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
Website: @unf

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Classification: Water

Citations 308

"Incidence Of Transitional Cell Carcinoma And Arsenic In Drinking Water: A Follow-up Study Of 8,102 Residents In An Arseniasis-endemic Area In Northeastern Taiwan"
Am. J. Epidemiol. 2001 Volume 153, Issue 5 Pages 411-418
Hung-Yi Chiou, Shu-Ti Chiou, Yi-Hsiang Hsu, Yi-Li Chou, Chin-Hsiao Tseng, Min-Li Wei, and Chien-Jen Chen

Abstract: A significant association between ingested arsenic and bladder cancer has been reported in an arseniasis-endemic area in southwestern Taiwan, where many households share only a few wells in their villages. In another arseniasis-endemic area in northeastern Taiwan, each household has its own well for obtaining drinking water. In 1991-1994, the authors examined risk of transitional cell carcinoma (TCC) in relation to ingested arsenic in a cohort of 8,102 residents in northeastern Taiwan. Estimation of each study subjects individual exposure to inorganic arsenic was based on the arsenic concentration in his or her own well water, which was determined by hydride generation combined with atomic absorption spectrometry. Information on duration of consumption of the well water was obtained through standardized questionnaire interviews. The occurrence of urinary tract cancers was ascertained by follow-up interview and by data linkage with community hospital records, the national death certification profile, and the cancer registry profile. Cox proportional hazards regression analysis was used to estimate multivariate-adjusted relative risks and 95% confidence intervals. There was a significantly increased incidence of urinary cancers for the study cohort compared with the general population in Taiwan (standardized incidence ratio = 2.05; 95% confidence interval (CI): 1.22, 3.24). A significant dose-response relation between risk of cancers of the urinary organs. especially TCC, and indices of arsenic exposure was observed after adjustment for age, sex, and cigarette smoking. The multivariate-adjusted relative risks of developing TCC were 1.9, 8.2, and 15.3 for arsenic concentrations of 10.1-50.0, 50.1-100, and >100 µg/liter, respectively, compared with the referent level of less than or equal to 10.0 µg/liter.
Arsenic Spectrophotometry

"A Bead Injection System For Copper Determination"
Anal. Lett. 2000 Volume 33, Issue 5 Pages 929-940
Claudio C. Oliveira; Elias A. G. Zagatto; Jaromir Ruzicka; Gary D. Christian

Abstract: A bead injection system for copper determination is proposed. Chelex-100 resin beads are introduced in the system as a suspension that is trapped in the Jet Ring Cell. The passage of the sample zone by the beads promotes the sorption of Cu(II). When the colorimetric reagent (APDC) perfuses the beads it reacts with copper ions, forming a colored complex that is monitored at 436 nn. After the measurement, the spent beads are sent to waste and a new portion of fresh beads is trapped in the system. The bead injection system is versatile and can be used to concentrate analyte in different sample volumes, permitting determinations of a wide range of copper concentrations. The detection limit is 0.5 µg L-1 with a 500 µL sample, and 1.2 µg L-1 a 100 µl sample.
Copper(II) Spectrophotometry Chelex Preconcentration Bead suspension Jet ring cell APDC

"Experimental Aspects Of Mechanistic Studies On Aqueous Ozone Decomposition In Alkaline Solution"
Ozone Sci. Eng. 2000 Volume 22, Issue 3 Pages 287-304
Attila Nemes; Istvan Fabian; Gilbert Gordon

Abstract: Ozone decomposition in aqueous solution was studied by the stopped flow method over the pH 10.4 - 13.2 range at 25±0.1°C and I = 0.5 M NaClO4. At 260 nm the molar absorptivity of aqueous ozone was determined to be 3135±22 M-1 cm-1. It was shown that various experimental factors may significantly alter the course of the reaction. Even small amounts of H2O2 absorbed by the plastic parts of the stopped-flow instrument can affect the kinetic features of the reaction for an extended period of time. Under strictly controlled experimental conditions sufficiently reproducible data could be obtained for the decomposition. The data were evaluated by comparing experimental and simulated kinetic traces. A detailed kinetic model was developed which is able to predict the decay and life-time of ozone as well as the formation and decomposition of the ozonide ion radical (O3-) over the pH 10.4 - 13.2 range.
Ozone Spectrophotometry Stopped-flow Kinetic

"Determination Of Octanol-water Partition Coefficients Using A Micro-volume Liquid-liquid Flow Extraction System"
Anal. Chim. Acta 2000 Volume 423, Issue 1 Pages 137-144
Karin Carlsson and Bo Karlberg

