activated alumina, reduction of Se(VI) to Se(IV) and determination by HG-AAS. When 0.01 mol/L HNO3 is used both as carrier and activation reagent for the alumina microcolumn, up to 150 ng of Se(IV) and Se(VI) can be pre-concentrated and quantitatively eluted by 500 L of 2 mol/L NH3. The pre-concentration factor is 50 when 25 mL of sample is used. The detection limit is about 6 ng/L, the precision is 5% for low concentrations such as 150 ng/L and 3% at high concentrations such as 120 ng/mL. The proposed method is suitable for natural water samples and inorganic Se speciation can be performed by determining Se(IV) and total selenium [Se(VI) is evaluated from the difference].
Selenium(IV) Selenium(VI) Spectrophotometry

"Flow Procedure For Ion-exchange Preconcentration And Online Spectrophotometric Determination Of Iron(III) As Its Thiocyanate Complex"
Fresenius J. Anal. Chem. 1995 Volume 352, Issue 6 Pages 601-602
Ala'ddin M. Almuaibed and Alan Townshend

Abstract: Sample was pumped via a 3-way valve at 1.5 ml/min for 4 min through a Dowex-50 W cation exchange column (25 cm x 0.25 mm i.d.). The value was switched and 1.2 M H2SO4 containing 0.082 M KSCN was pumped through the system to elute Fe(III) retained on the column. The resulting stream was monitored at 465 nm. The calibration graph was linear for 0.01-0.2 µg/ml of Fe(III) with a detection limit of 6 ng/ml and RSD (n = 4) of 3% at 0.08 µg/ml of Fe(III). The effect of foreign ions are discussed.
Iron(III) Ion exchange Spectrophotometry

"Development Of An Automated Flow Injection Chemiluminescence Immunoassay For Human Immunoglobulin G"
Fresenius J. Anal. Chem. 1995 Volume 352, Issue 7-8 Pages 793-796
Andrea Hacker, Martin Hinterleitner, Curt Shellum and Gerald G&uuml;bitz

Abstract: An immunoreactor flow cell was constructed comprising a transparent PTFE tube (2 cm x 1.5 mm i.d.) packed with anti-human IgG immobilized on Affi-prep 10 support (details given). The immunoreactor was equilibrated with assay buffer of 0.01 mM sodium phosphate buffer/0.14 M NaCl/0.05% NaN3 of pH 7 at 0.3 ml/min, serum sample was injected at 0.03 ml/min and, after 1 min, the buffer was changed to the elution buffer of 32 mM 85% phosphoric acid of pH 1.8 (0.3 ml/min) and H2O2/NaOH solution was injected. Detection was by chemiluminescence. The detection limit was 7 fmol/injection of IgG in serum with intra-assay RSD (n = 7) of 1-3% and inter-assay RSD (n = 21) of 1.4%. Recoveries of 15.6 and 31.2 µM-IgG from serum were 102.2 and 103.4%, respectively.
Immunoglobulin G Serum Human Chemiluminescence Immunoassay

"Ion Exchange Micro Columns For Online Preconcentration Of Heavy Metals. 2. Online Break-through Test For Zinc, Cadmium And Lead"
Fresenius J. Anal. Chem. 1995 Volume 353, Issue 2 Pages 119-122
O. Elsholz, and G. Schulze

Abstract: An on-line break-through test for zinc, cadmium and lead has been carried out by means of a flow-through cell and computerized potentiometric stripping analysis. This test has been applied to seventeen ion-exchange materials and enabled within a short time a predecision about the suitability of a resin for a special precon-centration problem. For the determination of the three trace elements in drinking water five ion exchangers are found to be appropriate without restriction and eight resins with some restrictions (not suitable for all three elements, weak matrix influences).
Cadmium Lead Zinc Ion exchange

"Anionic Cartridge Preconcentrators For Inorganic Arsenic, Monomethylarsonate And Dimethylarsinate Determination By Online HPLC-HG-AAS"
Fresenius J. Anal. Chem. 1997 Volume 357, Issue 7 Pages 844-849
M. G&oacute;mez, C. C&aacute;mara, M. A. Palacios, A. L&oacute;pez-Gonz&aacute;lvez

Abstract: Preconcentration anionic cartridges in combination with hyphenated FI-HG-AAS and HPLC-HG-AAS have been evaluated for the pre-concentration and quantification of total toxic arsenic and of inorganic arsenic, monomethylarsonate and dimethylarsinate species, respectively. Optimum retention and elution parameters of the species on the anionic cartridges are evaluated and the quality parameters of the analysis are reported. The detection limits for the arsenic species under study range from 0.1 µg L-1 to 0.6 µg L-1. The proposed method was successfully applied to the determination of arsenic species in spiked fresh water.
Arsenic, inorganic monomethylarsonic acid Dimethylarsinic acid HPLC Ion exchange Spectrophotometry

"Semi-automatic Determination Of Tin In Marine Materials By Continuous-flow Hydride-generation Inductively Coupled Plasma Atomic-emission Spectrometry"
Fresenius J. Anal. Chem. 1997 Volume 357, Issue 7 Pages 822-826
Yong-Lai Feng, H. Narasaki, Hong-Yuan Chen, Li-Ching Tian

Abstract: Sample (1.25 g) was equilibrated overnight with 15 mL 68% HNO3 and 2 mL 70% HClO4, then digested by heating with 0.5 mL concentrated H2SO4. The resulting solution was adjusted to pH 3.5 with 4 M NaOH and passed through a DIAION SA 10A anion-exchange resin column (15 cm x 8 mm i.d.; Mitsubishi Kasei Corp., Tokyo, Japan). The eluate was mixed with 3.5 mL 3 M H2SO4 and 2.5 mL 10% L-cysteine hydrochloride monohydrate, diluted to 25 mL and then analyzed for Sn by continuous-flow hydride-generation ICP-AES at 189.93 nm (operating conditions given). The detection limit was 0.4 ng/mL Sn and the RSD (n = 10) was 0.5%. The effects of varying the H2SO4, NaBH4 (hydride-generating reagent) and NaOH concentrations, Ar (carrier gas) and NaBH4 flow rates and the ratio of flow rates of sample solution and NaBH4 were investigated (results presented). The effects of interferents were also investigated, along with seven methods for masking interference (results tabulated). The method was applied to an environmental (marine) CRM. The result agreed with the certified value and the RSD (n = 6) was 0.95%.
Tin Environmental Marine Ion exchange Sample preparation Spectrophotometry

"Liposome-based Flow Injection Enzyme-immunoassay For Theophylline"
Microchim. Acta 1990 Volume 100, Issue 3-4 Pages 187-195
Tai -Guang Wu and Richard A. Durst

Abstract: A peristaltic pump was used to supply, in 0.1 M Tris buffer (pH 7.2) as carrier, a standard solution of theophylline (I) or plasma sample, in the same buffer, to a column (17.8 cm x 2.5 mm) of glass beads coupled to monoclonal anti-theophylline antibodies. The injector (Rheodyne type 7010) then delivered a solution of liposomes that encapsulated horse-radish peroxidase and had been sensitized with 4-(1,3-dimethylxanthin-8-yl)butyric acid (II). Competition between I and II for the antibodies occured, and unbound liposomes were eluted for post-column reaction with H2O2 and 4-fluoriphenol. This reaction caused release of F-, which was determined with an Orion model 69-09 ion-selective electrode. The column was then washed with glycine - HCl solution to dissociate the antigen - antibody complex and reactivate the column. Calibration graphs are presented for two liposome compositions (10 and 20 miu mL-1 of enzyme activity). I can be detected over the concentration. range 0.2 to 4000 ng mL-1, i.e., a detection limit of 100 fmol in a 0.1 mL sample. For an activity of 10 miu mL-1, the coefficient of variation (n = 6) was 4.6% at the level of 4.3 ng mL-1. The assay takes ~10 min.
Theophylline Blood Plasma Immunoassay Electrode

"HPLC Post-column Derivatization Of Aromatic Amines Using N-methyl-9-chloroacridinium Triflate"
Microchim. Acta 1990 Volume 102, Issue 4-6 Pages 221-232
Myungsoo Kim and James T. Stewart

Abstract: Benzocaine (I) and butesin (II) in mobile phase were separated by HPLC on a column (25 cm x 4.6 mm) of ASI ODS (5 µm) with aqueous 80% methanol as mobile phase (1 mL min-1). Hydralazine (III), isoniazid (IV) and procainamide (V) in mobile phase were separated by HPLC on a column (10 cm x 4.6 mm) of Brownlee RP-8 (5 µm) with 100% methanol - aqueous phosphate buffer of pH 3 (1:1) as mobile phase (1 mL min-1). The column eluates were mixed with N-methyl-9-chloroacridinium triflate in acetonitrile (details given) and detected at 460 nm. Calibration graphs for I and II were rectilinear from 25 to 500 µM; coefficient of variation ranged from 1 to 6%. The limit of detection for I and II was 100 ng mL-1. Recoveries of III, IV and V were >97%, with coefficient of variation of 1.6, 0.5 and 1.4%, respectively.
Amines, aromatic HPLC

"Application Of An Online Preconcentration System In Simultaneous ICP-AES"
Microchim. Acta 1992 Volume 106, Issue 3-6 Pages 191-201
Peter Schramel, Li -Qiang Xu, G&uuml;nter Knapp and Markus Michaelis

Abstract: A PC-controlled online pre-concentration system (TRACECON) was connected to a JY-70 Plus simultaneous inductively coupled plasma (ICP) spectrometer to pre-concentrate online seven trace elements (Cu, Fe, Zn, Cr, Ni, Mn, V) in biological and environmental samples. EDTrA-cellulose was used as column material. The elemental concentrations were determined by simultaneous ICP-AES. The effect of pH of the sample solution on the enrichment was studied. It was found that the recoveries of chromium and iron depend strongly on the pH of the sample solution. All the elements mentioned were recovered quantitatively at pH 4.0. The flow rates of sample solution and element solution were optimized. The enrichment factors for seven elements at 5 mL loading volume range from 3.9 for Cu to 7.9 for Zn. The detection limits of all seven elements were improved. The accuracy of the method was tested by the analysis of a number of CRMs of NIST, BCR and NIES. Most results are in good agreement with the certified values.
Copper Iron Zinc Chromium Nickel Manganese Vanadium Biological Environmental Spectrophotometry

"Acridinium Ester Chemiluminescence: PH-dependent Hydrolysis Of Reagents And Flow Injection Analysis Of Hydrogen Peroxide And Glutamate"
Microchim. Acta 1992 Volume 108, Issue 3-6 Pages 205-219
Maureen Stuever Kaltenbach, and Mark A. Arnold

Abstract: A flow injection system is described for the determination of H2O2 based on the chemiluminescent reaction with 10-methyl-9-phenoxycarbonylacridinium (I). The carrier stream is pumped at 4 mL min-1 and consists of a standard H2O2 solution in boric acid buffer solution of pH 9; the concentration. of the standard solution cover the range 0.1 µM to 1 mM H2O2. I reagent (20 µL) is injected into the carrier stream and the solution are mixed by passage through a coiled incubation tube. The chemiluminescence reaction is initiated by adding a base just before the sample passes in front of a photomultiplier tube. The detection limit is 0.25 µM. By coupling this system to an enzyme column it is possible to determine glutamate, the H2O2 formed as glutamate passes through a reaction column of L-glutamate oxidase being determined by the above procedure. The detection limit is 0.5 µM with a throughput of 300 samples h-1. An automated anal. system is described for the measurement of hydrogen peroxide based on a chemiluminescence reaction with Ph 10-methylacridinium-9-carboxylate (PMAC). A reversed FIA experimental arrangement is used to establish the operating conditions for the measurement of submicromolar levels of hydrogen peroxide. The carrier stream consists of hydrogen peroxide standards prepared in a pH 9.0, boric acid buffer and the flow rate for this carrier/sample stream is 4 mL/min. Twenty microliters of a 10 mM PMAC solution, prepared in a pH 3 phosphate buffer, are injected into the carrier/sample stream. Hydrogen peroxide mixes with the PMAC reagent in an incubation coil that is constructed by wrapping 107 cm of polyethylene tubing around a 1 cm o.d. plastic rod. The chemiluminescence reaction is then initiated by adding a base just before the sample passes in the front of a photomultiplier tube detector. The calculated limit of detection (S/N = 3) for hydrogen peroxide is 0.25 µM. In addition, the pH dependent hydrolysis of the PMAC reagent is characterized by an HPLC method which has been specifically developed for the separation and detection of the hydrolysis products of PMAC. Results indicate that a pH of 3.0 is required for long term stability of the PMAC reagent. Finally, this system has been successfully extended to the measurement of glutamate by coupling a bioreactor column of glutamate oxidase with the hydrogen peroxide detection scheme. A detection limit (S/N = 3) of 0.5 µM has been established for glutamate with a throughput of 200 samples per h.
Hydrogen peroxide Glutamate Chemiluminescence

"Flow Injection Catalytic Spectrophotometric Method For The Determination Of Permanganate"
Microchem. J. 1995 Volume 52, Issue 1 Pages 77-80
Almuaibed A. M. and Townshend A.

Abstract: Sample (75 µL) was injected into a stream (1.5 ml/min) of 0.6 M HClO4 and passed through a column (3 cm x 0.25 mm i.d.) of cation exchanger (Dowex 50 W resin, 100-200 mesh). The flow then merged with streams (0.75 ml/min) of 1.4 mM KIO4 and 40 µM-tris-(1,10-phenanthroline)-Fe(II) complex, before passage through a reaction coil (70 cm) and measurement of absorbance at 505 nm. Ru(III) interference was removed by the cation-exchanger. The calibration graph was linear from 0.05-0.4 µg/ml of permanganate and the detection limit was 2.5 ng. The RSD (n = 10) at 0.3 µg/ml was 2%. Sample throughput was 110/h.
Permanganate Spectrophotometry

"Determination Of Acetylcholine And Choline By Flow Injection With Immobilized Enzymes And Fluorimetric Or Luminometric Detection"
Anal. Biochem. 1989 Volume 176, Issue 2 Pages 221-227
Jan R&iacute;cn&yacute;, Jil&iacute; Coupek and Stanislav Tucek

Abstract: Acetylcholine and choline were determined in solution and tissue extracts by a continuous-flow system with a sequence of enzyme reactors containing immobilized acetylcholinesterase, choline oxidase and peroxidase. Additional reactors with immobilized choline oxidase and catalase were used to remove choline and choline-generated H2O2 from samples when acetylcholine was being determined. Acetylcholinesterase, choline oxidase and catalase were immobilized on Separon HEMA E and peroxidase was immobilized on Separon HEMA (for fluorimetric detection) or on a coiled glass capillary or on controlled-pore glass beads (for luminometric detection). Detection was by measuring fluorescence generated from the reaction of H2O2 with 3-(4-hydroxyphenyl)propionic acid in presence of peroxidase, or measuring luminescence generated from the reaction of H2O2 with luminol in presence of peroxidase. Calibration graphs were rectilinear up to 100 pmol of acetylcholine with fluorescence detection. Detection limits were 10 or 25 pmol of acetylcholine with the coiled-capillary peroxidase or controlled-pore-glass peroxidase columns, respectively, with luminometric detection, and 0.2 pmol with fluorimetric detection.
Acetylcholine Choline Biological tissue Luminescence Fluorescence

"Flow Injection Binding Assays: A Way To Increase The Speed In Binding Analyses"
Anal. Biochem. 1989 Volume 181, Issue 2 Pages 379-382
Bo Mattiasson, Per Berd&eacute;n and Torbj&ouml;rn G. I. Ling

Abstract: A flow injection binding assay for glucosides and mannosides is described. The sample was mixed with enzyme label (horseradish peroxidase) and passed through a column of immobilized concanavalin A. Bound activity was measured by passing substrate (to peroxidase) and chromogenic reagent through the column and monitoring the effluent spectrophotometrically. To speed up the assay, the sample was applied in pulses and the substrate was included in the column regeneration buffer. Calibration graphs for glucosides and mannosides were rectilinear for 0.02 to 2 mM.
Carbohydrates Glycoproteins Glycosides Mannosides Spectrophotometry

"Determination Of Thiobarbituric Acid-reactive Substances In Oxidized Lipids By High Performance Liquid Chromatography With A Post-column Reaction System"
Anal. Biochem. 1989 Volume 182, Issue 1 Pages 116-120
Kazuaki Yoden* and Toshihiro Iio

Abstract: Free malonaldehyde (I) and other thiobarbituric acid-reactive substances were determined in oxidized lipids (prep. described) by HPLC on a column (15 cm x 6 mm) of Inertsil ODS-2 (5 µm) with linear gradient elution (0.7 mL min-1) from aqueous 50 to 100% methanol over 30 min, and held at 100% methanol for 15 min. The eluate was mixed (0.7 mL min-1) with 0.5% 2-thiobarbituric acid in 0.05 M HCl in a reaction coil (20 m x 0.4 mm) at 55°C and the resulting red pigment was determined fluorimetrically at 553 nm (excitation at 515 nm). The calibration graph was rectilinear up to 4 nM-I and the detection limit was 0.5 nM. The procedure was applied in the analysis of thermally oxidized methyl linoleate, the degradation products of methyl linoleate hydroperoxides and the oxidation products of rat liver microsomes.
Thiobarbituric acid Liver HPLC Fluorescence

"Determination Of Inorganic Phosphate By Flow Injection Method With Immobilized Enzymes And Chemiluminescence Detection"
Anal. Biochem. 1989 Volume 182, Issue 2 Pages 366-370
Hideki Kawasaki, Katsumi Sato, Jyunko Ogawa, Yukio Hasegawa and Hidetaka Yuki

Abstract: Inorganic phosphate (I) was determined by flow injection analysis with use of two glass columns (0.9 cm x 3 mm), one packed with purine-nucleoside phosphorylase-coated controlled-pore glass beads (AMP-500; 120 to 200 mesh), and the second packed with xanthine oxidase and urate oxidase-coated beads (preparation described). The carrier solution (1 mL min-1) was 25 µM inosine in 10 mM HEPES - NaOH buffer (pH 7.5) and the H2O2 produced was determined with use of 10 µM luminol and 0.8 µM peroxidase in 50 mM carbonate buffer (pH 10.5) and chemiluminescence detection. The calibration graph was rectilinear for 5 to 250 pmol of K2HPO4 and the detection limit was 500 fmol. The within-assay coefficient of variation was 1.03 to 9.36%. The method was applied in determination of I in DNA.
Phosphate DNA Chemiluminescence

"Determination Of Phosphatidylcholine In A Flow Injection System Using Immobilized Enzyme Reactors"
Anal. Biochem. 1990 Volume 187, Issue 2 Pages 240-245
Mohammed Masoom, Rita Roberti and Luciano Binaglia

Abstract: Two alternative procedures are described for the quantitative determination of phosphatidylcholine in a flow injection system utilizing immobilized enzymes. Phospholipase C from Bacillus cereus and phospholipase D from cabbage were covalently bound to the surface of controlled-pore glass beads and the enzyme-derivatized beads were packed in small columns. In the first procedure, the phospholipase C column was connected with a second column containing coimmobilized alkaline phosphatase and choline oxidase. In the alternative procedure, the column packed with immobilized phospholipase D was connected with a column packed with immobilized choline oxidase. The hydrogen peroxide produced through the action of choline oxidase in both flow injection systems was detected amperometrically. Both procedures are suitable for an accurate and rapid quantitation of phosphatidylcholine. The sensitivity of the method based on phospholipase C and alkaline phosphatase is higher than that using phospholipase D. Quantitation of phosphatidylcholine at the nanomole level can be easily obtained using the first methodology. Membrane lipids were extracted from brain by the method of Folch et al. (J. Biol. Chem., 1957, 226, 497) and dissolved in CHCl3 - methanol (2:1). The solution was evaporated in vacuo and the lipid residue was dissolved in 0.1 M Tris - HCl buffer of pH 7.5 containing 0.3% of Triton X-100 and 0.4 mM ZnCl2. The suspension was injected into a stream (pH 6.5) of 30 mM CaCl2 containing 0.3% of Triton X-100 and 20 mM diethylbarbitone and passed through columns of phospholipase C immobilized on glass beads and of alkaline phosphatase and choline oxidase immobilized on glass beads before electrochemical detection with a vitreous-carbon electrode at +0.6 V. The calibration graph was rectilinear for 0.05 to 2 mM phosphatidylcholine. The sensitivity was higher than that of a flow injection method using phospholipase D.
Phosphatidylcholine Amperometry Electrochemical analysis Electrode