Abstract: An extraction system consuming less than 1 µl of sample and organic solvent (combined volume) has been developed for the determination of 1-octanol-water partition coefficients (log K-ow). The system comprises a capillary, a micro-volume stepper piston pump, a peristaltic pump and a detector. The stepper piston pump is programmable, enabling full control and selection of each step in the pumping sequence. Coupled to the pump is a 250 µm i.d. silica capillary, extending 240 mm from its aperture to the detector cell which houses an on-capillary spectrophotometric detector allowing direct monitoring of both the aqueous sample and the organic solvent plugs. Programmed portions of air, aqueous sample, organic solvent and a second portion of air are sequentially introduced into the capillary from respective vials. Typically, 250 nl of both the aqueous sample and organic solvent were introduced in the trials reported here. Since all liquids are aspirated directly into the capillary there is no need to pre-flush the system (as is required in most other continuous flow systems). Thus, the entire portions of the sample and the organic solvent are used in the analysis. The analytical procedure used for determining octanol-water partition coefficients is essentially an automated and miniaturised version of the batch method recommended in the OECD manual. The log K-ow values obtained agreed well with literature data and/or manual batch determinations. Typical analysis time was 4 min when applying a mean flow rate of about 4 µl min-1, including a wash cycle between the samples. The system is suitable for screening purposes and could readily be automated using a robot.
1-Octanol Spectrophotometry Solvent extraction Partition coefficients Automation Small sample

"Spectrophotometric Determination Of Ozone In Ozonized Air Currents With Chemical Gas-liquid Transfer Using A Microreactor"
Anal. Chim. Acta 1999 Volume 380, Issue 1 Pages 93-99
Ênio L. Machado, Marcelo B. da Rosa, Érico M. M. Flores, José N. G. Paniz and Ayrton F. Martins

Abstract: The spectrophotometric determination of ozone by measurement of its corresponding iodine-starch complex at 580 nm was realized using a flow injection system with chemical gas-liquid transfer microreactor. The flow injection system with a gas-liquid transfer microreactor (Vigreux type microcolumn, 500 µl) was designed to use a reagent solution (1% (m/v) potassium iodide, 0.1 mol L-1 boric acid, and 1% (m/v) starch) for ozonization at low residence time. Ozonizated air currents were constantly passed through a sampling loop at various flow rates, and then injected by countercurrent in the microreactor to ozonizate the reagent solution. The volume of the ozonizated air sampling loop was 32 mi, and 500 µl for the reagent solution. The best results were: ozone chemical/physical transference of 95%, an output rate of 120 samples per hour, a detection limit of (3 s)=0.4 mg O-3 L-1, a work range from 0.4 to 10.6 mg O(3)l-1, and a relative standard deviation of 1.7 (n=5, 1.2 mg O-3 l-1). Ozone production rate (mg O-3 h-1) was determined from a homemade ozonizator (3 kV, air as feed gas), and ozone off-gas from ozonization of agrochemical factory wastewater. Using this procedure, several problems of gas phase ozone determination were surpassed: low output rate, excessive handling, and high consumption of the reagent solution. Additionally, direct ozone sampling by flow injection system was made possible.
Ozone Spectrophotometry Reactor Optimization Extraction

"Molecularly Imprinted Ion Exchange Resin For Purification, Preconcentration And Determination Of UO22+ By Spectrophotometry And Plasma Spectrometry"
Anal. Chim. Acta 1999 Volume 397, Issue 1-3 Pages 173-181
Sue Y. Bae, Glen L. Southard and George M. Murray

Abstract: A new ion exchange resin based on a UO22+ imprinted polymer was used for the removal and concentration of UO22+ from aqueous solution prior to spectroscopic determination. The imprinted resin performance is compared with results obtained using Chelex-100 ion exchange resin. The UO22+ ion imprinted resin, being more selective towards UO22+ ion, provides a fast and virtually interference-free pre-concentration procedure. The separation provides for the elimination of interferences in photometry and plasma spectroscopy, improves accuracy and lowers limits of detection. The performance of the imprinted resin allows for the development of a field test kit for the determination of UO22+ in environmental samples based on colorimetric analysis. A mini-column permitted large enrichment factors to be attained, provided rapid processing of large volumes and quantitative recovery of UO22+ With an eluent suitable for photometric analysis.
Uranyl ion Spectrophotometry Spectrophotometry Ion exchange Resin Chelex Preconcentration Method comparison

"Method Of Analysis In Continuous Flow For The Determination Of V(V) In Water"
Afinidad 2000 Volume 57, Issue 486 Pages 131-134
Miriam E. Palomeque

Abstract: A spectrophotometric method for the determination of vanadium(V) by flow injection analysis (FIA), based on the complex formation between the analyte and alizarin red in CTAB at pH 4.0, is proposed. The concentration linear range is 0 to 6.9 µg mL-1, with a reproducibility of 1.9%, a detection limit of 0.2 µg mL-1 and a sampling frequency of 300 h-1. This is a rapid and suitable method to carry out the V(V) control and quantization in water samples.
Vanadium(V) Spectrophotometry

"Simultaneous Quantitative Analysis Of Overlapping Spectrophotometric Signals Using Wavelet Multiresolution Analysis And Partial Least Squares"
Talanta 2000 Volume 50, Issue 6 Pages 1163-1173
Shouxin Ren and Ling Gao