"Determinations Of Lactate And Lactate Dehydrogenase Activity In Serum With The Flow Injection Analysis System Involving Immobilized Enzyme Column And Chemiluminescence"
Anal. Biochem. 1991 Volume 193, Issue 1 Pages 112-117
Masayoshi Tabata, Masayuki Totani* and Takashi Murachi

Abstract: The methods for the highly sensitive flow injection analysis of lactate and lactate dehydrogenase (LDH) activity in serum using immobilized enzymes in column form and chemiluminescence detection which does not require a blank correction are described. The methods were based on the determination of chemiluminescence formed by the reaction of a luminol-ferricyanide mixture with hydrogen peroxide. This hydrogen peroxide was produced by the lactate oxidase (LOD) reaction from lactate, which was in serum or was produced by the action of LDH in serum. The action of LDH in a flow injection analysis system was performed for 2 min in an incubation coil placed parallel to the substrate-buffer line between the LOD column and the LOD/catalase column. Endogenous lactate in serum was removed by an immobilized LOD/catalase column prior to the action of LDH. The present method gave perfect linearity of the data up to 5.6 mmol/liter for lactate and 1840 IU/liter for LDH activity with satisfactory precision, reproducibility, and accurate reaction recoveries. The results from the lactate and LDH activity correlated satisfactorily with those obtained by other well-established methods. Serum was applied to a column of lactate oxidase - catalase immobilized on alkylamine glass beads. The eluate was incubated at 37°C for 2 min with phosphate buffer solution (pH 7.5) containing pyruvate and NADH. The mixture was applied to a lactate oxidase column and the eluate was subjected to chemiluminometric determination (J. Appl. Biochem., 1984, 6, 251). Lactate in serum was determined as above but the sample was applied directly on to the lactate oxidase column. The calibration graph was rectilinear for 5.6 mM lactate and the detection limit was 10 µM. For lactate dehydrogenase, the calibration graph was rectilinear for 1840 IU L-1 and the within- and day-to-day coefficient of variation were 3.0 and 3.9%, respectively. The results correlated well (r = 0.974) with those obtained on a Hitachi Model 726 discrete automatic analyzer. with use of pyruvate as substrate.
Lactate Enzyme, lactate dehydrogenase Blood Serum Chemiluminescence

"Flow Injection Analysis Of Lactose Using Covalently Immobilized β-galactosidase, Mutarotase, And Glucose Oxidase/peroxidase On A 2-fluoro-1-methylpyridinium Salt-activated Fractogel Support"
Anal. Biochem. 1991 Volume 194, Issue 1 Pages 16-24
Dyer Narinesingh, Valerie A. Stoute, Gershwin Davis and That T. Ngo

Abstract: Milk samples were analyzed for their lactose content using flow injection analysis and incorporating immobilized β-galactosidase or β-galactosidase/mutarotase and glucose oxidase/peroxidase bioreactors. These enzymes were immobilized, under mild conditions, on to a 2-fluoro-1-methylpyridinium salt-activated Fractogel support. The use of a phosphate buffer (0.15 M) was found to facilitate the rapid mutarotation of α-D-glucose and hence could obviate the need for the more expensive mutarotase. The chromogenic agents of choice for monitoring the reaction were 3-methyl-2-benzothiazolinone hydrazone and 3-dimethylaminobenzoic acid. Linearity was observed over the concentration range 16-160 µg/ml using lactose standards (r = 0.996). Between 30 and 40 milk samples/h can be analyzed. Comparisons are made with existing HPLC and alkaline methylamine methods for a range of milk matrices. The FIA method consistently gives the lowest standard deviations and coefficient of variation for the various milk matrices analyzed. Milk was incubated at 25°C for 10 min with concentrated HCl and then gravity-filtered. The filtrate was adjusted to pH 6.5 and mixed with 3-dimethylaminobenzoic acid and 3-methyl-2-benzothiazolinone hydrazone in phosphate buffer solution (pH 6.5). The mixture was subjected to flow injection analysis at 33°C on a column of β-galactosidase in series with a bioreactor of glucose oxidase - peroxidase, with detection at 590 nm. The calibration graph was rectilinear for 160 µg mL-1 of lactose and the coefficient of variation was 2.7 to 3.8% (n = 3). Between 30 and 40 samples per h can be analyzed.
Lactose Milk Spectrophotometry

"Reversed-phase Ion-pair High Performance Liquid Chromatography Method For Bovine Testicular Hyaluronidase Digests Using Post-column Derivatization With 2-cyanoacetamide And Ultra-violet Detection"
Anal. Biochem. 1991 Volume 196, Issue 1 Pages 183-191
Jeffrey A. Cramer and Leonard C. Bailey

Abstract: Bovine testicular hyaluronidase was incubated with hyaluronic acid hexasaccharide, at 37°C. After addition of the mobile phase [0.03 M tetrabutylammonium hydroxide (pH 9.0) - acetonitrile (4:1)], the mixture was subjected to HPLC on a column (15 cm x 4.1 mm) of Hamilton PRP-1 polymeric C18. The mobile phase flow rate was 0.8 mL min-1 and the eluant was mixed with 1% 2-cyanoacetamide in 0.2 M Na borate buffer (pH 9.0) for 2 min at 100°C before cooling and detection at 276 nm. The calibration graphs were rectilinear for 10 to 400 nmol of C-4 and C-6 oligomers and the coefficient of variation were 1.5 to 5.7%.
HPLC Spectrophotometry

"Determination Of Serum Cholinesterase Activity By Liquid Chromatography With Electrochemical Detection"
Anal. Biochem. 1991 Volume 196, Issue 2 Pages 377-384
R. Brent Miller and C. LeRoy Blank

Abstract: Serum was incubated at room temperature for 10 min in phosphate buffer solution (pH 7.2) containing ethylhomocholine, choline and acetylcholine. After addition of HClO4 and centrifugation, the supernatant solution was subjected to HPLC on a C18 (3 µm ODS) column (10 cm x 3.2 mm). The mobile phase (0.9 mL min-1) was Tris buffer solution (pH 7.5) containing acetic acid, tetramethylammonium chloride, Na octyl sulfate, NaN3, EDTA and acetonitrile. Post-column derivatization was effected with choline oxidase and acetylcholinesterase with electrochemical detection at 0.5 V vs. Ag - AgCl. The limit of detection was 3 pmol of choline or 0.1 µmol mL-1 h-1 of cholinesterase. The calibration graph was rectilinear for up to 269 µmol mL-1 h-1, with a coefficient of variation of 1.7%.
Enzyme, cholinesterase Blood Serum HPLC Electrochemical analysis

"Luminescent Immobilized Enzyme Test Systems For Inorganic Pyrophosphate: Assays Using Firefly Luciferase And Nicotinamide-mononucleotide Adenylyl Transferase Or Adenosine-5'-triphosphate Sulfurylase"
Anal. Biochem. 1991 Volume 197, Issue 1 Pages 266-272
Bruce A. Barshop*, David T. Adamson

Abstract: Cell culture growth medium was analyzed automatically with use of a luminescent immobilized enzyme test system (described) in which the sample was mixed with NAD - luciferin (I) or adenylophosphosulfate - I and passed through a column of immobilized NMN adenylytransferase or ATP sulfurylase, respectively, with continuous-flow luminescence detection. The limit of detection was 50 nM-pyrophosphate and the coefficient of variation was 15.3%. The method was applied to analysis of fibroblasts and lymphocytes.
Pyrophosphate Luminescence

"High Performance Liquid Chromatographic Determination Of Pyrophosphate In The Presence Of A 20,000-fold Excess Of Orthophosphate"
Anal. Biochem. 1991 Volume 199, Issue 2 Pages 279-285
Norimasa Yoza, Izumi Akazaki, Tetsuya Nakazato, Nobuyuki Ueda, Hiroki Kodama and Akira Tateda

Abstract: Mixed samples of orthophosphate (I) and pyrophosphate (II) (100 µL) were injected into the carrier stream of 0.23 M or 0.18 M KCl and 0.1% Na4EDTA (1 mL min-1) and was passed through a column (25 cm x 4 mm) of TSK-gel SAX (10 µm). The eluate was mixed with a reagent stream (0.5 mL min-1) of Mo(V) - Mo(VI) for reaction in a reaction coil (15 m x 0.5 mm) of PTFE at 140°C. The cooled mixture was analyzed at 330 to 800 nm. The presence of a 20,000-fold excess of I did not interfere seriously. The working range was from 0.3 to 500 µM I and II, with coefficient of variation of 2 to 10%.
Pyrophosphate HPLC

"Peroxidase- And Tetracyanoquinodimethane-modified Graphite Paste Electrode For The Measurement Of Glucose/lactate/glutamate Using Enzyme-packed Bed Reactor"
Anal. Biochem. 1995 Volume 224, Issue 1 Pages 428-433
Pandey P. C. and Weetall H. H.

Abstract: A flow injection analysis sensor for the measurement of glucose/lactate/glutamate is reported. The glucose oxidase/glutamate oxidase/lactate oxidase was immobilized on silanized controlled pore glass particles and packed into a Teflon column (i.d., 1.2 mm; length, 40 mm) to give a bed for glucose/lactate/glutamate. The hydrogen peroxide formed by the enzymatic reaction in the packed bed was monitored by a horseradish peroxidase- and tetracyanoquinodimethane (TCNQ)- modified graphite paste electrode at 50 mV vs Ag/AgCl. The glucose oxidase/lactate oxidase/glutamate oxidase were regenerated in the packed bed, whereas peroxidase was regenerated in the TCNQ-mediated graphite paste electrode by the oxidation of TCNQ. The oxidized TCNQ was electrochemically reduced at 50 mV vs Ag/AgCl. The cathodic current obtained by the reduction of TCNQ determined the concentration of the injected analytes in the packed bed. The system showed very rapid response. Response curves for the analysis of peroxide, glucose, lactate, and glutamate are reported.
Glucose Lactate Glutamate Sensor Electrode

"Exploitation Of The Flow Injection Approach For Analytical Procedures Based On Enzymic Amplification Reactions"
Anal. Lett. 1990 Volume 23, Issue 2 Pages 225-240
Hansen, E.H.;Arndal, A.;Norgaard, L.

Abstract: The concept of using flow injection analysis (FIA) to determine tracea of substrates by enzymatic amplification procedures is discussed. Substrate recycling is accomplished by incorporating into the FIA manifold a small column reactor with co-immobilized enzymes allowing enzymatic degradation and the subsequent detection of a suitable reaction product, which can be individually optimized. At ~60 samples h-1, initial investigations with a model system based on co-immobilized lactate oxidase (I) and lactate dehydrogenase (II) yielded an amplification factor of 40 for each substrate for determination of lactate or pyruvate in the µM range. The wt. ratio of I and II was 1:1 and chemiluminescence was used for the detection of H2O2 formed by the repeated recycling processes. Further optimization of the packed enzyme column reaction should lead to considerably improved amplifications.
Chemiluminescence

"Synthetic IgG Receptor, Avid AL: Applications In Quantitative IgG Determination And In Immunoprecipitation"
Anal. Lett. 1991 Volume 24, Issue 11 Pages 2005-2015
Narinesingh, D.;Pope, A.;Khatter, N.;Ngo, T.T.

Abstract: Flow injection analysis and low-pressure liquid affinity chromatography are combined to give a method for the determination of IgG using the affinity gel Avid AL as IgG receptor. The cartridge was conditioned with PBS binding buffer (0.01 M Na2HPO4 - 0.15 M NaCl - 0.01% NaN3, pH 7.3) at 1.5 mL min-1 and human IgG standards were injected into the buffer stream at 0.5 mL min-1. The absorbance of unbound protein in the effluent was monitored at 280 nm. When the value returned to baseline, the column was eluted with 0.1 M acetic acid at 2.9 mL min-1 and the absorbance was monitored as before. Between each sample injection the column was conditioned with regeneration and binding buffer. At an optimized sample loop size of 150 µL, the calibration graphs were rectilinear up to 2.5 mg mL-1 (375 µg applied to column), the recovery was 99 to 101% and the coefficient of variation were 4.1 and 1.9% for 0.36 and 1.32 mg mL-1 of IgG, respectively (n = 12). The determination of IgG in human serum had a throughput rate of 10 min and a detection limit of 0.06 mg mL-1. The quantitative immuno-precipitation of soluble antibodies using Avid AL is also described.
Immunoglobulin G Serum Human LC

"Combining Low-pressure Liquid Affinity Chromatography And Flow Injection Analysis For The Quantitation Of Immunoglobulins"
Anal. Lett. 1991 Volume 24, Issue 12 Pages 2147-2155
Narinesingh, D.;Ngo, T.T.

Abstract: Sample (100 µL) was injected into a phosphate-buffered saline binding buffer stream (0.7 mL min-1) and passed through a Protein A affinity column (prepared as described by Ngo, Biotechnol., 1986, 4, 134). The absorbance of the effluent was monitored at 280 nm. When the absorbance peak returned to baseline any bound immunoglobulin on the column was eluted with 0.1 M sodium acetate of pH 3 (1.5 mL min-1) and the eluate was monitored at 280 nm. Calibration graphs were rectilinear up to at least 4 and 10 mg mL-1 of IgG in human and bovine standards, respectively. Recoveries were 95.8 to 100.6%.
Immunoglobulins LC

"Enzymic Flow Injection Determination Of γ-aminobutyric Acid"
Anal. Lett. 1995 Volume 28, Issue 2 Pages 259-266
Horie, H.;Rechnitz, G.A.

Abstract: Samples (20 µL) were mixed with 20 µL 2.5 µM-NADP/10 µM-2-oxoglutarate and injected into a carrier stream (0.1 or 0.8 ml/min) of 50 mM Tris hydrochloride buffer of pH 8 containing 1 mM 2-mercaptoethanol and 200 mM Na2SO4 which passed to an enzyme reactor. The reactor comprised a column (3.5 cm x 3 mm i.d.) packed with 200 mg glutaraldehyde-treated glass beads that had been mixed with 80 mg/ml GABAse (4-aminobutyrate:2-oxoglutarate aminotransferase and succinic semialdehyde:NADP+ oxidoreductase) in 0.2 mL 50 mM sodium phosphate buffer of pH 7 overnight, then washed with phosphate buffer. The NADPH produced was determined fluorimetrically at 460 nm (excitation at 360 nm). The calibration graphs were linear from 1-500 and 0.5-500 µM-γ-aminobutyric acid (GABA) at 0.8 and 0.1 ml/min, respectively. No RSD are given. At 0.8 ml/min samples could be injected every minute. The enzyme reactor retained >60% activity over 10 days. Recoveries of GABA from spiked green tea infusions were 97-104% at a flow rate of 0.1 ml/min.
4-aminobutyric acid Plant Fluorescence

"'Reagentless' Flow Analysis Determination Of Hydrogen Peroxide By Electrocatalysed Luminol Chemiluminescence"
Anal. Lett. 1997 Volume 30, Issue 1 Pages 21-31
James E. Atwater; James R. Akse; Jeffery DeHart; Richard R. Wheeler Jr.

Abstract: A schematic diagram is shown of the flow system. water carrier stream was passed sequentially through a 2.5 mL solid-phase basification (SPB) bed, a 0.5 mL crystallized luminol bed and a 5 mL SPB bed. The resulting carrier stream contained 50 mg/l of luminol of pH 10.3 and was mixed with the sample stream (3:2) just before the electrochemiluminescence cell. The chemiluminescence reaction was electrocatalyzed by a potential of ~0.6 V with a Au foil working electrode, a Au mesh counter electrode and a Ag/AgCl reference electrode. The calibration range extended from 0.033-16.65 mg/l of H2O2 (graph shown). The method should be applicable to both continuous-flow and flow injection systems.
Hydrogen peroxide Chemiluminescence Electrode

"Enzymic Determination Of Ethanol Using 'reagentless' Electrocatalyzed Luminol Chemiluminescence"
Anal. Lett. 1997 Volume 30, Issue 8 Pages 1445-1453
NAJames E. Atwater; James R. Akse; Jeffrey DeHart; Richard R. Wheeler Jr.

Abstract: The carrier stream comprised water (4.5 ml/min) flowing sequentially through a 2.5 mL solid-phase basification (SPB) bed, a 0.5 mL crystallized luminol bed and a 5 mL SPB bed. The resulting carrier stream comprised 50 mg/l luminol of pH 10.3. The sample stream consisted of water, equilibrated with atmospheric O2 containing aqueous ethanol was passed through a 1.2 mL immobilized alcohol oxidase bed at a rate of 3 ml/min corresponding to a carrier stream-to-analyte stream flow ratio of 3:2. The carrier and analyte streams were mixed at the inlet of the electrocatalyzed chemiluminescence cell. The intensity of the resulting chemiluminescence was measured by a photomultiplier tube. The method was suitable for the determination of aqueous ethanol concentrations ranging from 3-340 µM.
Ethanol Water Chemiluminescence

"Amperometric Flow Injection Analysis Of L-glutamate Using An Immobilized-enzyme Reactor: Amplification By Substrate Recycling"
Electroanalysis 1990 Volume 2, Issue 7 Pages 563-565
Toshio Yao*, Naokazu Kobayashi, Tamotsu Wasa

Abstract: A column (5 mm x 4 mm i.d.) of LiChrosorb NH2 (10 µm) was activated by circulation of 5% glutaraldehyde solution in 0.05 M NaHCO3 for 1.5 h, then washed with 0.1 M phosphate buffer of pH 7.0 before co-loading with glutamate oxidase (8.5 iu) and alanine aminotransferase (118 iu) by circulation of the enzyme solution in the same buffer for 2 h at room temperature The resulting reactor was washed for 3 h with 0.1 M glycine buffer of pH 7.5, and was stored in the 0.1 M phosphate buffer at 5°C when not in use. The reactor was positioned between the injector and a Yanagimoto flow-through Pt electrode in the flow injection system described previously (Anal. Chim. Acta, 1990, 231, 121) for the determination of L-glutamate with use of 1 mM L-alanine in 0.1 M phosphate buffer (pH 7.2) as carrier solution and an applied potential of 0.5 V vs. Ag - AgCl. The reaction principle is described. At the optimum reactor temperature of 37°C and a flow rate of 0.3 mL min-1, the amplification factor was 24; the detection limit was 0.1 µM and the calibration graph was curvilinear. The method could also be used to determine 2-oxoglutarate.
l-Glutamate Amperometry Electrode Electrode

"Use Of Chemically Modified Electrodes For Liquid Chromatography And Flow Injection Analysis"
Electroanalysis 1991 Volume 3, Issue 1 Pages 1-11
Erkang Wang, Huamin Ji, Weiying Hou

Abstract: The use of chemically modified electrodes (CMEs) for liquid chromatography and flow-injection analysis is reviewed. Electrochemical detection with CMEs based on electrocatalsis, permselectivity, ion flow in redox films, and ion transfer across the water-solidified nitrobenzene interface is discussed in terms of improving the stability, selectivity, and scope of electrochemical detectors and the detection of electroinactive substances. More than 90 references are included.
LC Electrode

"Highly Sensitive Determination Of L-lactate And Pyruvate By Liquid Chromatography And Amperometric Detection With Lactate Oxidase [lactate 2-monooxygenase] - L-lactate Dehydrogenase-co-immobilized Reactor Involving Amplification By Substrate Recycling"
Electroanalysis 1991 Volume 3, Issue 6 Pages 493-497
Toshio Yao, Naokazu Kobayashi, Tamotsu Wasa

Abstract: Pyruvate (I) and L-lactate (II) were determined in 10 µL of sample solution by flow injection reversed-phase HPLC on a column (25 cm x 4.6 mm) of ODS-T with 0.02 M phosphate buffer (pH 2.5) as mobile phase (0.4 mL min-1). Post-column reaction was carried out with 0.2 M phosphate buffer (pH 7.3) containing 0.5 mM NADH (0.25 mL min-1). The eluate was passed to the cited co-immobilized enzyme reactor where the I and II were recycled enzymatically to produce a large amount of H2O2. This was detected amperometrically at 0 V vs. Ag - AgCl by using a flow-through peroxidase electrode and mixing with 0.1 M phosphate buffer (pH 7.3) containing 0.5 mM K4Fe(CN)6 as mediator, pumped at 0.5 mL min-1. The detection limit was 0.02 pmol and the calibration graphs were rectilinear in the range 0.2 to 200 pmol for both I and II. The coefficient of variation was ~3.8% for 2 pmol of I or II (n = 5).
l-Lactate Pyruvate Amperometry HPLC Electrode

"Determination Of Sterigmatocystin In Fermentation Broths By Reversed-phase High Performance Liquid Chromatography Using Post-column Fluorescence Enhancement"
J. Chromatogr. A 1990 Volume 523, Issue 1 Pages 305-311
Frank L. Neely* and Curt S. Emerson

Abstract: Sterigmatocystin (I, fungal toxin often found in food) was separated from the broth by homogenization with methanol, filtration, extraction of I from the filter-cake with methanol and 0.45 µm re-filtration of the supernatant solution A portion of solution was subjected to HPLC in a column (25 cm x 4.6 mm) of Beckman Ultrasphere C18 (5 µm) with use of a guard column (1.5 cm x 3.2 mm) of Brownlee Newguard RP-18 (7 µm), a mobile phase (0.5 mL min-1) of aqueous 88% methanol, post-column derivatization (reaction coil diameter 0.01 in.) at 35°C with aqueous 5% AlCl3 (added at 0.5 mL min-1) and fluorimetric detection at 455 nm (excitation at 254 nm). The limit of detection was 0.09 ppm, with rectilinear calibration range from 0.1 to 15 ppm and coefficient of variation (n = 12) of 0.2% at 0.82 ppm. A TLC separation on Whatman LK-5D silica with a mobile phase of 1% acetic acid in CCl4 - CHCl3 (1:1) and fluorimetric detection of the same derivative is summarized.
Sterigmatocystin Fermentation broth HPLC Fluorescence Sample preparation

"Separation Of Free Amino-acids By Reversed-phase Ion-pair Chromatography With Column Switching And Isocratic Elution"
J. Chromatogr. A 1990 Volume 507, Issue 1 Pages 95-101
Mitsuko Hirukawa, Masako Maeda and Akio Tsuji, Toshihiko Hanai

Abstract: Seventeen free amino-acids were separated in 35 min by ion-pair chromatography using two columns: an Inertsil phenyl column (5 cm x 4.6 mm) for hydrophobic and basic amino-acids, and an Inertsil ODS-2 column (25 cm x 4.6 mm) for polar acidic and small amino-acids. Two eluents, viz. 50 mM Na phosphate buffer (pH 2.7) containing 6.5% of ethanol, 6.5% of acetonitrile and 0.11 M NaCl and the same buffer containing 25.6 mM Na dodecyl sulfate plus 12% of methanol and 94 mM NaCl, were used isocratically at 1 mL min-1. After post-column derivatization with phthalaldehyde, the amino-acids were determined by fluorescence at 450 nm (excitation at 340 nm); detection limits were 2 to 5 pmol for those with shorter retention times. Calibration graphs were rectilinear up to 500 pmol. The method was applied to bovine serum albumin hydrolysate, and results agreed well with literature values with results from LC.
Amino Acids Cow Serum HPLC Fluorescence

"Chemical Reaction Detection Of Catechins And Proanthocyanidins With 4-dimethylaminocinnamaldehyde"
J. Chromatogr. A 1989 Volume 467, Issue 1 Pages 185-193
D. Treutter

Abstract: The cited flavanols were determined in crude plant extracts and beverages by HPLC on a column (25 cm x 4 mm) of Hypersil ODS (3 µm), with gradient elution from 5 to 90% of methanol in 5% acetic acid. Post-column derivatization was carried out with 1% 4-dimethylaminocinnamaldehyde solution in methanolic 1.5 M H2SO4 and detection was at 640 nm. Sensitivity was improved 200 to 40,000-fold for (-)-epicatechin compared with other phenols and substituted indoles; the detection limit was 2.5 ng. For terpenes, this factor ranged from 4000 to 2,000,000. The selective detection of catechins and proanthocyanidins extracted from tea and beer is described.
Catechins Proanthocyanidins Beer Tea HPLC Spectrophotometry

"Determination Of Pseudouridine In Human Urine And Serum By High Performance Liquid Chromatography With Post-column Fluorescence Derivatization"
J. Chromatogr. A 1990 Volume 515, Issue 1 Pages 495-501
Yoshihiko Umegae, Hitoshi Nohta and Yosuke Ohkura

Abstract: Urine (100 µL) was mixed with 100 µL of 0.5 mM 5-fluorouridine (I; internal standard) and 800 µL of water. Serum (0.5 ml) was mixed with 0.5 mL of 0.05 mM I and 0.5 mL of 2 M HClO4, and the mixture was centrifuged at 1000 g and 4°C for 10 min. The supernatant solution (0.5 ml) was mixed with 65 µL of 2 M K2CO3 and re-centrifuged. An aliquot (100 µL) of either solution was analyzed by HPLC on a column (15 cm x 4.6 mm) of TSK gel ODS-80 (5 µm), with 2 or 4% of methanol in 10 mM phosphate (pH 5.0) as mobile phase (0.5 mL min-1). Detection was at 254 nm, and, after mixing the eluate with 2 mM NaIO4 and 20 mM 1,2-bis-(4-methoxyphenyl)ethylenediamine (each at 0.25 mL min-1), by fluorimetry at 470 nm (excitation at 340 nm). Calibration graphs were rectilinear for 0.5 to 50 nmol of pseudouridine in 100 µL of urine or 0.1 to 4 nmol of I in 0.5 mL of serum. Limits of detection were 40 and 8 nM, respectively.
Pseudouridine Urine Serum Human HPLC Fluorescence

"Simultaneous High Performance Liquid Chromatographic Determination Of Catecholamine-related Compounds By Post-column Derivatization Involving Coulometric Oxidation Followed By Fluorescence Reaction"
J. Chromatogr. A 1989 Volume 467, Issue 1 Pages 237-247
Hitoshi Nohta, Etsuko Yamaguchi and Yosuke Ohkura, Hideo Watanabe

Abstract: Noradrenaline, adrenaline, dopamine, L-dopa, O3-methylnoradrenaline, O3-methyladrenaline, 3-methoxytyramine, 3,4-dihydroxymandelic acid, 3,4-dihydroxyphenylacetic acid, 4-hydroxy-3-methoxyphenylacetic acid, 4-dihydroxymandelic acid, 3,4-dihydroxyphenylethanediol, 4-hydroxy-3-methoxyphenylethanediol and 4-hydroxy-3-methoxyphenylethanol were determined by the cited method. These compounds, and 3,4-dihydroxybenzylamine and ferulic acid as possible internal standards, were separated within 35 min by ion-pair reversed-phase HPLC on a column (15 cm x 4.6 mm) of TSK-gel ODS-80TM (5 µm) with a gradient of aqueous 20% methanol - acetonitrile (3:2; pH 3.1) in 60 mM citric acid - 32 mM Na2HPO4 - 1.7 mM Na hexanesulfonate - 0.1 mM Na2EDTA (pH 3.1). The compounds in the eluate were oxidized at a carbon-cloth electrode at 0.68 V, the O-quinones formed were treated with 20 mM 1,2-diphenylethylenediamine in 50 mM HCl and aqueous 1 M glycine - 0.49 M KOH - 3 mM K3Fe(CN)6, and the fluorescence was measured at 480 nm (excitation at 345 nm). The detection limits on-column were 1.5 to 4 pmol for the two mandelic acids, 600 fmol for L-dopa and 20 to 70 fmol for the other compounds.
Catecholamines HPLC Fluorescence Coulometry Sample preparation

"Rapid And Sensitive Determination Of Nucleoside H-phosphonates And Inorganic H-phosphonates By High Performance Liquid Chromatography Coupled With Flow Injection Analysis"
J. Chromatogr. A 1990 Volume 507, Issue 1 Pages 103-111
Yoshinobu Baba, Mitsutomo Tsuhako, and Norimasa Yoza

Abstract: A solution (100 µL) containing phosphate, phosphonate, hypophosphonate and isohypophosphonate was injected into a stream (1 mL min-1) of 0.1 to 0.3 M KCl containing 0.1% of Na4EDTA, and the phosphonates were separated on a column (25 cm x 4.0 mm) of TSKgel SAX (10 µm) and then mixed with chromogenic reagent (MoV - Mo(VI); 0.8 mL min-1) and oxidizing agent [aqueous NaHSO3 (104 g l-1); 0.2 mL min-1]. After detection at 260 nm, the solution was passed through a 20-m reaction coil at 140°C and the absorbance of the heteropoly blue complex was measured at 830 nm. The detection limit was ~1 µM for inorganic, sugar and nucleoside phosphonates.
Phosphonates HPLC Spectrophotometry

"Simultaneous Determination Of Biogenic Amines By Reversed-phase High Performance Liquid Chromatography"
J. Chromatogr. A 1990 Volume 508, Issue 1 Pages 225-228
Satoru Suzuki, Kentaro Kobayashi, Junko Noda, Tetsuya Suzuki and Kozo Takama

Abstract: The method of Gamoh and Fujita (Shimadzu Rev., 1987, 44, 237) was modified for the determination of histamine and five other biogenic amines in herring muscle. Dried herring (5 g) was homogenised with 10% trichloroacetate acid (2 x 20 ml), centrifuged at 550 g for 20 min, and the combined extracts were diluted to 50 mL. A portion (5 µL) of the solution was analyzed by HPLC on a column (15 cm x 6 mm) of Shim-Pak CLC-ODS operated at 50°C with gradient elution (1.1 mL min-1) with (i) 0.01 M Na hexanesulfonate in 0.1 M NaClO4 (pH 4.0) and (ii) a mixture of (i) - methanol (1:3) adjusted to pH 3.0 (details given). After post-column o-phthalaldehyde derivatization fluorimetric detection was at 455 nm (excitation at 345 nm). The method can also be applied in clinical analyzes.
Amines, biogenic Histamine Muscle Clinical analysis HPLC Fluorescence Sample preparation

"High Performance Liquid Chromatographic Determination Of Proteins By Post-column Fluorescence Derivatization With Thiamine Reagent"
J. Chromatogr. A 1990 Volume 518, Issue 1 Pages 141-148
Toshio Yokoyama, Toshio Kinoshita

Abstract: Proteins in the 70% (NH4)2SO4 fraction of Escherichia coli cell debris were separated on a column (30 cm x 7.5 mm) of TSKgel-G3000SW, with 0.1 M phosphate buffer (pH 7.5) containing 0.1 M Na2SO4 as mobile phase (0.8 mL min-1). The column eluate was mixed with a stream (0.2 mL min-1) of hypochlorite reagent (NaOCl solution containing 0.05 M phosphate buffer of pH 7.5 and 0.1% of Brij-35, adjusted to pH 7.5 and 0.8% available Cl, and chlorination was performed online at 70°C in a PTFE reaction coil. The reaction stream was then mixed online with thiamine reagent (0.2 mL min-1, comprising 4% NaNO2 - 0.02% of thiamine hydrochloride in 0.05 M phosphate buffer of pH 7.5), thiochrome was produced in a second reaction coil at 70°C, and the fluorescence generated was monitored at 440 nm (excitation at 370 nm). Calibration graphs for five proteins were rectilinear from 20 ng to 2 µg injected, and the detection limit of bovine serum albumin was 10 ng. Ionic surfactants did not interfere.
Fluorescence HPLC

"Liquid Chromatographic Determination Of Felypressin Using A Column-switching Technique And Post-column Derivatization"
J. Chromatogr. A 1990 Volume 521, Issue 1 Pages 141-147
Mats Svensson* and Kerstin Gr&ouml;ningsson

Abstract: The nonapeptide felypressin (I) was determined in a dental anaesthetic containing prilocaine hydrochloride after cartridge cleanup. The cartridge (25 mm x 4 mm) packed with Superspher 60 RP-8 (4 µm; Merck) was connected in series with the analytical column (5 cm x 4 mm) of Superspher 60 RP-8e (4 µm). During cleanup (14 min) the mobile phase (1 mL min-1) of phosphate buffer (pH 6.0) - acetonitrile (22:3) was fed through the cartridge only, then flow was switched through cartridge and column and solvent component ratio was changed to 4:1 for the analytical phase (9 min). Post-column derivatization was by addition of 0.03% (w/v) of fluorescamine and 0.1% (v/v) of Brij 35 in acetonitrile (0.25 mL min-1) and fluorimetric detection was at 470 nm (excitation at 390 nm). For determination of I in Citanest Octapressin injection solution, coefficient of variation were 1.7% and mean recovery was 101.8% (n = 6). Life of the cleanup cartridge was ~100 determinations.
Felypressin Anaesthetic LC Fluorescence

"Determination Of Organophosphorus And Carbamate Pesticide Standards By Liquid Chromatography With Detection By Inhibition Of Immobilized Acetylcholinesterase"
J. Chromatogr. A 1991 Volume 539, Issue 1 Pages 47-54
M. E. Leon-Gonzalez and Alan Townshend

Abstract: Pesticides were separated on a column (25 cm x 4.6 mm) of Spherisorb S10 ODS2 (10 µm), with aqueous 50% THF as mobile phase (0.7 mL min-1), and spectrophotometric detection with use of the flow injection immobilized acetylcholinesterase system described previously (Anal. Chim. Acta, 1990, 236, 267). Detection limits and rectilinear calibration ranges were 2.6 and 5 to 40 ng for paraoxon, 0.04 and 0.1 to 1.6 ng for di-isopropyl fluorophosphate, 18 and 20 to 100 ng for isopropyl N-phenylcarbamate and 29 and 40 to 400 ng for isopropyl N-(3-chlorophenyl)carbamate. The cited pesticides are separated in 16 min, and the enzyme column can be used for 90 analyzes.
Pesticides, carbamate Pesticides, organophosphorus LC Spectrophotometry

"Optimized High Performance Liquid Chromatographic Procedure For The Separation And Quantification Of The Main Folacins And Some Derivatives. I. Chromatographic System"
J. Chromatogr. A 1991 Volume 540, Issue 1-2 Pages 207-215
A. Hahn, J. Stein, U. Rump and G. Rehner

Abstract: Folates (folacins) were separated and determined by HPLC in a column (25 cm x 4.6 mm) of Hypersil ODS (3 µm) with use of a C-135B pre-column (Upchurch Scientific, Oak Harbour, WA, USA) containing Hypersil ODS (10 µm), a gradient mobile phase (0.9 mL minmin1) of aqueous 5 mM KH2PO4 (pH 2.3) - acetonitrile (93:7 to 87:13 over 15 min, then to 81:19 in 3 min and to 79:21 in 3 min) and detection at 295 nm or by fluorimetry at 356 nm (excitation at 295 nm) or for post-column derivatives at 450 nm (excitation at 365 nm). Post-column derivatization to pterins was with 1% H2S2O8 in a PTFE coil (10 m x 0.8 mm) at 60°C. Lower detection limits for folates were from 1.1 to 2.7 (295 nm) or 0.007 to 0.89 ng injected (356-nm fluorimetry). Methotrexate and 3',5'-dichlorofolic acid were used as internal standards.
Folacins HPLC Fluorescence

"Preconcentration Of Divalent Trace Metals On Chelating Silicas Followed By Online Ion Chromatography"
J. Chromatogr. A 1991 Volume 541, Issue 1-2 Pages 443-452
D. Chambaz, P. Edder and W. Haerdi

Abstract: For online pre-concentration of the cited metals, a titanium pre-column (1.3 cm x 1.7 mm or 5 cm x 2 mm) of ethylenediamine triacetate-bonded silica (prep. described) was used, with adsorption from a mobile phase of 0.1 M acetate buffer (pH 5.0) and desorption with 0.1 M HNO3. The eluate was adjusted to pH 3.0 with 0.5 M tartaric acid for use as mobile phase for HPLC on a column (30 cm x 4 mm) of Nucleosil 10SA with post-column derivatization with 4-(2-pyridylazo)resorcinol in a PTFE coil (3 m x 0.5 mm) and detection at 500 nm. Calibration graphs for Co, Ni, Cu, Zn, Cd and Pb were rectilinear from 3 nM to 3 µM; the method was applied to river water.
Cadmium Cobalt Copper Lead Nickel Zinc River HPIC Spectrophotometry

"Analysis Of Paralytic Shellfish Poisons By Capillary Electrophoresis"
J. Chromatogr. A 1991 Volume 542, Issue 2 Pages 483-501
P. Thibault, S. Pleasance and M. V. Laycock

Abstract: Underivatized saxitoxin (I) and neosaxitoxin (II) were separated by capillary electrophoresis on a fused-silica capillary column (90 cm x 50 µm) with either sodium citrate buffer (20 mM, pH 2) or acetic acid (0.1M, pH 2.9); detection was at 200 nm. Sample introduction was performed using either hydrodynamic or electrokinetic injections. Identification of the electrophoretic peaks was confirmed by MS using ionspray ionization and by HPLC with fluorescence detection. The limits of detection were 15 and 18 pg for I and II, respectively; improvements in sensitivity are likely to be achieved using pre- or post-column fluorescent derivatization. Results for dinoflagellates and scallops are presented and are reproducible in terms of both migration times and sensitivity, comparing well with existing techniques.
Saxitoxin Neosaxitoxin Marine HPLC Electrophoresis Fluorescence Mass spectrometry

"Progress In Optimization Of Transition Metal Cation Chromatography And Its Application To Analysis Of Silicon Wafer Contamination"
J. Chromatogr. A 1991 Volume 546, Issue 1 Pages 243-249
Kenneth A. Ruth and Roger W. Shaw

Abstract: A PTFE extraction cell filled with 18.9 mM HF - 50 mM HCl - 4.9 mM H2O2 was subjected to ultrasonication and 11 mL samples were taken for background data. The silicon wafer is added, the cell is filled up with the above mixture and subjected to ultrasonic agitation for ~15 min. Two samples were taken and pre-concentrated on a Dionex TCC-1 trace cation concentrator. Separation was carried out on a Dionex HPIC-CS5 column with 3 mM pyridine-2,5-dicarboxylic acid - 4.3 mM LiOH - 2 mM Na2SO4 - 25 mM NaCl as eluent (1 mL min-1), 1 mM 4-(2-pyridylazo)resorcinol - aqueous 3 M NH3 (pH 11) as post-column derivatization reagent and detection at 520 nm. The second method described is a modification of that of Cassidy and Elchuck (Anal. Chem., 1982, 54, 1558). A PTPE tube held at 60°C was inserted after the addition of post-column reagents. Detection limits were 0.02 to 0.3 ppb by the first method and 0.05 to 0.2 ppm by the second method.
Silicon Chromatography

"Column Liquid Chromatographic Determination Of Saccharides With A Single Calibration Graph Using Post-column Enzyme Reactors And Coulometric Detection"
J. Chromatogr. A 1991 Volume 549, Issue 1 Pages 127-132
Nobutoshi Kiba, Kazuyoshi Shitara, Hiroshi Fuse, Motohisa Furusawa, and Yoshinori Takata

Abstract: Immobilized enzymes were used as column reactors in a column liquid chromatographic system for the specific detection of the saccharides stachyose, raffinose and sucrose. Invertase and fructose dehydrogenase (FDH) were immobilized onto poly(vinyl alcohol) beads and porous glass beads, respectively. The oligosaccharides were separated on a cation-exchange resin column with water as the mobile phase. Invertase was capable of quantitatively hydrolysing the oligosaccharides to fructose, which reacts with the hexacyanoferrate(III) ion in the presence of FDH. The hexacyanoferrate(II) ion produced was monitored coulometrically. A single calibration graph for fructose based on the peak area was used to determine each oligosaccharide. The limits of detection for stachyose, raffinose and sucrose were 27, 5 and 2 ng (in a 50 l sample), respectively.
Saccharides Amperometry LC Coulometry

"Determination Of Free Cyanide In Gold Cyanidation Process Liquors By Ion-interaction Chromatography With Post-column Derivatization"
J. Chromatogr. A 1991 Volume 550, Issue 1-2 Pages 559-571
Peter A. Fagan and Paul R. Haddad

Abstract: Leach liquor (10 µL) was applied to a column (15 cm x 4.6 mm) of Nova-Pak C18 with aqueous 25% acetonitrile in 5 mM low-UV PIC A as mobile phase (1 mL min-1). Cyano complexes of Cu(I), Fe(II), Ag(I), Fe(III) and Au(I) and thiocyanate were detected at 214 nm. Free CN- was detected in the void volume at 500 nm after online post-column reaction with N-chlorosuccinimide - succinimide and isonicotinic acid - barbituric acid. Three hardware configurations are described in the first of which the column eluate is passed directly to the post-column reactor. In the second system the eluate is passed to a valve allowing a selected portion of eluate to be passed to the post-column reactor. The third is the same as the second but with an ion-exclusion column (15 cm x 7.8 mm) inserted before the post-column reactor. Calibration graphs were rectilinear up to 300 ppm of free CN- by all three configurations. The coefficient of variation for determination of free CN- in leach liquor was 0.2%.
Cyanide, free Metal HPIC

"Sensitive Liquid Chromatographic Determination Of Alkyl-, Nitro- And Chlorophenols By Pre-column Derivatization With Dansyl Chloride, Post-column Photolysis And Peroxyoxalate Chemiluminescence Detection"
J. Chromatogr. A 1991 Volume 553, Issue 1 Pages 345-356
P. J. M. Kwakman, D. A. Kamminga and U. A. Th. Brinkman, G. J. De Jong

Abstract: Aqueous phenol-containing solution was adjusted to pH 12 with 1 M NaOH, treated with aqueous tetrabutylammonium bromide and dansyl chloride in CH2Cl2. After mixing, a portion of the organic phase was applied to an amino-bonded SPE column and the dansyl derivatives were eluted with CH2Cl2. The eluate was evaporated to dryness and the residue was dissolved in aqueous 50% methanol. A portion of the solution was analyzed by LC on a column (20 cm x 3.2 mm) of LiChrosorb RP-18 (3 µm) with methanol - imidazole buffer of pH 7 as eluent (gradient elution details given). After chromatography, the dansyl derivatives were irradiated in a photochemical reactor (cf. Scholten et al., ibid, 1980, 199, 239) before 2-nitrophenyl oxalate - H2O2 in acetonitrile were added to the column eluate (for chemical excitation); peroxyoxalate chemiluminescence detection at 470 nm (excitation at 340 nm) was used. The method was applied to determine several phenolic compounds in surface water; detection limits were 0.01 to 0.1 ng mL-1.
Phenols, alkyl Phenols, chloro Phenols, nitro Surface Chemiluminescence LC

"High Performance Liquid Chromatography Post-column Derivatization With Fluorescence Detection To Study The Influence Of Ambroxol On Dipalmitoylphosphatidylcholine Levels In Rabbit Eustachian Tube Washings"
J. Chromatogr. A 1991 Volume 553, Issue 1 Pages 1-6
M. Kitsos, C. Gandini, G. Massolini and E. De Lorenzi, G. Caccialanza

Abstract: Eustachian tube or lung washings (10 ml) were centrifuged and the supernatant solution was freeze-dried before CHCl3 (5 ml) was added. After filtration, the solution was dried under N and the residue was dissolved in methanol (500 µL). A 100 µL portion was analyzed by HPLC on a column (10 cm x 4.6 mm) of ODS Hypersil (5 µm) with isocratic elution with 40 µM-choline chloride in methanol and THF (1 mL min-1). Fluorescence detection was at 460 nm (excitation at 340 nm) with use of 1,6-diphenyl-1,3,5-hexatriene in THF and 0.001% of polysorbate 20 (1.2 mL min-1). Levels of dipalmitoylphosphatidylcholine were also determined after ambroxal chloride administration.
dipalmitoylphosphatidylcholine Lung HPLC Fluorescence

"Reversed-phase Separation Of Transition Metals, Lanthanoids And Actinoids By Elution With Mandelic Acid"
J. Chromatogr. A 1991 Volume 558, Issue 1 Pages 197-207
Steve Elchuk, Kerry I. Burns, Richard M. Cassidy and Charles A. Lucy

Abstract: A gradient concentration of 0.14 M to 0.50 M mandelic acid during 15 min was used in a mobile phase (1.0 mL min-1) of 0.01 M Na octanesulfonate at pH 4.0 for separation of lanthanoids in a column (10 cm x 4 mm) of Spherisorb C18 (3 µm), with post-column derivatization with arsenazo III for detection at 685 nm. The same column was used for separation of six actinoids in a mobile phase of 0.5 M mandelic acid in aqueous 5% acetonitrile (pH 3.2; no octanesulfonate) with similar derivatization and detection. Suitable operating concentration. were 1 mg L-1 for lanthanoids or 0.3 (Am) or 3.0 mg L-1 (others) for actinoids. Specimen chromatograms are presented and results are discussed.
Metals, actinides Metals, lanthanides Metals, transition HPLC Spectrophotometry

"Characterization Of Cellulase-based Enzyme Reactors For The High Performance Liquid Chromatographic Determination Of β-D-Glucan Oligosaccharides"
J. Chromatogr. A 1991 Volume 558, Issue 2 Pages 343-355
P. C. Maes, L. J. Nagels*, C. Dewaele, and F. C. Alderweireldt

Abstract: Post-column enzyme reactors were used in series with an electrochemical detector for the selective high-performance liquid chromatographic (HPLC) determination of --glucan oligo- and polysaccharides (degree of polymerization up to 30). Immobilized cellulase converted the eluting oligomers to --glucose, which was oxidized by immobilized glucose oxidase. The production of hydrogen peroxide was measured with an electrochemical detector. The functioning of this system was verified for a whole range of glucosaccharides varying in both structure (positional isomers) and degree of polymerization. Fractional conversions and molar response factors were determined for all the compounds under study. Rate constants are discussed for the reactor system used applying a first-order kinetics model. Efficient HPLC separations were obtained for these oligo- and polysaccharides on a reversed-phase column using gradient elution. Detection limits were of the order of a few nanograms. The reactors were stable for several months.
β-d-Glucan Amperometry HPLC Electrochemical analysis Electrode

"Detection Of Zearalenone In Cereal Extracts Using High Performance Liquid Chromatography With Post-column Derivatization"
J. Chromatogr. A 1991 Volume 588, Issue 1-2 Pages 47-52
Michael T. Hetmanski* and Keith A. Scudamore

Abstract: Sample extracts were prepared according to previous techniques (c.f., J. Assoc. Off. Anal. Chem., 1979, 62, 1265 and Food Addit. Contam., 1989, 6, 35) and analyzed by HPLC on a column (25 cm x 4.6 mm) of Spherisorb ODS-1 (5 µm) with a mobile phase (1 mL min-1) of aqueous 80% methanol. The eluate was derivatized in a PTFE coil with 0.25 M aluminum chloride solution at ~50°C and zearalenone and zearalenol were detected fluorimetrically at 440 nm (excitation at 285 nm). The described methods led to a 5-fold increase in the fluorescence response of the cited mycotoxins without significantly affecting the level of background interference from co-extractives from cereal and animal feed samples.
Zearalenone Feed Breakfast HPLC Fluorescence

"Potentiometric Detection Of Aliphatic Amines By Flow Injection Analysis And Ion-interaction Chromatography With A Metallic Copper Electrode"
J. Chromatogr. A 1997 Volume 758, Issue 2 Pages 227-233
ZuLiang Chen* and Peter W. Alexander

Abstract: The use of a metallic copper wire electrode for the detection of amines using FIA with octylammonium salicylate was studied. Effects on response by parameters such as, carrier pH, concentration of the ion-interaction reagent and injection volume were investigated. The electrode was applied to the determination of amines after ion-interaction chromatography on a Brownlee C18 column (10 cm x 4.6 mm) with 0.3 mM octylammonium salicylate/H2O of pH 6 as the mobile phase at a flow rate of 0.3 ml/min. Detection limits were from 0.5-1 nmol. Comparable results were obtained with UV detection.
Amines, aliphatic HPLC Potentiometry Electrode

"Simultaneous Amperometric And Potentiometric Detection Of Sugars, Polyols And Carboxylic Acids In Flow Systems Using Copper Wire Electrodes"
J. Chromatogr. A 1997 Volume 766, Issue 1-2 Pages 27-33
Z. -L Chen and D. B Hibbert*

Abstract: The use of polished Cu wire electrodes (3 cm x 0.5 mm o.d.) for electrochemical detection was evaluated by cyclic voltammetry and FIA with amperometric and potentiometric detection. Sugars and polyols were amperometrically detected at 0.5 V vs. Ag/AgCl in 100 mM NaOH; calibration graphs were linear from 1-1000 µM and detection limits were 2 pmol glycerol, 5 pmol fructose and glucose and 80 pmol ethanol. Carboxylic acids were potentiometrically detected in aqueous solution; calibration graphs were linear from 0.01-1 mM and detection limits were 10 pmol citric acid and 50 pmol acetic acid. The RSD (n = 5) were 2-3% for all analytes. The electrodes were then used in the analysis of a portion (10 µL) of a mixed solution of the analytes by ion-exclusion chromatography on a Bio-RAD HPX-87H column (dimensions not given) at 30°C with water of pH 5.5 as mobile phase (0.5 ml/min). The eluate was initially detected by potentiometry then merged with a flow (0.5 ml/min) of 100 mM NaOH solution prior to amperometric detection (chromatogram shown).
Carboxylic acids Polyols Sugars Glycerol Fructose Glucose Ethanol Citric acid Acetic acid Amperometry HPIC Potentiometry Electrode

"High Performance Liquid Chromatographic Analysis Of Unchanged Cis-diamminedichloroplatinum (cisplatin) In Plasma And Urine With Post-column Derivatization"
J. Chromatogr. B 1990 Volume 529, Issue 1 Pages 462-467
Masafumi Kinoshita, Naomi Yoshimura and Hiroyasu Ogata, Daijiro Tsujino, Toshiaki Takahashi, Satoru Takahashi, Yuji Wada and Kazuhiko Someya, Tetsuro Ohno, Keisou Masuhara and Yoshio Tanaka

Abstract: Plasma was ultra-filtered and analyzed directly. Urine was centrifuged and diluted 1:10 before analysis. HPLC was carried out on a column (15 cm x 4.6 mm) of Hitachi No. 3013-N anion-exchange resin (5 µm), with a Guard-Pak CN pre-column and acetonitrile - 10 mM NaCl (17:3) as mobile phase (0.7 mL min-1). The eluate was mixed with 26 µM-K2Cr2O7 (0.14 mL min-1) and 6.6 mM NaHSO3 (0.7 mL min-1), and cisplatin was determined as Pt by AAS at 265.9 nm (heating program given). The limit of detection was 80 ng mL-1 and the calibration graph was rectilinear for 30 µg mL-1. Recovery was 95.0 to 104.0% from plasma and 98.0 to 103.8% from urine, with corresponding coefficient of variation of 4.9 to 7.9% and 3.0 to 5.5%. The method is applicable to pharmacokinetic studies.
Blood Plasma Urine HPLC

"Reversed-phase High Performance Liquid Chromatographic Method For The Measurement Of Polyamine Oxidase Activity"
J. Chromatogr. B 1990 Volume 533, Issue 1 Pages 187-194
Allan G. Halline and Thomas A. Brasitus

Abstract: Cytosolic fractions of small intestinal or colonic mucosa was incubated at 37°C for up to 60 min with glycine, dithiothreitol, N'-acetylspermidine, aminoguanidine and pargyline. The reaction was stopped by addition of trichloroacetic acid and the mixture was filtered and subjected to HPLC on an Ultrasphere ion-pair column (25 cm x 4.6 mm) with a Guard-Pak pre-column module and a Waters C18 cartridge. Gradient elution (1 mL min-1) was from 65 to 100% of 0.2 M Na acetate of pH 4.5 (I) - acetonitrile (10:3) containing 10 mM octanesulfonic acid (II) in 0.1 M I containing 10 mM II. Post-column derivatization was with o-phthalaldehyde and fluorescence detection at 455 nm (excitation at 340 nm). Rapid and efficient separation of N'-acetylspermidine and putrescine (reaction product).
Enzyme, polyamine oxidase HPLC

"High Performance Liquid Chromatographic Determination Of Clenbuterol And Cimaterol Using Post-column Derivatization"
J. Chromatogr. B 1991 Volume 564, Issue 2 Pages 537-549
Dirk Courtheyn*, Carlo Desaever and Roland Verhe

Abstract: Animal tissues, faeces and feeding-stuffs were extracted with dilute 0.5 M HCl saturated with ethyl acetate; the resulting extracts or liquid samples, e.g., urine, plasma, blood and bile were purified on Chem Elut CE 120 columns and eluted with toluene - CH2Cl2. The eluate was mixed with 0.1 M HCl, ultrasonicated and centrifuged before a portion of the mixture was analyzed by HPLC on a column (15 cm x 4.6 mm) of Nova-Pak C18 (4 µm) with 25 mM sodium dodecyl sulfate and 0.02 M anhydrous acetic acid buffer of pH 3.5 containing 1 M NaOH - acetonitrile (53:47) as mobile phase (1.3 mL min-1). The eluate was derivatized with use of three reagents (details given) before the absorbance was measured at 537 and 493 nm for cimaterol and clenbuterol, respectively. Detection limits for liquid and solid samples were 0.1 ng mL-1 and 0.2 ng g-1, respectively. Results agreed well with those obtained by high performance TLC and GC - MS.
Cimaterol Clenbuterol Bile Blood Blood Plasma Urine Faeces Biological tissue Feed HPLC Spectrophotometry

"Determination Of Ampicillin In Biological Fluids By Coupled-column Liquid Chromatography And Post-column Derivatization"
J. Chromatogr. B 1991 Volume 567, Issue 1 Pages 121-128
K. Lanbeck-Vall&eacute;n*, J. Carlqvist and T. Nordgren

Abstract: Plasma (0.5 ml) was mixed vigorously with 70% trichloracetic acid in Na2PO4 - citric acid buffer solution, pH 5.4 (200 µL) and centrifuged at 2400 g for 10 min. A portion (400 µL) of the supernatant liquid was mixed with 1 M NaOH (85 µL) to adjust the pH to ~5. Paediatric plasma (100 µL) was treated in a similar manner. Urine was diluted with 0.5 M Na2PO4 - citric acid buffer solution of pH 4.85. Portions (20 to 100 µL) of the solution were analyzed by HPLC on a column of Perkin Elmer 3 x 3 (3 µm) connected in series with a column (10 cm x 4.6 mm) of Microspher C18 (3 µm) with elution (1 mL min-1) with 17% methanol in phosphate buffer solution of pH 7.4 containing 1 mM Na hexylsulfate for the first column and 35% methanol (for plasma) or 30% methanol (for urine) in phosphate buffer solution of pH 7.4 for the second column. The eluate from the second column was reacted with fluorescamine (0.16 mg mL-1) in acetonitrile and the fluorescence was measured at 470 nm (excitation at 372 nm). Detection limits were 14 nM and 570 nM-of ampicillin in plasma and urine, respectively.
Ampicillin Blood Plasma Urine HPLC Fluorescence

"Determination Of Neomycin In Plasma And Urine By High Performance Liquid Chromatography. Application To A Preliminary Pharmacokinetic Study"
J. Chromatogr. B 1991 Volume 571, Issue 1-2 Pages 189-198
Badar Shaikh*, Jean Jackson and Greg Guyer, William R. Ravis

Abstract: Plasma (1 ml) was deproteinized with 20% trichloroacetic acid solution and the solution was centrifuged. The urine sample was also centrifuged and both supernatant solution were analyzed on a column (15 cm x 4.6 mm) of Supelcosil LC-8-DB (5 µm). A guard column (2 cm x 4.6 mm) of LC-8-DB Supelguard was also used. The mobile phase consisted of 11 mM 1-pentanesulfonate, 56 mM Na2SO4, 7 mM acetic acid and 1.5% of methanol. Neomycin (I) was determined following post-column derivatization with phthalaldehyde at 33°C and fluorescence detection at 455 nm (excitation at 340 nm). Calibration graphs were rectilinear from 0.3 to 20 µg mL-1 of I. The average intra- and inter-assay coefficient of variation for I were 4.4 and 9.8%, respectively.
Neomycin B Blood Plasma Urine HPLC Fluorescence

"Desorption Studies At A Hanging Mercury Drop Electrode By A Flow Injection Method"
J. Electroanal. Chem. 1990 Volume 283, Issue 1-2 Pages 421-424
Hiromiti Sawamoto and Keiji Gamoh

Abstract: A block diagram for the flow injection method is shown. The supporting electrolyte solution (usually 0.1 M KCl), from which O is removed, is placed in the reservoir. An active charcoal column is placed between the peristaltic pump and the injection valve to remove traces of surfactants dissolved in the supporting electrolyte solution. The most important part of the app. is the voltammetric cell, which is made from a Teflon cylinder in which a hanging Hg drop electrode, a calomel electrode, and a Pt electrode are placed. Surfactants are introduced via the injection valve and differential-capacitance-time (C vs. t) curves are measured in the voltammetric cell. The decrease in differential capacitance shows the adsorption of the surfactant. The C vs. t curves for Hg at -0.6 V in 0.1 M KCl with and without additions of saturated n-octyl alcohol and vitamin B12 are shown. The adsorption of the n-octyl alcohol is reversible while that of vitamin B12 is not.
1-Octanol Vitamin B12 Electrode

"Spectrophotometric Determination Of Adrenaline With An Oxidative Column In A FIA Assembly"
J. Pharm. Biomed. Anal. 1990 Volume 8, Issue 8-12 Pages 663-666
A. Kojo and J. Martinez Calatayud*

Abstract: A single channel FIA assembly is proposed for the spectrophotometric determination of adrenaline, the aqueous sample solution is directly injected into the carrier stream leading the sample through a manganese dioxide column at 80°C, and on to the spectrophotometer flow-cell. The calibration graph is linear up to 17 ppm of adrenaline. The influence of other substances has been studied and the method has been applied to the determination of adrenaline in a pharmaceutical formulation. Sample solution (348.8 µL) was injected into a carrier stream (0.55 mL min-1) of distilled and de-areated water and passed through a column of MnO2, the carrier solution, sample loop and column were maintained at 80°C. The absorbance of the oxidized sample was measured at 300 nm. The calibration graph was rectilinear up to 17 ppm of adrenaline and the detection limit was 0.05 ppm. Coefficient of variation was 0.19% (n=11). Sample throughput was 45 h-1. Interference was present from procaine, amethocaine and picric acid.
Adrenaline Pharmaceutical Spectrophotometry

"FIA - Fluorimetric Determination Of Thiamine"
J. Pharm. Biomed. Anal. 1990 Volume 8, Issue 8-12 Pages 667-670
J. Martinez Calatayuda,*, C. Gomez Benitob and D. Gaspar Gimeneza

Abstract: Sample solution (137.3 µL) was injected into a carrier stream (0.74 mL min-1) of Na2CO3 - boric acid (pH 10) into a coil column (225 cm length) containing immobilized hexacyanoferrate on an ion-exchange resin (cf., Calatayud and Sagrado Vives, Ibid., 1989, 7, 1165) and the fluoresence of the eluate was measured at 440 nm (excitation at 368 nm). Calibration graphs were rectilinear from 0.1 to 4.0 ppm of thiamine. Coefficient of variation was 1.8%. Sample throughput was 28 h-1. Other vitamins, e.g. riboflavin, nicotinamide, pyridoxin, and certain other substances, e.g. caffeine, gave errors of up to 4.3%. A flow injection fluorimetric determination of thiamine is reported. The procedure is based on the oxidation of the analyte with potassium hexacyanoferrate(III) immobilized on an anionic exchange resin; the fluorescence is monitored in aqueous basic solution. Concentrations of the vitamin of 0.1-4 ppm have been determined; the relative standard deviation was 1.8%. The injection rate was 28 samples/h. The influence of other substances and the determination of the drug in a pharmaceutical formulation are also reported.
Thiamine Pharmaceutical Fluorescence Ion exchange

"An Online Immunoassay Method For Theophylline Using A Protein A Immunoreactor"
J. Pharm. Biomed. Anal. 1991 Volume 9, Issue 10-12 Pages 1121-1123
Pilar Fernandez-Hernando and James N. Miller

Abstract: A heterogeneous fluorescence immunoassay for theophylline has been automated using a flow injection analysis system containing a protein A solid phase reactor to separate antibody-bound and unbound fluorescein-theophylline. For each sample the antibody-protein A reaction takes place at near neutral pH, and the complexes are eluted at acid pH. The antibody-binding capacity of the reaction greatly exceeds the antibody level in each sample incubation mixture, and a single reactor can be repeatedly cycled between neutral and acid pHs. Experimental variations such as reactor size, flow rate, pH values, and reactant concentrations have been studied. Theophylline could readily be determined at the µg mL-1 level with online incubation with antibodies. Sheep anti-theophylline antiserum, serum sample and fluorescein isothiocyanate-theophylline were injected into a carrier stream of 50 mM Tris - HCl buffer of pH 8.8 containing 0.1 M NaCl. The mixture passed through a column (5 cm x 3 mm) of protein A immobilized on controlled pore glass particles; elution was effected by the injection of 0.5 M citrate buffer of pH 3.5 containing 0.1 M NaCl. The eluate was detected fluorimetrically at 525 nm (excitation at 495 nm). The flow rate was 0.2 mL min-1 throughout. Recoveries of theophylline were 80.5 to 94.8% and the within- and between-day coefficient of variation (n = 10) were both 7.9%.
Theophylline Fluorescence Immunoassay

"Flow Injection Immunoassay Using A Protein A Immunoreactor"
J. Pharm. Biomed. Anal. 1991 Volume 9, Issue 10-12 Pages 1115-1120
J. N. Miller, D. A. Palmer and M. T. French

Abstract: Competitive immunoassay have been developed for the determination of cyclosporin A (I) and theophylline (II) using microcolumns of protein A immobilized on controlled pore glass and flow injection techniques. For cyclosporin, the assay was based on a monoclonal antibody with fluorimetric detection; for theophylline, sheep antiserum and electrochemical detection was used. The limits of detection were 9 ng mL-1 of I and 2.5 µg mL-1 of II.
Cyclosporin A Theophylline Electrochemical analysis Fluorescence Immunoassay

"Spectrophotometric Determination Of Promazine With An Oxidative Column In FIA Manifolds"
J. Pharm. Biomed. Anal. 1992 Volume 10, Issue 10-12 Pages 785-788
Anatol Kojlo*, Helena Puzanowska-Tarasiewicz and J. Martinez Calatayud

Abstract: Two flow injection methods for the determination of promazine hydrochloride (I), using MnO2 oxidative columns and spectrophotometric detection of the oxidation product at 513 nm were developed. Method (i) involved direct sample injection (250 µL) into a HCl carrier stream by a loop-valve injector; in this instance the oxidative column (11 cm x 1 mm) was placed between the sample injector and the detector. Method (ii) involved the introduction of the sample into the sample loop which also acted as the oxidative column (optimum length 24 cm). In both methods a HCl carrier stream of pH 1.6 was used at a flow rate of 0.8 mL min-1. Calibration graphs were rectilinear from 2 to 20 mg L-1 and from 1 to 6 mg L-1 of I for methods (i) and (ii), respectively; corresponding detection limits were 0.1 and 0.03 mg l-1. Sampling rates were 62 and 80 h-1 for methods (i) and (ii), respectively. Results obtained compared well with those of the method of Blasek and Kracmar (cf. Ceskoslov Farm., 1967, 16, 437). A simple flow injection spectrophotometric method for the determination of promazine is described. The two proposed procedures are based on the oxidation of analyte with a manganese dioxide column. Concentrations of promazine in the ranges 2-20 and 1-6 are determined with a relative standard deviation of 1.0%. The injection rates are 62 and 80 samples h-1, respectively. The influence of foreign species and the determination of promazine in a pharmaceutical formulation are also reported.
Promazine Pharmaceutical Spectrophotometry

"Environmental Immunoassay For The Explosive RDX Using A Fluorescent Dye-labelled Antigen And The Continuous-flow Immunosensor"
Sens. Actuat. B 1997 Volume 39, Issue 1-3 Pages 411-418
John C. Bart, Linda L. Judd and Anne W. Kusterbeck

Abstract: A continuous-flow immunoassay for the plastic explosive hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) was developed using anti-RDX antibodies and a sulfoindocyanine dye-labelled analog of RDX. Anti-RDX antibodies were immobilized onto Emphaze beads (50-80 µm diameter) and 100 µL of the coated beads was transferred to a microcolumn (2 cm x 5 mm i.d.). The column was incorporated into a FIA system consisting of a pump, 100 µL injection loop and a fluorimetric detector. A 100 µL 2.5-5 µM-RDX-dye conjugate in PBS was loaded onto the column and incubated overnight at room temperature to allow the dye-labelled RDX to bind with the immobilized antibody. The column was then washed with a carrier stream (2 ml/min) containing 12% ethanol/0.1% Triton X-100 in PBS to remove unbound dye and produce a stable baseline. Solutions containing RDX (samples or standards) were then injected into the carrier stream. The displacement of the RDX-dye conjugate with RDX was monitored by measuring the change in fluorescence at 663 nm (excitation at 632 nm). The calibration graph for 15-1200 ng/ml RDX is presented. The linear range was 18-300 ng/ml. Fifty analyzes were performed with each column.
Trinitrohexahydrotriazine Immunoassay Fluorescence Sensor

"Analytical Application Of Immobilized Acid Urease For Urea In Flow Streams"
Sens. Actuat. B 1991 Volume 5, Issue 1-4 Pages 241-243
Ikuo Satoh* and Masashi Akahane, Kunio Matsumoto

Abstract: A description is given of a system for the calorimetric flow injection determination of urea (I) which is based on acid urease immobilized on porous glass beads packed into a small polymer column. For determination of I, sample is introduced at 1 mL min-1 via a citrate buffer carrier stream (0.1M; pH 5) and the heat generated by the enzymatic hydrolysis of I is monitored through the enzyme thermistor system. The calibration graph was rectilinear from 0.05 to 2 mM I (1 mL samples). Analysis time was 6 min and the coefficient of variation for 1.0 mM I was 1%. The method may be applied to the determination of I in alcoholic beverages.
Urea Calorimetry Thermistor

"Calorimetric Flow Injection Determination Of Glutathione With Enzyme - Thermistor Detector"
Sens. Actuat. B 1991 Volume 5, Issue 1-4 Pages 245-247
Ikuo Satoh*, Shuji Arakawa and Akira Okamoto

Abstract: For the cited determination glutathione sulfhydryl oxidase and catalase were immobilized separately with bovine serum albumin on Eupergit-C (100 to 200 µm) and double layered into a small polymer column. Sample solution was introduced at 1 mL min-1 via McIlvain buffer (pH 5.0) and the heat generated was measured by the enzyme - thermistor device. The calibration graph was rectilinear from 0.5 to 10 mM glutathione. Analysis time was 6 min and the coefficient of variation for 5.0 mM glutathione was 1.2% (n = 5).
Glutathione Calorimetry Thermistor

"A Critical Comparison Of Different Solid Supports To Develop Room-temperature Phosphorescence Sensing Phases Of Air Moisture"
Sens. Actuat. B 1997 Volume 38, Issue 1-3 Pages 103-109
J. M. Costa-Fern&aacute;ndeza, A. Sanz-Medela,* and M. E. D&iacute;az-Garc&iacute;aa

Abstract: The effects were studied of different solid supports, viz., Dowex 1X2-200 anion-exchange resin beads, Bio-Rex AG 1-X8 anion-exchange membrane, and an inorganic sol-gel matrix, on the detection of moisture in Ar and air based on the quenching effect of water on the room-temperature phosphorescence of the chelate complex formed between 8-hydroxy-7-iodo-5-quinolinesulfonic acid and Al(III). With use of resin beads or anion-exchange membrane as support it was necessary to employ room-temperature phosphorescence lifetime measurements owing to swelling of the support in the wet gas stream. With resin beads and anion-exchange membrane supports the detection limits were 2.1 and 1.4% r.h., respectively, and response was linear up to 100% r.h. For a moisture content of 28.4% r.h. the respective RSD were 2.8% and 4.2% (n = 5). When the chelate was immobilized on a sol-gel prepared by hydrolysis of a mixture of tetramethoxysilane and methyltrimethoxysilane, the limit of detection was 0.09% r.h., and response was linear up to 30% r.h. in the continuous sensing mode, but the analytical range was 0.35-80% r.h. when a flow injection technique was used. At the 8% r.h. level the RSD were 3.2% and 2% respectively (n = 5). Response times were 3-5 min.
Water Environmental Phosphorescence

"Separation And Preconcentration By Flow Injection Coupled To Tungsten-coil Electrothermal Atomic Absorption Spectrometry"
Spectrochim. Acta B 1996 Volume 51, Issue 14 Pages 1925-1934
M&aacute;rcia M. Silva, Francisco J. Krug*, Pedro V. Oliveira, Joaquim A. N&oacute;brega, Boaventura F. Reis and Daniel A. G. Penteado

Abstract: Owing to the uncertain pyrolysis performance of the W-coil atomizer, a flow injection preseparation-pre-concentration system was developed, diagrams of which are presented. A 16 µL SPE microcolumn (Chelex-100) was mounted on the tip of the arm of a Perkin-Elmer GTA-96 ETAAS autosampler, which delivered 20 µL portions of the eluate (eluent 2 M HCl) to the W coil [protected by Ar/H2 (9:1)]. For Pb (model analyte) retained from sample solution flowing at 3 ml/min for 1 min, the enrichment factor was 64, the detection liwas 75 ng/l and the RSD (n = 10) at 2 µg/l was
Lead Spectrophotometry

"Online Sorption Preconcentration And Inductively Coupled Plasma Atomic Emission Spectrometry Determination Of Rare-earth Elements"
Spectrochim. Acta B 1996 Volume 51, Issue 11 Pages 1417-1423
O. N. Grebnevaa, Corresponding Author Contact Information, N. M. Kuz'mina, G. I. Tsysinb and Yu. A. Zolotov

Abstract: The system for online microcolumn sorption pre-concentration and inductively coupled plasma atomic emission spectrometry determination of 14 rare earth elements (REEs) is described. Aminocarboxylic sorbents of different structure are used. Preconcentration of REEs from the 20 mL of sample solution and elution with 210 µl of 1 mol L-1 HCl results in an enrichment factor of 99. The detection limit of REEs is about nx 0.1 µg L-1 (RSD 3-5%). The possibility of simultaneous REE determination in complicated solutions is demonstrated.
Metals, rare earth Geological Spectrophotometry Sample preparation

"Determination Of Manganese At Trace Levels In Natural Waters With Continuous-flow System Utilizing Online Cation-exchange Separation And Catalytic Detection"
Anal. Sci. 1986 Volume 2, Issue 2 Pages 191-195
T. YAMANE

Abstract: The filtered (0.45 µm, Millipore) sample is made ~0.06 M in HCl and passed through a column of Hitachi Custom Resin No. 2611 (15.5 µm; strong cation exchanger), from which Mn is eluted with 0.2 M Na tartrate - 6 mM tartaric acid - 0.32 M NaCl (pH 5.1). Streams of 52 mM 3,4-dihydroxybenzoic acid (I), 1.5% H2O2 solution and 1.0 M Na2CO3 are pre-mixed in a coil, then mixed in a reaction coil (5 m long) with the Mn-containing eluate. The increase in absorbance at 480 nm, due to the Mn-catalyzed oxidation of I, is recorded. The detection limit with use of a 906 µL sample loop is 0.2 ng mL-1. For river and lake waters containing 1.4 to 11.2 ng mL-1 of Mn, the coefficient of variation was <2.5% (n = 5 or 6). The method shows good selectivity.
Manganese Lake River Ion exchange Spectrophotometry

"One-Shot Flow Injection Analysis With Immobilized Enzyme Columns: Clinical Applications"
Anal. Sci. 1987 Volume 3, Issue 3 Pages 277-278
M. OHYABU, M. FUJIMURA, K. TANIMIZU, Y. OKUNO, M. TABATA, M. TOTANI and T. MURACH

Abstract: A flow injection system is described (with diagrams) for the determination of glucose, lactic acid, uric acid and urea-N in serum, plasma or urine. Detection is by chemiluminescence at 425 nm after reaction of enzymatically formed H2O2 with luminol.
Glucose Lactic acid Uric acid Nitrogen, urea Blood Plasma Blood Serum Urine Clinical analysis Chemiluminescence

"Lophine Chemiluminescence For Determination Of Chromium(VI) By Continuous-flow Method"
Anal. Sci. 1989 Volume 5, Issue 4 Pages 429-433
T. KAMIDATE, K. YAMAGUCHI, T. SEGAWA and H. WATANABE

Abstract: Quantitative recovery of Cr(VI) was achieved by passage (10 mL min-1) of the aqueous sample (25 ml) through a column (20 cm x 7 mm) of activated alumina. The column was washed with 0.01 M HNO3 to remove other metal ions, then 0.2 M KOH (10 ml) was used to elute Cr(VI). The eluate was mixed with 0.02 M HNO3 and 0.3 M H2O2 in a continuous-flow analyzer. and the resulting solution was treated with methanolic 1 mM lophine and 0.3 M KOH in a chemiluminescence detection cell. The calibration graph (log. - log. plot) was rectilinear from the detection limit of 0.02 to 30 µg mL-1 of Cr(VI). The method was used to determine Cr(VI) in water.
Chromium(VI) Environmental Chemiluminescence

"Flow Injection Method For The Separation Of Thallium And Gold On A Sephadex Column And Their Extraction-photometric Determination With Rhodamine B"
Anal. Sci. 1990 Volume 6, Issue 3 Pages 421-424
H. KOSHIMA and H. ONISHI

Abstract: The method involves injection of a sample into 0.5 M HCl - 1 M LiCl as carrier solution (0.6 mL min-1), and passsage through a column (15 cm x 3 mm) of Sephadex G-25. The eluate is added to 0.04% rhodamine B (0.18 mL min-1), and the mixture is then mixed with benzene (0.2 mL min-1). After passage through a 2-m extraction coil and a phase separator, the absorbance of the organic phase is measured at 565 nm. The retention times for Tl and Au on the column are 5.5 and 11 min, respectively. From 0 to 5 mg L-1 of each metal can be determined. The method was applied to coal fly ash and ores. Recoveries were 97 to 98% for Tl and Au in the respective samples.
Thallium Gold Coal Fly ash Geological NIST 1633 Spectrophotometry Sample preparation

"High Performance Liquid Chromatographic Determination Of Ribonucleotides By Post-column Derivatization Involving Oxidation Followed By Fluorescence Reaction And Its Application To Human Erythrocyte Samples"
Anal. Sci. 1990 Volume 6, Issue 4 Pages 519-522
Y. UMEGAE, H. NOHTA and Y. OHKURA

Abstract: Ribonucleotides such as ATP and ADP were separated on a column (25 cm x 4.6 mm) of TSK gel ODS-80 (5 µm) and converted into fluorescent derivatives by reaction with 1,2-bis-(4-methoxyphenyl)ethylenediamine in acidic medium after oxidation with NaIO4. The detection limits were 14 to 67 pmol injected. The method was applied to human erythrocytes, and showed good sensitivity and high selectivity.
Ribonucleotides Human HPLC Fluorescence

"Potentiometric Determination Of Reducing Sugars As Borate Complexes Using Hexacyanoferrate(III) - Hexacyanoferrate(II) Potential Buffer And Its Application To Liquid Chromatography"
Anal. Sci. 1990 Volume 6, Issue 5 Pages 777-779
H. OHURA, T. IMATO, S. YAMASAKI and N. ISHIBASHI

Abstract: A system of flow injection analysis with HPLC (diagram given) for the determination of mixed reducing sugars (mono- and di-saccharides) was described with use of a flow-through type oxidation-reduction potential electrode detector cell and a potentiometer. A potential buffer solution comprising 0.1 M [Fe(CN)6]3- - 0.1 M [Fe(CN)6]4- and containing 1 M NaOH was pumped at 0.45 mL min-1 and the 0.5 M borate reagent solution was pumped at 0.5 mL min-1. Sample solution (20 µL) was injected into the borate stream and carried through an anion-exchange column (15 cm x 4.6 mm) of TSK-Gel, Sugar AXI, TOSO for separation at 60°C. The column effluent was merged with the potential buffer solution and the composition change of the buffer caused by reduction of [Fe(CN)6]3- was measured. The calibration graph was almost rectilinear for 2.5 to 10 µM of the mixed saccharides. The coefficient of variation was 1.5% (n = 5) for a 10 µM mixture of cellobiose, maltose and lactose. Detection limits were 0.4 to 2 µM. Sensitivity was similar to or better than amperometric, fluorimetric and spectrophotometric detection methods.
Sugars, reducing Potentiometry HPLC Electrode Ion exchange

"Determination Of The Sulfate Ion Concentration In Rain Water By Flow Injection Analysis Incorporated With A Barium Chloranilate Reaction Column"
Anal. Sci. 1990 Volume 6, Issue 5 Pages 711-714
K. YAKATA, F. SAGARA, I. YOSHIDA and K. UENO

Abstract: Rain water, diluted 1:1 with ethanol, was injected into a carrier solution of aqueous 0.5% NH4Cl - ethanol (1:1; 1.9 mL min-1) and passed through a cation-exchange column (5 cm x 4.6 mm) of Muromac 50W-X 4 (100 to 200 mesh; NH4+ form) and a reaction column (same dimensions) of Ba chloranilate powder (120 mesh). The absorbance of the eluate was monitored at 530 nm. The calibration graph was rectilinear for 4 to 100 ppm of SO42-. Sample throughput was 1 min-1. The results agreed well with those obtained by the standard manual method.
Sulfate Rain Ion exchange

"Determination Of Seven Opioid Peptides In Rat Brain By High Performance Liquid Chromatography With Online Post-column Fluorescence Derivatization"
Anal. Sci. 1990 Volume 6, Issue 5 Pages 671-676
G.-Q. ZHANG, M. KAI and Y. OHKURA

Abstract: Sample solution (prep. described; 60 µL) was incubated with 10 µL of carboxypeptidase A or trypsin in 50 mM phosphate buffer (pH 7.8) and phosphate buffer (40 µL) for 30 min at 37°C. A 100 µL portion was analyzed by HPLC on a column (15 cm x 6 mm) of Asahipak ODP-50 (5 µm) with gradient elution (1 mL min-1) with acetonitrile - 50 mM sodium borate buffer (pH 10.0) - water (1:4:15 and 3:1:1). The column eluate was mixed with 0.3 M borate buffer (pH 8.5) and 8 mM hydroxylamine oxalate - 0.2 mM Co(II) acetate, the mixture was passed through a reaction coil (10 m x 0.5 mm) heated to 100°C, and the fluorescence was monitored at 430 nm (excitation at 330 nm). The method was used for the simultaneous determination of seven endogenous opioid peptides at the pmol level in brain tissue. Detection limits were 0.5 to 1.5 pmol injected.
Peptides Brain HPLC Fluorescence

"High Performance Liquid Chromatographic Determination Of Acidic Catecholamine Metabolites In Human Urine Using Post-column Fluorescence Derivatization With Dl-1,2-diphenylethylenediamine"
Anal. Sci. 1990 Volume 6, Issue 5 Pages 677-682
H.-K. JEON, H. NOHTA and Y. OHKURA

Abstract: Urine was diluted 5-fold with water, ultra-filtrated, and 3,4-dihydroxymethoxymandelic acid, 4-hydroxy-3-methoxy- and 3,4-dihydroxy-phenylacetic acid and 4-hydroxy-3-methoxymandelic acid were determined by HPLC on a column (25 cm x 4.6 mm) of TSK gel DEAE-2SW anion-exchange gel (5 µm) with 25 mM NaH2PO4 (pH 3.0) - 70 µM-Na2EDTA containing 30% of acetonitrile as mobile phase (1 mL min-1) and electrochemical detection at 0.5 V vs. Ag - AgCl. The eluate was mixed with 40 mM dl-1,2-diphenylethylenediamine in propan-2-ol and 50 mM Na methoxide in propan-2-ol (0.4 mL min-1), the mixture was passed through a reaction coil (10 m x 0.5 mm) at 110°C. After cooling the fluorescence was monitored at 515 nm (excitation at 420 nm). The detection limits were 15 to 20 fmol. The method was 20-times more sensitive to 3,4-dihydroxymandelic acid than methods using meso-1,2-diphenylethylenediamine and did not require complicated sample cleanup.
Catecholamines Urine HPLC Fluorescence

"Determination Of Selenium By Flow-injection Analysis Based On The Selenium(IV)-catalyzed Reduction Of 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium Bromide"
Anal. Sci. 1991 Volume 7, Issue 1 Pages 103-107
E. AOYAMA, N. KOBAYASHI, M. SHIBATA, T. NAKAGAWA and H. TANAKA

Abstract: Sample solution was mixed with NaOH (to pH 7) and 0.1 M phosphate buffer solution (pH 7) containing 12 mM bathocuproine disulfate and the mixture was injected into a carrier solution of 0.1 M phosphate buffer solution (0.2 mL min-1) and through a column (5 cm x 4.6 mm) of Chemcasorb 3-ODS-H operated at 40°C. The eluate was mixed with 7.3 mM dithiothreitol and 3-[4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide and the absorbance of the solution was measured at 565 nm. Analysis time was 8 min. The calibration graph was rectilinear for 1.3 pmol to 1.2 nmol Se (IV) and the coefficient of variation was 2.2%. The method was applied in the analysis of lobster refrence material, recovery was 103% for 5 µg mL-1 of Se and no interference was present.
Selenium NRCC TORT-1 Spectrophotometry

"Simultaneous Determination Of Catecholamine-related Compounds By High Performance Liquid Chromatography With Post-column Chemical Oxidation Followed By A Fluorescence Reaction"
Anal. Sci. 1991 Volume 7, Issue 2 Pages 257-262
H. -K. JEON, H. NOHTA, H. NAGAOKA and Y. OHKURA

Abstract: Thirteen such compounds (three catecholamines, one precursor and nine metabolites), together with isoprenaline and 3-(3,4-dihydroxyphenyl)propionic acid, were separated on a TSK-gel ODS-80TM column (25 cm x 4.6 mm) with methanol - 0.4 mM Na octane-1-sulfonate in 30 mM citrate buffer (7:93) as mobile phase (0.8 mL min-1). The separated components were oxidized to the corresponding o-quinones by treatment with 10 mM NaIO4 - 3 mM K3Fe(CN)6, and these were converted into fluroescent derivatives by reaction with 30 mM meso-1,2-diphenylethylenediamine in aqueous 70% ethanol solution containing 0.13 M Na methoxide. The fluorescence intensity was monitored continuously at 480 nm (excitation at 350 nm). Detection limits ranged from 14 fmol for adrenaline to 570 fmol for (4-hydroxy-3-methoxyphenyl)ethanediol, and coefficient of variation were ~3.1% (n = 10).
Catecholamine, derivatives HPLC Fluorescence

"Chemiluminescence Determination Of Titanium(IV) By Flow Injection Analysis Using A Jones Reductor Column Online"
Anal. Sci. 1991 Volume 7, Issue 4 Pages 623-625
A. A. ALWARTHAN, A. ALMUAIBED and A. TOWNSHEND

Abstract: The cited determination involves the reaction of Ti(III) with a carbonate buffer after passing the Ti(IV) samples through a Jones reductor mini-column using 0.01 M HCl as a carrier stream. The detection limit was 1 µM. The coefficient of variation of 40 mM Ti was 4.4%. The Ti signal was affected by Ni(II), Co(II), Cd(II), Ce(IV) and Mo(VI).
Titanium(IV) Chemiluminescence

"Flow Injection Analysis With Online Preconcentration Of Trace Selenium"
Anal. Sci. 1991 Volume 7, Issue 4 Pages 617-621
E. AOYAMA, K. AKAMATSU, T. NAKAGAWA and H. TANAKA

Abstract: The cited system (details given) was developed for determining very low concentration. of Se(IV). The Se was selectively collected as selenotrisulfide on a micro-column (5 cm x 1 mm) packed with resin loaded with Bismuthiol-II sulfonate and eluted with aqueous penicillamine solution The resulting penicillamine selenotrisulfide was introduced into the flow injection analyzer. (details given); detection was at 565 nm. Interference from Cu ion was eliminated by adsorption of Cu on the resin as bathocuproine disulfonate chelate. Determination of Se in a standard biological sample, e.g., lobster was used to confirm the reliability of the method.
Selenium Biological Spectrophotometry

"Determination Of Nickel, Cobalt, Copper, Thorium And Uranium In High-purity Zinc Metal By ICP-MS With Online Matrix Separation"
Anal. Sci. 1995 Volume 11, Issue 1 Pages 13-16
M. FUKUDA, Y. HAYASHIBE and Y. SAYAMA

Abstract: Zn metal (5 g) was dissolved in 9 M HCl and evaporated almost to dryness. The residue was dissolved in 50 mL 2 M HCl and a 170 µL portion was injected into a stream of 2 M HCl at 0.4 ml/min. The carrier stream flows through a BIORAD AG1-X8 anion-exchange column (3 cm x 2 mm i.d.) where the matrix Zn was absorbed and the analytes passed directly into the ICP-MS. After 700 s of sample injection the zinc matrix was flushed from the column with 2 M HNO3 at a flow rate of 3 ml/min. The column was regenerated by washing with 2 M HCl at 0.4 ml/min for 300 s. The calibration graphs were linear up to 10 ng/ml for each analyte. The detection limits were 0.12, 0.48, 1.2, 3.1 and 4 ng/g, respectively, for Th, U, Co, Ni and Cu. RSD (n = 3) were 5% at 10 ng/ml. The method was applied to the analysis of high-purity zinc metals and three NIST standard reference zinc standards. Recoveries were 95-116%.
Cobalt Copper Nickel Thorium-232 Uranium High purity NIST 682 Ion exchange Mass spectrometry

"Simultaneous Flow Injection Determination Of Acetylcholine And Choline Based On Luminol Chemiluminescence In A Micellar System With Online Dialysis"
Anal. Sci. 1997 Volume 13, Issue 1 Pages 93-98
T. HASEBE, J. NAGAO and T. KAWASHIMA

Abstract: The method was based on the determination of H2O2 produced from acetylcholine (I) and choline (II) by enzyme reactions. A flow diagram is given of the FIA system. A water carrier, a 0.02 M disodium hydrogen phosphate/NaOH buffer of pH 11, a 0.02 M phosphate buffer of pH 7, a 1 µM-Co(II) solution in 0.01 M HCl as a catalyst for the chemiluminescence reaction and a mixed solution of 0.5 µM-luminol, 0.1 M sodium hydrogen carbonate and 0.18% SDS in borate buffer solution of pH 11 were pumped by three double-plunger pumps. An 800 µL sample was injected into the carrier, dialysed to remove protein and passed through an anion-exchange column to remove other interferents such as ascorbic acid, uric acid, histidine and tryptophan. II was converted to H2O2 via choline at another immobilized enzyme column. H2O2 produced from II was passed through a delay coil before the chemiluminescence of I and II were measured from 350-650 nm. The reactions were performed at 37°C. The method could determine down to 1 µM at a sampling rate of 6 samples/h.
Acetylcholine Choline Chemiluminescence

"Online Preconcentration Of Rare-earth Element By FIA-ICP-AES"
Anal. Sci. 1997 Volume 13, Issue suppl Pages 27-30
GAE HO LEE, SOON A. PARK, KYUSEOK SONG, HYUNGKI CHA, JONGMIN LEE, and SANG CHUN LEE

Abstract: A mini-column filled with Dowex 50x8 resin is developed and investigated for the analysis of trace level of rare earth element by ICP-AES. The column is installed between peristaltic pump and ICP-AES, and ng/ml level of rare earth element is analyzed directly by online FTA-ICP-AES. 6N hydrochloric acid is found to be an optimum concentration for stripping, and the optimum flow rates for loading and stripping are measured at 0.8 and 1.1 ml./min, respectively. Easily ionized elements from flux such as Na and K would be eliminated easily by 2N hydrochloric acid before stripping the rare earth element deposited on the resin. For an analysis of Sm, the absolute detection limit and linearity are found to be than 4% of reproducibility is observed for the analysis of Sm and Nd. The analytical result with NIST SRM 1633B is also found to be 20.3 ng/ml, which agrees well with tile certified value. 9 References
Metals, rare earth Samarium Neodymium NIST 1633 Coal Fly ash Spectrophotometry

"A Flow Injection System For Spectrophotometric Catalytic Determination Of Copper In Plant Digests And Natural Waters"
Anal. Sci. 1998 Volume 14, Issue 3 Pages 565-569
Fabiana C. CAMARGO), Elias A. G. ZAGATTO) and Claudio C. OLIVEIRA

Abstract: The Cu(II)-catalyzed oxidation of 2,6-dichlorophenolindophenol (DCPI) in the reduced form by hydrogen peroxide was exploited for the development of a flow injection procedure for Cu determination in plant digests and natural waters. For selectivity enhancement, a Chelex-100 resin mini-column (50 - 100 mesh) was incorporated to the manifold. The proposed system is very stable, handles about 60 samples/h, yields precise results (RSD<2% within 5.0 and 70.0 µg/L Cu) and requires only 0.87 mg DCPI/measurement. Beer's law is followed up to about 100 µg/L Cu and the detection limit is 0.09 µg/L Cu (in the injectate). Baseline drift was not observed during extended (5 h) operation periods. Results were in agreement with certified values of standard reference materials and recoveries within 95 and 104% were found.
Copper Environmental Plant Spectrophotometry

"Safety In Numbers: Detection With Voltammetric Arrays"
Anal. Proc. 1989 Volume 26, Issue 11 Pages 389-390
T. H. Brearley, A. K. Doshi and P. R. Fielden

Abstract: Details are given of a potentiostatic system comprising a wall-jet array of working electrodes, each with its potential independently controlled. A central vitreous-carbon electrode (diameter 3 mm) surrounded by eight satellite electrodes (diameter 1 mm), on to which the sample flow impinges, is accommodated in one half of a flow cell; the other half contains an inlet jet and the Ag - AgCl reference and Pt disc counter electrodes. The operation of the array is demonstrated by the detection of Fe(II) fumarate in a flow injection system with 0.1 M HCl as carrier, and by its use as detector in the HPLC of substituted phenols on a C18 column with aqueous 55% methanol containing KCl and H2SO4 as mobile phase. The array performed reliably, and for the phenols provided appropriate qualitative information.
Voltammetry HPLC

"Determination Of Selenium In Copper Metal Using Flow Injection Hydride-generation Atomic Absorption Spectrometry With Continuous-flow Matrix Isolation"
Anal. Proc. 1991 Volume 28, Issue 1 Pages 18-20
Stephen G. Offley, Nichola J. Seare, Julian F. Tyson and Helen A. B. Kibble

Abstract: Selenium could be determined in copper sample solution by hydride-generation AAS, after removal of Cu by passage through a micro-column of Dowex 50W-X8 (H+ form). Optimum flow rate was 2 mL min-1 and optimum pH was ~2.0. The system and method of analysis are described in detail. Results for two reference samples agreed with certified values. The limit of detection was 2.1 ng mL-1 of Se, the coefficient of variation was 1.5% (n = 12) at 10 ng mL-1, and the sample throughput was 17 h-1.
Selenium Metal Spectrophotometry

"Field Sampling Technique For Mercury Speciation"
Anal. Proc. 1991 Volume 28, Issue 9 Pages 293-294
Wei Jian, C. W. McLeod

Abstract: Water (2 to 10 ml) was adjusted to pH 3 to 4 with concentrated HCl and passed through a micro-column (5 cm x 1.5 mm) of sulfydryl cotton. The column was inserted into a flow injection atomic fluorescence spectrometry system (illustrated). The analytical procedure consisted of injection of 0.5 mL of 3 M HCl to elute the retained organomercury species which were then converted into inorganic Hg species by a bromide - bromate reagent. The inorganic Hg was merged with tin chloride before detection by cold vapor AFS.
Mercury Fluorescence Spectrophotometry

"Online Preconcentration And Determination Of Lead By Fibrous Alumina And Flow Injection - Atomic Absorption Spectrometry"
Anal. Proc. 1994 Volume 31, Issue 2 Pages 61-63
Shayessteh Dadfarnia, Ian Green and Cameron W. McLeod

Abstract: Water was acidified to pH 2 with HNO3 and left to stand overnight. After adjustment to pH 8 with NH3 solution, the sample was passed at 4.5 ml/min through a PTFE micro-column (4 cm x 1.5 mm i.d.) of fibrous alumina, previously made basic with 0.1 M NH4OH (carrier stream). Elution was effected at 4.5 ml/min with 1 M HNO3 and the eluate was transported to an air-acetylene flame for AAS analysis with measurement at 283.3 nm. The calibration graph was linear for 2.5-100 µg/l of Pb; the detection limit was 0.7 µg/l. The RSD (n = 7) for 2 and 5 µg/l of Pb were 2.3 and 4.9%.
Lead Water Spectrophotometry

"Determination Of Sulfite In White Wine By Amperometric Flow Injection Analysis With An Immobilized Sulfite Oxidase Reactor"
Agric. Biol. Chem. 1989 Volume 53, Issue 9 Pages 2347-2353
Kiyoshi MATSUMOTO, Hiroaki MATSUBARA, Hiroyuki UKEDA and Yutaka OSAJIMA

Abstract: Sample (4 ml) is mixed with 2.5% gelatin solution (1 ml) to remove interfering substances (e.g., polyphenols), filtered, and diluted ~20-fold with 0.1 M phosphate buffer of pH 8.0, and portions (240 µL) are passed in parallel through a column (10 cm x 2 mm) of sulfite oxidase immobilized on CNBr-activated Sepharose 4B and a blank column of Sepharose without the enzyme. The mobile phase is the 0.1 M phosphate buffer, and detection is by amperometry at +0.50 V in a flow-through cell fitted with a Pt-wire working electrode, a vitreous-carbon counter electrode and a reference Ag - AgCl (KCl) electrode. The difference in response for the streams with and without enzyme treatment is used to calculate the SO32- content. Typically, the calibration graph was rectilinear for 1 to 10 ppm of SO32-, the recovery was 94%, and the coefficient of variation at 5 ppm was 2.3% (n = 10). Response was maintained for 20 days and fell to 67% of the original value after 45 days for 5 ppm of SO32-. Results for red wine were erratic, showing that the gelatin treatment does not wholly prevent interference.
Sulfite Wine White Wine Red Amperometry Electrode

"Co-immobilization Of Alcohol Dehydrogenase, Diaphorase And NAD+ And Its Application To Flow Injection Analytical System For Ethanol"
Agric. Biol. Chem. 1989 Volume 53, Issue 11 Pages 2909-2915
Hiroyuki UKEDA, Masatomo IMABAYASHI, Kiyoshi MATSUMOTO and Yutaka OSAJIMA

Abstract: Sepharose activated with CNBr was repeatedly modified with hexamethylenediamine and glutaraldehyde as spacers before use for immobilization of the cited enzymes and NAD+ at 20°C during 7 h from 0.05 M phosphate buffer of pH 8.0 (buffer A). A column of the product was used in a flow injection system for the determination of ethanol, the O consumption being measured amperometrically with a Clark O electrode maintained at -0.8 V in a flow-through cell; buffer A was used as carrier. Response was rectilinearly related to ethanol concentration. from 20 to 80 mM. The response fell markedly during the first three injections of 20 mM ethanol, but then decreased more slowly; the response after 19 injections was 70% of that after the third.
Ethanol Amperometry Electrode

"Immobilized Catalyst For Detecting Chemiluminescence In Lipid Hydroperoxide"
Agric. Biol. Chem. 1991 Volume 55, Issue 5 Pages 1217-1223
Akira WADANO, Teturo IKEDA, Motonobu MATUMOTO and Michio HIMENO

Abstract: A study was conducted to determine whether catalysts could be immobilized on a gel for HPLC without losing their activity. Microperoxidase and cytochrome c were immobilized on Affi-prep 10, Epoxy-Toyopearl, Formyl-Toyopearl and Tresyl-Toyopearl. Chemiluminescence was detected with a Wako Pure Chemical Industries instrument. A stainless-steel column (10 cm x 4 mm) was packed with the immobilized enzyme and used with methanol - CHCl3 (9:1) as the carrier stream in a flow injection system. The reagent solution contained 1 µg mL-1 of isoluminol or luminol in 50 mM borate buffer. The specificity of each immobilized catalyst was compared with that of the free form.
Hydroperoxides, lipid Chemiluminescence HPLC

"Voltammetric Determination Of The Herbicides Thiram And Disulfiram With A Cobalt Phtalocyanine Modified Carbon-paste Electrode"
Analusis 1995 Volume 23, Issue 7 Pages 319-324
FERNANDEZ C. ; REVIEJO A. J. ; PINGARRON J. M.

Abstract: The voltammetric behavior of two dithiocarbamic acid derivative herbicides, thiram and disulfiram, at a carbon paste electrode modified with the electron mediator cobalt phthalocyanine is described. Cyclic voltammograms showed a decrease of the overpotential of around 100 mV for the electrochemical oxidation of the herbicides, as well as a remarkable increase in the peak current, using the modified electrode with respect to the plain carbon paste electrode. The appropriate CoPC percentage in the carbon paste and the working medium used as background electrolyte were optimized by differential pulse voltammetry. Both thiram and disulfiram showed enhanced oxidation signals when open-circuit accumulation in stirred solutions was carried out, and, consequently, the adsorption process can be used as an effective pre-concentration step. The dependence of peak current on accumulation time was studied. Using differential pulse voltammetry in the stripping step, limits of detection of 7.1 x 10^-8 and 2.2 x 10^-8 mol L-1 were obtained for thiram and disulfiram, respectively. The effect of the presence of the herbicide ziram, phenol, and Zn(II) on the oxidation signals for thiram and disulfiram was evaluated. The developed using the catalytic-adsorptive processes of the herbicides at the CoPC modified electrode was applied to the determination of thiram in samples of spiked strawberries. Finally, the capabilities of the modified electrode as an amperometric indicator electrode for flow injection analysis with pulsed amperometric detection were considered. (19 References)
Disulfiram Thiram Fruit Electrode Voltammetry

"Use Of Zirconia Microcolumn For Online Preconcentration In Flow Injection ICP Atomic Emission Spectrometry"
Beijing Gongye Daxue Xuebao 1990 Volume 16, Issue 2 Pages 36-38
Li Tichnan C W Mcleod

Abstract: A zirconia micro-column was used for the pre-concentration. of bi- and tervalent elements in flow injection ICP-AES. The pre-concentration. factor for 50 µg L-1 of Cd was 40. The capacities for the elements studied were 28 to 56 µg g-1.
Spectrophotometry

"A Chemiluminometric Method For NADPH And NADH Using A Two-enzyme Bioreactor And Its Application To The Determination Of Magnesium In Serum"
Biomed. Chromatogr. 1990 Volume 4, Issue 3 Pages 123-127
Masayoshi Tabata, Masayuki Totani, Takashi Murachi

Abstract: Chemiluminometric methods are described for the automated flow injection analysis of NADPH and NADH using an immobilized enzyme column reactor and serum magnesium. This application is for the clinical analysis of NADPH and NADH. The reactor for NADPH and NADH contains immobilized L-glutamate dehydrogenase and L-glutamate oxidase, and that for serum magnesium immobilized hexokinase, glucose-6-phosphate dehydrogenase, L-glutamate dehydrogenase and L-glutamate oxidase. Whtained from standard solutions and 0.5% from complex samples (at 1000 mg/L).
Magnesium Nicotinamide adenine dinucleotide oxidized Nicotinamide adenine dinucleotide phosphate oxidized Blood Serum Chemiluminescence Clinical analysis

"Evaluation Of Pyrimido[5,4-d]pyrimidine Derivatives As Peroxyoxalate Chemiluminescence Reagents Using A Flow Injection System"
Biomed. Chromatogr. 1990 Volume 4, Issue 3 Pages 105-107
Kenichiro Nakashima, Kouichi Maki, Shuzo Akiyama, Kazuhiro Imai

Abstract: Eighteen kinds of pyrimido[5,4-d]pyrimidines together with several commercially available fluorescent compounds such as perylene, Rhodamine B, etc., were evaluated as the reagents for a peroxyoxalate chemiluminescence (CL) detection system by using a flow injection method. The peroxyoxalate CL reaction employed consists of bis(2,4,6-trichlorophenyl)oxalate, hydrogen peroxide, triethylamine, and a fluorophore. Under the conditions used, 2,6-bis[di-(2-hydroxyethyl)amino]-4,8- dipiperidinopyrimido[5,4-d]pyrimidine (Dipyridamole) and 2,4,6,8-tetrathiomorpholinopyrimido[5,4-d]pyrimidine (1i) gave very intense chemiluminescence intensities which were larger than those of any other commercially available fluorescent compounds tested (e.g., 10 times larger than that of perylene). Derivatives of pyrimido[5,4-d]pyrimidine in CHCl3 or methanol were injected into a stream of 3 mM triethylamine in acetonitrile (1.0 mL min-1), which was combined with a stream of 0.15 mM bis(2,4,6-trichlorophenyl)oxalate and 4.5 mM H2O2 in acetonitrile (1.0 mL min-1) and the intensity of the chemiluminescence generated was measured. Standard curves were prepared with use of known concentration. of each fluorescent compound. Results are tabulated for 17 compounds. Very intense chemiluminescence was observed with use of dipyridamole and 2,4,6,8-tetrathiomorpholinopyrimido[5,4-d]pyrimidine.
Pyrimidines, pyrimido[5-4-d] Chemiluminescence

"A New Method For The High Performance Liquid Chromatographic Determination Of TA-870, A Dopamine Prodrug"
Biomed. Chromatogr. 1990 Volume 4, Issue 5 Pages 181-187
Masayoshi Yoshikawa, Hiroshi Endo, Kumiko Hoshino, Yoichi Sugawara, Osasi Takaiti, Susumu Kanda, Kazuhiro Imai

Abstract: A new method for the high performance liquid chromatographic (HPLC) determination of N-(N-acetyl-L-methionyl)-O,O-bis(et hoxycarbonyl)dopamine (TA-870), a dopamine prodrug, in biological fluid has been developed. In order to measure with an electrochemical detector (ECD), TA-870 was passed first through an immobilized carboxylesterase column to be converted to the electrochemically active deethoxycarbonylated TA-870 (DEC-TA-870). The properties of this carboxylesterase immobilized on Sepharose 4B were examined by this flow injection system. Hydrolysis of TA-870 with this immobilized carboxylesterase was a maximum at pH 7-8 and 50°C, and the activity decreased in the presence of organic solvent such as acetonitrile. For the determination of TA-870 in biological fluids, an HPLC-immobilized enzyme-ECD system using a column-switching technique was developed. The blood was deproteinized with ethanol, and TA-870 in the ethanol extracts was adsorbed in Bond Elut C18. The dichloromethane eluate from Bond Elut C18 was injected into the HPLC system. The HPLC apparatus was composed of three pumps, two separation columns (LiChrosorb Si 60 and µBondasphere), a trap column (Bond Elut), an enzyme column, ECD and the column-switching system. The calibration curve for TA-870 in blood was linear in the range from 2 to 200 ng/mL. This new assay method might be useful also for the determination of other catechol ester compounds.
Drugs N-(N-acetyl-L-methionyl)-O,O-bis(ethoxycarbonyl)dopamine Blood HPLC

"Flow Injection Glucose Determination With Long-wavelength Luminescent Oxygen Probes"
Biomed. Sci. 1991 Volume 2, Issue 1 Pages 63-67
Papkovskii DB, Savitskii AP, Yaropolov AI, Ponomarev GV, Rumyantseva VD, Mironov AF.

Abstract: A flow injection method for the determination of glucose in serum is presented. It is based on the enzymatic measurement of oxygen consumption detected via oxygen quenching of the luminescence of certain metalloporphyrins. Phosphorescent water-soluble Pt2+ and Pd(2+)-porphyrins have been characterized by luminescence spectroscopy and decay-time measurements in various buffers, and found to be suitable for oxygen detection in biological systems. A new method for the flow injection analysis of glucose has been developed based on the use of a column of immobilized glucose oxidase and the indicators Pt(2+)-coproporphyrin III and Pd(2+)-coproporphyrin I. The system has been optimized for glucose determination in aqueous samples and in whole serum with the 0.5-200 mM glucose range. Twenty assays can be performed in an hour, and the system has potential for commercial development with biotechnological and medical applications.
Glucose Blood Serum Biotechnology Luminescence Phosphorescence

"Endogenous Plasma N-acetylcysteine And Single Dose Oral Bioavailability From Two Different Formulations As Determined By A New Analytical Method"
Biopharm. Drug Dispos. 1991 Volume 12, Issue 5 Pages 343-353
Bernard Gabard, Hermann Mascher

Abstract: Plasma (0.5 ml) was mixed with 0.5 mL of water and 30 µL of 10% tributyl phosphine in methanol. After 30 min at 37°C, 0.15 mL of 20% HClO4 was added and the solution was centrifuged at 2500 g. A portion (100 muwl) of the supernatant solution was analyzed by HPLC on a column (8 cm x 4 mm) of Nucleosil 120 C18 (3 µm) with ethanol - 0.1 M H3PO4 - triethylamine (40:960:1), containing glycine at 100 µg mL-1, as mobile phase (1 mL min-1). The column eluate was mixed with 0.5 M NaOH - 0.1 M H3BO3 (41:59), containing o-phthalaldehyde (10 µg mL-1), at 1 mL min-1 in a reaction tube (described) and detected at 475 nm (excitation at 325 nm). The calibration graph was rectilinear from 0.06 to 8 µM-acetylcysteine; the detection limit was 6 nM. The coefficient of variation (n = 3) were 4.4% at 60 nM and 0.1% at 8 µm. The method is specific for thiols, e.g., cysteine, glutathione, thioglycolic acid and homocysteine.
Cysteine Glutathione Homocysteine Thioglycolic acid Thiols Blood Plasma HPLC Fluorescence

"Determination Of Aspartame In Dietary Food Products By A FIA Biosensor"
Biosens. Bioelectron. 1991 Volume 6, Issue 2 Pages 117-123
K. B. Male, J. H. T. Luong* and A. Mulchandani

Abstract: A flow injection analysis (FIA) biosensor system was developed for the determination of the artificial sweetener aspartame (N-L-α-aspartyl-L-phenylalanine methyl ester). The system consisted of two enzyme columns, containing purified peptidase and aspartate aminotransferase respectively, immobilized on activated aminopropyl glass beads and an enzyme electrode connected in series. The dipeptide bond of aspartame was cleaved by immobilized peptidase to release aspartic acid which was in turn transaminated by aspartate aminotransferase. The glutamate produced by transamination was monitored by the enzyme electrode which used L-glutamate oxidase immobilized on a nylon membrane in combination with a hydrogen peroxide electrode. The response of the FIA biosensor was linear up to 1 mM aspartame with a lower detection limit of 20 micromole and had good reproducibility (RSD2.2%). The FIA biosensor was stable for at least 30 h of continuous use at room temperature and the immobilized enzymes were stable for at least 1 month when stored in buffer at 4°C. Each assay takes ~7-8 min giving a sample through put of 8 h-1. When applied to aspartame measurements in dietary food products, the results obtained agreed well with those reported by the product manufacturer. The flow injection analysis system described contains two enzyme columns, containing purified peptidase and aspartate aminotransferase, respectively, immobilized on activated aminopropyl glass beads, and an enzyme electrode of L-glutamate oxidase immobilized on a nylon membrane in combination with a H2O2 electrode. The immobilization of the enzymes and the purification of the aspartame peptide-bond-cleaving enzyme are detailed. The effects of pH, flow rate, α-ketoglutarate and column length on the flow injection analysis response were measured. The calibration graph was rectilinear up to 1 mM aspartame, with a detection limit of 20 µM and a coefficient of variation (n=8) of 2.2%. The biosensor was stable for at least 30 h of continuous use at room temperature and the immobilized enzymes were stable for at least 1 month when stored in buffer at 4°C. Each assay takes 7-8 min. The method was applied to dietary food products.
Aspartame Food Electrode Sensor

"Flow-through Enzyme Analyser For Determination Of L-lysine Concentration"
Biosens. Bioelectron. 1991 Volume 6, Issue 2 Pages 93-99
A. L. Simonian, G. E. Khachatrian, S. Sh. Tatikian, Ts. M. Avakian and I. E. Badalian

Abstract: The flow-through analyzer was based on an oxygen electrode and L-lysine-2-monooxygenase immobilized on silica gel. A schematic diagram is given of the analyzer. and a cross-section of the measurement cell shows a special construction allowing the buffer and its waste to be placed proportionally under the O electrode. The buffer solution was pumped through a pulse damper into the column containing immobilized enzyme. The sample was dosed by a device which injected 70 µL of sample into the column without interruption of the buffer flow. Oxygen concentration. was measured by means of a Clark membrane electrode (0.5 M KCl solution as the electrolyte, Pt cathode and Ag anode, pulse height -0.65 V). Calibration graphs were rectilinear from 5.5 to 55 mM (1 to 10 g l-1) of L-lysine I at pH 8.2. The analyzer. showed high specificity for I. The response time was 15-30 s, with a total analysis time about 3 min. The immobilized enzyme retained at least 50% of its activity for 2 months. Measurement have been made in the fermentation broth of fermenters and in fodder L-lysine concentrate. The analyzer. can be used autonomously and also with a microcomputer or microprocessor.
l-Lysine Fermentation broth Electrode

"Evaluation Of Polypyrrole - Glucose Oxidase Electrodes In Flow Injection Systems For Sucrose Determination"
Biosens. Bioelectron. 1991 Volume 6, Issue 3 Pages 263-273
Wolfgang Schuhmann and Ruth Kittsteiner-Eberle

Abstract: Thin films of polypyrrole were deposited on Pt or vitreous-carbon disc electrodes (1 or 3 mm diameter) by electropolymerization of the monomer. The polymer film was nitrated by treatment with acetic anhydride and Cu(NO3)2 and the nitro-groups were reduced electrochemically to amino-groups. The glucose oxidase was immobilized on the electrode surface via the formation of amides or secondary amines (full details given). The electrodes were operated at a working potential of +600 mV (vs. the SCE), and in the flow injection mode, with 0.5 M NaCl - 0.1 M phosphate (pH 7.4) as supporting electrolyte, responses were rapid (~10 s) and rectilinear for 0.05 to 10 mM glucose. The response fell to 60 to 80% of its initial value after 2 days, but then remained fairly constant for a further 20 to 23 days. Attempts to determine simultaneously glucose and sucrose in the same solution, by use of two electrochemical sensors, in combination with immobilized β-fructofuranosidase (I) and aldose 1-epimerase (II), were unsuccessful owing to inhibition of glucose oxidase by the relatively high concentration. of sucrose. However simultaneous determination of glucose and sucrose was possible in a flow injection system containing enzyme columns with glucose dehydrogenase, I and II immobilized on controlled-pore glass, with fluorimetric determination of enzymatically generated NADH.
Glucose Sucrose Electrochemical analysis Electrode Electrode Electrode Electrode Fluorescence

"An Apoenzyme Thermistor Microanalysis For Zinc(II) Ions With Use Of An Immobilized Alkaline Phosphatase Reactor In A Flow System"
Biosens. Bioelectron. 1991 Volume 6, Issue 4 Pages 375-379
Ikuo Satoh

Abstract: Calorimetric microdetermination of zinc(II) ions with use of an apoenzyme thermistor in a flow stream is proposed. Alkaline phosphatase as the selective recognition element was immobilized onto oxirane-acrylic beads (Eupergit-C) and packed into a small polymer column. The flow injection biosensing system was assembled with the immobilized enzyme reactor and a thermistor device for monitoring the enzyme activity. Zinc(II) ions were calorimetrically determined in the range 0.01-1.0 mM for 0.5 mL samples through their activation of the immobilized metal-free alkaline phosphatase (apoenzyme) reactor. The activity of the reactor was assessed by injecting 0.1 mL of 100 mM p-nitrophenyl phosphate solution. Regeneration of the reactor was performed by pumping 20 mM 2.6-pyridine dicarboxylate (pH 6.0) between successive samples. The system could be repeatedly used at least 120 times during 2 months of operation.
Zinc(II) Calorimetry Thermistor

"Determination Of A Small Amount Of A Biological Constituent By The Use Of Chemiluminescence. 16. Highly-sensitive Detection Of Proteins By An Ion-exchange Chromatograph - Chemiluminescence Detector System"
Bull. Chem. Soc. Jpn. 1990 Volume 63, Issue 3 Pages 770-776
Tadashi Hara,Kazuhiko Tsukagoshi and Haruyuki Tsuji

Abstract: The sample was subjected to HPLC on a column (3.5 cm x 4.6 mm) of TSKgel DEAE-NPR with gradient elution (1 mL min-1) with 0 to 0.5 M NaCl in 20 mM Na tetraborate - 0.17 mM HCl (pH 8.04) buffer. Post-column derivatization was achieved by mixing with Cu(II) catalyst solution at 95°C and, after cooling, mixing with 1,10-phenanthroline - H2O2 before chemiluminescence detection.
Protein Chemiluminescence HPLC

"Effect Of Arsenous And Arsenic Acids On The Chemiluminescence Of Luminol In The Absence Of Hydrogen Peroxide And Its Analytical Application"
Bull. Chem. Soc. Jpn. 1994 Volume 67, Issue 8 Pages 2317-2319
Hiroyuki Sakai, Terufumi Fujiwara and Takahiro Kumamaru

Abstract: A FIA system is proposed for the determination of As(III) and As(V) based on a previously described system (Cf. Ibid., 1993, 66, 3401). Sample was injected into a flow stream of 0.75 mM HClO4 of pH 3.2 which passed into a cation-exchange column (20 cm x 4.9 mm i.d.) of SCX-1. The eluate was mixed with a reagent stream of 0.8 mM luminol in 3 mM KOH of pH 11.1 in a coiled flow cell. The chemiluminescence was measured. Calibration graphs were linear for 0.5-15 µg/ml of As(III) and As(V) with detection limits of 100 ng/ml. RSD (n = 5) were 6.1 and 6.9% for 3 µg/ml of As(III) and As(V), respectively. The method was applied to the determination of As in environmental certified reference samples.
Arsenic Environmental Chemiluminescence Ion exchange

"Simultaneous Determination Of Components In Food By FIA Including Parallel Configuration Of Enzyme Columns"
Bunseki 1990 Volume 1990, Issue 5 Pages 379-383
Matsumoto, K.

Abstract: A review is presented, with 8 references, of the use of FIA and immobilized-enzyme columns in the determination of components, e.g., glucose, fructose, sucrose, lactic acid and ethanol in food products. Procedures and instrumentation are discussed.
Glucose Fructose Sucrose Ethanol Lactic acid Food

"Determination Of Trace Amounts Of Nitrite And Nitrate By Flow Injection Spectrophotometry"
Bunseki Kagaku 1982 Volume 31, Issue 12 Pages 732-733
Susumu NAKASHIMA, Masakazu YAGI, Michio ZENKI, Akinori TAKAHASHI, Kyoji TOEI

Abstract: A system has been developed for the determination of nitrite and nitrate ions by flow injection analysis. The flow lines were made from polytetrafluoroethylene (PTFE) tubing. For the nitrite determination a 650 µl of sample is injected into a stream of 0.04 % (w/v) p-aminoacetophenone (p-AAP) solution in 47 mM hydrochloric acid, and flows down a mixing coil (1 mmφ x 1 m) in a thermostated bath at 45°C. The mixture meets a stream of 0.11 % (w/v) m-phenylene-diamine dihydrochloride (m-PD) solution in 1.2 mM hydrochloric acid. After the mixing coil (1 mmφ x 1 m, 45°C), the absorbance at 456 nm is measured by a spectrophotometer with a 10-mm flow-through cell (8 µl) against water as reference. For the nitrate determination a 650 µl of sample is injected into 1.2 mM EDTA carrier solution (pH 9.8) and passed through a copperized cadmium column {3 mmφ x 70 mm, particle size: (0.52) mm} to convert quantitatively nitrate to nitrite. Then, the carrier solution is merged into the stream of a mixed reagent solution of 0.02 % (w/v)p-AAP and 0.055 % (w/v) m-PD in 24 mM hydrochloric acid. After the mixing coil (1 mmφ x 1 m, 45°C), the absorbance is measured at 456 nm. Sampling rate was 30 samples per hour. The relative standard deviations (n= 10) were 0.97 % and 0.89 % for 10 µg/l and 30 µg/l of nitrite-nitrogen, respectively, and 0.95 % and 0.66 % for 0.1 mg/l and 0.3 mg/l of nitrate-nitrogen, respectively. A detection limit was 0.4 µg/l and 2 µg/l for nitrite- and nitrate-nitrogen, respectively.
Nitrite Nitrate Spectrophotometry

"Continuous Spectrophotometric Determination Of Calcium In Silicates By Flow Injection Analysis"
Bunseki Kagaku 1985 Volume 34, Issue 7 Pages T98-T103
Oguma, K.;Kato, Y.;Kuroda, R.

Abstract: The rock sample (100 mg) was fused with Li2CO3 (300 mg) and H3BO3 (300 mg), the melt was dissolved in 1 M HCl (to 100 ml), and a 1 mL aliquot of the solution was applied to a column of cellulose phosphate (to remove Fe(III) and other polyvalent cations). The Ca-containing fraction of the percolate was diluted to 25 mL and made 0.5 M in HCl, and a 311 µL portion of the solution was injected into the flow system. Calcium was determined, as a complex with o-cresolphthalein complexan, by spectrophotometry, with use of quinolin-8-ol as masking agent for Mg. The results obtained for 14 standard rocks were in good agreement with the reported values; for the determination of 1 to 2.5% and >3% of CaO, the coefficient of variation were 1 to 1.6% and 0.2 to 0.8%, respectively. The flow injection sampling rate was 40 h-1
Calcium Geological Silicate Spectrophotometry

"Spectrophotometric Determination Of Nitrate Ion Using Nitrosation/flow Injection Analysis"
Bunseki Kagaku 1987 Volume 36, Issue 3 Pages 207-209
Rui, S.C.;Motomizu, S.;Toei, K.

Abstract: Sample solution was injected into a stream of 1 mM EDTA (pH 8) and passed through a reduction column (30 cm x 2 mm) packed with copperized cadmium. The stream was then mixed with 0.8 mM NN-1,1'-phenyliminodipropan-2-ol - 0.35 M HCl - 0.15 M H3PO4 and passed through a reaction coil (2 m x 0.5 mm) at 80°C. The resulting stream was passed through a cooling coil (50 cm x 0.5 mm) before spectrophotometric detection at 500 nm. The calibration graph was rectilinear up to 0.2 mM NO3-. The limit of detection was 1 µM-NO3- and the coefficient of variation (n = 10) was 0.4%. The sampling rate was 40 h-1. Nitrate was determined by this method in river water at 10 µM level.
Nitrate River Spectrophotometry

"Rapid Determination Of Zinc In Seawater By Column Preconcentration/AAS"
Bunseki Kagaku 1987 Volume 36, Issue 3 Pages 213-216
Hirata, S.;Honda, K.

Abstract: Sea-water (1 L) adjusted to pH 2.2 with 1 mL of concentrated HNO3) was mixed (6.0 mL min-1) with a stream of ammonium acetate buffer (pH 7; 0.5 mL min-1) and passed through a column (16 mm x 3.2 mm) of Chelex-100. The column was washed with water and the chelated Zn was eluted with similar, equals160 l of 2 M HNO3 (3.0 mL min-1) and determined by AAS. The limit of detection was 0.5 ppb of Zn, and the coefficient of variation was 2.7% for 10 ppb of Zn. The sampling rate was ~30 h-1.
Zinc Sea Spectrophotometry

"Determination Of Nitrite, Nitrate And Ammonium Nitrogens In Soil By FIA"
Bunseki Kagaku 1989 Volume 38, Issue 9 Pages 413-418
Shirato, F.;Okajima, Y.;Maekoya, C.;Takata, Y.

Abstract: For determination of NO2-, N-(1-naphthyl)ethylenediamine reagent (40 µL) was injected into water (carrier solution) on either side of the sample solution by using a 16-port injection valve. The stream was passed to a PTFE reaction coil (10 m x 0.5 mm) operated at 90°C, and the absorbance was measured at 520 nm. Nitrate was determined similarly after its reduction to NO2- on a glass column (30 cm x 3 mm) of Cu - Cd (0.5 to 2 mm). For NH4+-N, NH3 was liberated by 1 M NaOH (200 µL) injected on both sides of the sample solution, separated with use of a tubular microporous PTFE membrane and determined by the indophenol method. Absorbance was measured at 630 nm. Beer's law was obeyed for 0.1 to 7, 1 to 20 and 1 to 150 ppm of NO2-, NO3- and NH4+-N, respectively. The coefficient of variation were 0.3 to 0.5%. The analysis time was 10 min per sample.
Ammonium, nitrogen Nitrite Nitrate Environmental Spectrophotometry

"Indirect Spectrophotometric Determination Of Fluoride By FIA Using Arsenazo III - Uranium Complex"
Bunseki Kagaku 1989 Volume 38, Issue 9 Pages 424-428
Zenki, M.;Sai, K.;Ye, Y.;Toei, K.

Abstract: Lanthanum (III), Th(IV) and U(VI) complexes of arsenazo III were evaluated as reagents. Optimum arsenazo III concentration, metal ion concentration, pH, reaction coil length and sample volume were investigated. The U(VI) complex was preferred. A 48 µM-arsenazo III solution (pH 2.8) was used as reagent solution Sample solution (196 µL) was injected into water (carrier solution); PTFE tubing (20 cm x 0.5 mm) was used as the reaction coil. The absorbance was measured at 606 nm. Cation interference was eliminated with use of a cation-exchange column. The calibration graph was rectilinear up to 1.5 ppm of F- and the detection limit was 50 ppb. The coefficient of variation was 0.45% for 0.5 ppm of F- (n = 10). The method was applied in determination of F- in well waters. Lanthanum (III), Th(IV) and U(VI) complexes of arsenazo III were evaluated as reagents. Optimum arsenazo III concentration, metal ion concentration, pH, reaction coil length and sample volume were investigated. The U(VI) complex was preferred. A 48 µM-arsenazo III solution (pH 2.8) was used as reagent solution Sample solution (196 µL) was injected into water (carrier solution); PTFE tubing (20 cm x 0.5 mm) was used as the reaction coil. The absorbance was measured at 606 nm. Cation interference was eliminated with use of a cation-exchange column. The calibration graph was rectilinear up to 1.5 ppm of F- and the detection limit was 50 ppb. The coefficient of variation was 0.45% for 0.5 ppm of F- (n = 10). The method was applied in determination of F- in well waters.
Fluoride Environmental Spectrophotometry

"Simultaneous Determination Of L-malate And Ethanol In Wine By A Sensor Based On Oxygen Consumption Including Parallel Configuration Of Enzyme Columns"
Bunseki Kagaku 1990 Volume 39, Issue 11 Pages 723-727
Ukeda, H.;Nakada, Y.;Matsumoto, K.;Osajima, Y.

Abstract: A flow injection analysis system (illustrated) was developed consisting of two parallel enzyme reactors with a single O electrode. L-Malate (I) was determined by injecting sample solution into a carrier stream of 0.05 M pyrophosphate buffer (pH 9.0) saturated with vitamin K3 (0.5 mL min-1). The stream was mixed with NAD solution and the mixture was passed through a malate dehydrogenase - diaphorase enzyme reactor. Ethanol (II) was determined by injecting sample solution into a stream of 0.05 M phosphate buffer (pH 8.0; 1.0 mL min-1) and the mixture was passed through an alcohol oxidase enzyme reactor. Sample solution was injected simultaneously into both reactors. Calibration graphs were rectilinear from 90 to 900 µM I and from 18 to 50 mM II. The method was applied in the simultaneous determination of I and II in wine. Results were compared with those by HPLC and the F-kit method.
l-Malate Ethanol Wine Electrode HPLC Sensor

"FIA Of Cationic Surfactants Using Plasticized Poly(vinyl Chloride)-membrane Electrode"
Bunseki Kagaku 1991 Volume 40, Issue 1 Pages 1-6
Masadome, T.;Imato, T.;Ishibashi, N.

Abstract: An FIA system was proposed for determining cationic surfactants which incorporates an anion-exchange resin column, aqueous 50% methanol as mobile phase and a plasticized poly(vinyl chloride)-membrane electrode with phthalic acid 2-ethylhexyl ester as detector. The calibration graph was rectilinear from 0.5 to 10 µM-dodecyltrimethylammonium ion and the detection limit was 10 nM. Inorganic electrolytes and anionic and nonionic surfactants did not interfere. The method was applied in the determination of trace cationic surfactants in river water.
Surfactants, cationic River Electrode

"FIA Of Non-ionic Surfactants Using A Plasticized Poly(vinyl Chloride)-membrane Electrode And A Micro-column Packed With An Ion-exchange Resin"
Bunseki Kagaku 1991 Volume 40, Issue 1 Pages 7-11
Masadome, T.;Imato, T.;Ishibashi, N.

Abstract: An FIA system was proposed for determining non-ionic surfactants which incorporates an ion-exchange resin column, aqueous 50% methanol as mobile phase and a plastizized poly(vinyl chloride)-membrane electrode as detector. The calibration graph was rectilinear from 40 to 500 µM-Triton X-100 and the detection limit was 10 µM. Inorganic electrolytes did not interfere. The method was applied in the analysis of detergents.
Surfactants, non ionic Commercial product Electrode Ion exchange

"Spectrophotometric Determination Of Sodium And Potassium By FIA After Separation On A Cation-exchanger Column And Solvent Extraction"
Bunseki Kagaku 1991 Volume 40, Issue 5 Pages T107-T112
Yoshida, K.;Motomizu, S.

Abstract: Sodium and K ions were separated by passing aqueous sample solution through a cation-exchanger column (1.2 cm x 2.5 mm) with 0.4 mM EDTA.3Li as the eluent stream. The eluate was made alkaline (pH 10) by passing through the anion-exchanger membrane tubing (1 m) kept in 0.1 M LiOH, then mixed with benzene - chlorobenzene (1:1) containing 3 mM tetrabromophenolphthalein ethyl ester and 2 mM dicyclohexano-18-crown-6 and passed through an extraction coil (2 m x 0.5 mm). The absorbance of the organic phase was measured at 615 nm after phase separation with use of a PTFE porous membrane. Calibration graphs were rectilinear up to 0.5 mM Na+ and 80 µM-K+. Sample throughput was 12 h-1. The method was used in the analysis of river and tap water.
Potassium Sodium River Water Spectrophotometry Sample preparation

"FIA Of Urine Oxalate By The Titanium(IV) - 4-(2'-pyridylazo)resorcinol Reagent"
Bunseki Kagaku 1991 Volume 40, Issue 7 Pages 343-347
Matsubara, C.;Sakai, K.;Takamura, K.

Abstract: Urine (5 µL) was injected into a carrier (0.3 mL min-1) and passed through a column of immobilized oxalate oxidase. The produced H2O2 was determined by measuring the absorbance of the complex formed with the cited reagent at 508 nm. The calibration graph was rectilinear from 2 µM to 1 mM oxalate; coefficient of variation (n = 10) at 40 µM was 1.0%. The throughput rate was 40 samples h-1. Metallic ions did not interfere.
Oxalate Urine

"Determination Of Creatinine By Flow Analysis Using A Reactor Type Immobilized Enzyme Column And A Lead Phosphate Glass Electrode"
Bunseki Kagaku 1991 Volume 40, Issue 10 Pages 531-535
NOMURA Tsuyoshi MORI Hiroyuki

Abstract: Creatinine (I) was determined with use of a flow injection system (illustrated) comprising a column of CPG-10 glass beads immobilized with I - deiminase and a membrane electrode of lead phosphate glass containing silver oxide; which was used as a sensitive sensor for NH3, produced from the enzymatic reaction of I. Under optimum conditions viz, 1 mM NaOH - 1 mM Na2SO4 (pH 10) as carrier solution at 30°C, the calibration graph was rectilinear for 0.14 to 5.66 mg for 25 mL-1 of I.
Creatine Electrode Electrode

"Determination Of Seven Trace Elements In Environmental Water Samples By Inductively Coupled Plasma Mass Spectrometry With Online Preconcentration"
Bunseki Kagaku 1993 Volume 42, Issue 7 Pages 423-428
Akatsuka, K.;McLaren, J.W.;Berman, S.S.

Abstract: An online pre-concentration method was studied to allow the simultaneous determination of Mn, Co, Ni, Cu, Zn, Cd and Pb in 5 mL environmental water samples by inductively coupled plasma mass spectrometry. A semiautomated system with a microprocessor-controlled high performance quaternary gradient pump and valves was used to lead and transport the mobile phase. The system includes a column containing silica-immobilized 8-hydroxyquinoline. The pH of the samples was adjusted to 8 to improve the retention of several elements, in particular manganese. Quantitative elution from the column took 3.5 min with a 1.5 M HCl/0.6 M HNO3 mixture at a flow rate of 2.0 mL min-1. Mn and Co were determined by a standard additions technique, and stable isotope dilution was applied for Ni, Cu, Zn, Cd and Pb. The good precision and accuracy of this method are demonstrated by analyzing standard samples of riverine water (SLRS-2), estuarine water (SLEW-1) and coastal seawater (CASS-2). The detection limits of the method range from 7 ng L-1 for Cd to 130 ng L-1 for Zn. [References: 18]
Manganese Cobalt Nickel Copper Zinc Cadmium Lead NRCC SLRS-2 NRCC SLEW-1 NRCC CASS-2 Sea River Mass spectrometry

"Flow Injection Sample Processing In Atomic Absorption Spectrometry"
Chem. Anal. 1992 Volume 37, Issue 2 Pages 111-138
Trojanowicz, M.A.;Olbrych Sleszynska, E.

Abstract: A review is presented, with 100 references, of the coupling of flow injection sample processing with flame AAS detection. The nebulization process in AAS measurements, sensitivity, detectability and precision are discussed. Various aspects of coupling flow injection sample processing with flame atomic absorption spectroscopy detection are discussed with special consideration to nebulization processes and sensitivity, detectability, and precision of determination are discussed. Several anal. procedures involving different calibration techniques, using organic solvents, solvent extraction, microcolumns with solid sorbents, Donnan dialysis or precipitation for analyte pre-concentration or separation are reviewed. 100 Refs.
Spectrophotometry Sample preparation

"Preconcentration On Chelating Sorbents In Flow Injection Analysis Using Flame Atomic Absorption Detection"
Chem. Listy 1990 Volume 84, Issue 9 Pages 934-941
Komarek, J.;Kuban, V.;Zdrahal, Z.

Abstract: In this review, flow injection systems incorporating one, two or more columns are described and illustrated in schematic diagrams. The effects of column or sorbent type and of operating conditions on the efficiency of pre-concentration. and elution of analytes are discussed. (15 references).
Spectrophotometry

"Simultaneous Determination Of 2-deoxyglucoseSimultaneous Determination Of 2-deoxyglucose"
Chem. Pharm. Bull. 1990 Volume 38, Issue 4 Pages 963-965
Umegae, Y.;Nohta, H.;Ohkura, Y.

Abstract: Sample solution (0.1 ml) was injected on to a TSK gel Sugar AXG column (15 cm x 4.6 mm) operated at 60°C with 1 M borate buffer (pH 9.0) as mobile phase (0.4 mL min-1). The effluent was mixed with 15 mM meso-1,2-bis-(4-methoxyphenyl)ethylenediamine in aqueous 30% ethanol - 0.6 M NaOH (0.3 mL min-1) and passed through a reaction coil (20 m x 0.5 mm) at 140°C and a cooling coil (1 m x 0.5 mm), and the fluorescence was measured at 460 nm (excitation at 330 nm). Calibration graphs were rectilinear for up to 100 nmol injected, the detection limits for 2-deoxy-D-ribose, 2-deoxyglucose (I), rhamnose, L-fucose and glucose (II) were 21, 26, 27, 18 and 28 pmol, respectively, and the respective coefficient of variation (n = 10) at 1 nmol were 1.7, 1.5, 2.1, 1.5 and 1.9%. The method was applied to determine I and II in deproteinized serum, with L-fucose as internal standard.
Glucose 2-Deoxyglucose Serum Rat HPLC Fluorescence

"Flow Injection Calorimetric Biosensing Of Cobalt(II) Ions"
Chem. Sens. 1991 Volume 7, Issue Suppl. A Pages 61-64
Ikuo SATOH and Keiji WATANABE

Abstract: Alkaline phosphatase (I) apoenzyme was immobilized on oxiran - acrylic beads and packed into a column, which was then mounted in a thermistor probe. Tris - HCl buffer (0.1M, pH 8.0, containing 1 M NaCl) was pumped through the system at 1 mL min-1 and the sample solution was introduced by a rotary injection valve. The Co was determined in the range 0.04 to 1 mM by its partial re-activation of the I as assessed by injecting 0.1 mL of 0.1 M 4-nitrophenyl phosphate and measuring the temperature change, which was related to the concentration. of Co2+ applied to the column. The column was regenerated by using 40 mM pyridine-2,6-dicarboxylate (pH 6.0) as cofactor complexing agent.
Cobalt(II) Calorimetry Sensor Thermistor

"The Multiple System CHROMES/CHROMAS For Detection In HPLC And Flow Injection Analysis"
Chem. Tech. 1990 Volume 42, Issue 11 Pages 484-486
Mennig, F.;Haessner, R.;Moros, R.;Mattusch, J.;Werner, G.

Abstract: The cited system (Ingenieurbetrieb fuer die Anwendung der Mikroelektronik, Erfurt) is intended for the collection and evaluation of the output from several recording instruments, for which it has eight analogue input and output channels linked to a microprocessor. For application to HPLC, the analogue signals from several selective detectors operating in series are digitized and delivered to a computer. The acquisition and storage of the data up to this point are controlled by the program CHROMES, written in Turbo-Pascal. For the subsequent calculation of the area of each Gaussian peak, readings at 40 data points are required. The stored data are evaluated off-line by the program CHROMAS; this can reproduce the output graphically on a screen and smooth the output by the running-mean or least-squares method. First and second derivatives of the recorded curves are used for peak recognition.
HPLC

"Biosensor Based On Chemiluminescence For Serum Uric Acid Determination"
Shengwu Gongcheng Xuebao 1995 Volume 11, Issue 3 Pages 233-238
Liu Jianguo Guo Jian Li Gaoxiang

Abstract: A biosensor based on luminol chemiluminescent reaction and immobilized uricase column for serum uric acid determination has been developed. The response time by the sensor for various concentrations of serum uric acid was 47 sec with a 17 µL sample volume at 40 samples per hr. The linear range of standard curve was from 1 mg/dL up to 20 mg/dL of serum uric acid. The imprecision within a day was 3.22% to 4.36%. The day-to-day imprecision was 6.18% to 7.80%. The recovery rate by the method was 93% to 109%. Compared with the standard colorimetric method employed, the enzymatic kit revealed that the linear regression and correlation coefficient were Y = 0.4 + 0.938x and r = 0.9909, respectively. The immobilized uricase column retained 94% of its original activity even after over 2000 runs for five and half months of continual usage.
Uric acid Blood Serum Chemiluminescence Sensor

"Glass Insert In Stop-flow Split Injection"
Chromatographia 1990 Volume 29, Issue 7-8 Pages 385-388
Guanghui Liu and Zhenxue Xin

Abstract: The influence was studied of the insert design and of the sample size on the accuracy and precision of analytical results obtained for a sample of wide boiling-range alkanes by using stop-flow injection. The size of the gaseous sample plug and its position with respect to the column inlet and to the top of the insert during evaporation were critical to prohibit sample vapor overflow and aerosol splitting. The proper insert design was established and a sample volume of 0.5 µL was recommended.

"Urea And Lactate Determined In 1-mu-L Whole-blood Samples With A Miniaturized Thermal Biosensor"
Clin. Chem. 1994 Volume 40, Issue 12 Pages 2282-2287
Bin Xie,' Ulrika Harborn, Michael Mecklenburg, and Bengt Danielsson

Abstract: A miniaturized flow injection thermal biosensor was developed for the determination of urea and L-lactate in undiluted blood in 1 µL samples. The sensor employed a small enzyme column constructed of stainless steel tubing and microbead thermistors. Urease and lactate oxidase/catalase were separately immobilized onto controlled-pore glass beads, which, in turn, were charged into the enzyme column. With a flow rate of 70 µL/min, linear analytical ranges from 0.2 to at least 50 mmol/L and 0.2 to 14 mmol/L were obtained for urea and lactate, respectively. The relative standard deviations (CVs) for measurements of analyte in buffer were 0.91% for urea and 1.84% for lactate. For urea in whole blood, the CV for 50 determinations was 4.1%. Contrived samples containing various concentrations of urea and L-lactate in whole blood were determined with this sensor and with a spectrophotometric method. Comparisons of the results gave correlation coefficients of 0.989 and 0.984 for 30 blood urea and 30 blood lactate assays in concentrations ranging from 4 to 20.9 mmol/L and from 1.7 to 12.7 mmol/L, respectively.
Urea Lactate Whole Sensor Thermistor Clinical analysis

"Bioluminescent Assay For Serum Adenosine Deaminase With Immobilized Bacterial L