Abstract: The mathematical bases and program algorithms of discrete wavelet transform (DWT), multiresolution and Mallats pyramid algorithm were described. The multiresolution analysis (MRA) based on Daubechies orthogonal wavelet basis was studied as a tool for removing noise and irrelevant information from spectrophotometric spectra. After wavelet MRA pre-treatment, eight error functions were calculated for deducing the number of factors. A partial least squares based on wavelet MRA (WPLS) method was developed to perform simultaneous spectrophotometric determination of Fe(II) and Fe(III) with overlapping peaks. Data reduction was performed using wavelet MRA and principal component analysis (PCA) algorithm. Two programs, SPWMRA and SPWPLS, were designed to perform wavelet MRA and simultaneous multicomponent determination. Experimental results showed the WPLS method to be successful even where there was severe overlap of spectra.
Iron(2+) Iron(III) Spectrophotometry Partial least squares Wavelet transform Speciation

"Spectrophotometric Determination Of PK(a) Values Based On A PH Gradient Flow Injection System"
Anal. Chim. Acta 2000 Volume 408, Issue 1-2 Pages 135-143
Javier Saurina, Santiago Hernández-Cassou, Romà Tauler and Anna Izquierdo-Ridorsa

Abstract: This paper describes a pH gradient flow injection method for fast spectrophotometric determination of acidity constants. The flow injection system consists of a three-channel manifold in which the sample bolus is injected between acidic and basic zones. Therefore, the front of the flow injection peak is made acidic while the tail of the peak is alkalinized, and consequently, a pH gradient from acidic to basic medium is generated along the flow injection peak in an easy and reproducible way. The whole procedure is composed of two steps; first, the in situ determination of the pH gradient profile by using a standard compound with a known pK(a) value, and second, this pH gradient profile is used to calculate the pK(a) of an unknown compound. An alternating least squares multivariate curve resolution method is used in both steps to resolve the concentration profiles of the acidic and basic species in the standard and in the unknown samples which are the basis of the calculations. The method is tested using several nucleic acid components. An additional advantage of the proposed method is that no pH experimental measurement is needed for the fast determination of pK(a) values. Results obtained using the proposed procedure are consistent with those listed in the literature.
Acidity, constants Nucleic acids Spectrophotometry pH gradient Titrations Multivariate calibration

"A Detailed Study Of Sample Injection Into Flowing Streams With Potentiometric Detection"
Anal. Chim. Acta 1978 Volume 98, Issue 2 Pages 193-203
Zs. Fehér and G. NagyK. Tóth and E. Pungor

Abstract: A new method developed by combining manual or coulometric injection into flowing streams and potentiometric detection is described. The potential-time curves obtained in a flow-through detector as a result of single injections are handled theoretically and examined practically. The effects of experimental parameters, concentrations and flow rates on the signal are discussed. A systematic survey of the potential use of the technique in analysis is given. Species can be determined easily either in the flowing stream or in the injected sample. Some applications in pharmaceutical and other types of analysis are listed, and the main advantages of the technique are summarized.
Bromine Chlorine Cyanide Thiocyanide Indium Enzyme, cholinesterase Uric acid Enzyme, urease Glucose Enzyme, glucose oxidase Urea Nitrogen, urea Potentiometry Coulometric injection

"Flow Injection Analysis Of Calcium In Serum, Water And Waste Water By Spectrophotometry And By Ion-selective Electrode"
Anal. Chim. Acta 1978 Volume 100, Issue 1 Pages 151-165
E. H. Hansen, J. Rika and Animesh K. Ghose

Abstract: The flow injection technique is a fast, reliable, and sensitive method for the determination of Ca in various aqueous as well as serum samples; spectrophotometric or potentiometric detection can be used. At sampling rates of 100-10 samples/h, with 30 µL sample injections, high reproducibility of measurement and low reagent consumption are achieved in both methods. In the spectrophotometric method (with o-cresolphthalein complexon), the anal. readout is available within 12 s after sample injection at a total reagent consumption of 0.75 mL/anal. The potentiometric measurement of the Ca activity in serum is placed on a reliable basis by alternating measurements of serum samples and aqueous standards without incurring any nonreproducible changes in potential between aqueous and serum solutions This permits the simultaneous determination of pH and pCa, the anal. readout being available within 3 s of sample injection. The good agreement between the results obtained with the flow injection method and those attained by atomic absorption and EDTA titrns. as well as pCa stat-measurements show that the new methods are potentially suitable for routine anal.
Calcium pH Spectrophotometry Electrode Potentiometry Method comparison

"Simultaneous Determination Of Nitrate And Nitrite By Flow Injection Analysis"
Anal. Chim. Acta 1980 Volume 114, Issue 1 Pages 191-197
M. F. Giné, H. Bergamin F, E. A. G. Zagatto and B. F. Reis

Abstract: An automatic method for the simultaneous determination of NO3- and NO2- by flow injection analysis is described. NO3- is reduced to NO2- with a copperized Cd column. NO2- is diazotized and coupled with N-(1-naphthyl)ethylenediammonium dichloride. A spectrophotometric detector is used. The merging zones approach is used to minimize reagent consumption. The injector system is arranged so that 2 peaks are obtained, 1 corresponding to NO2- and the other to NO2-+NO3-. A sampling rate of ~90 samples/h is possible; the precision is better than 0.5% for NO2- in the range 0.1-0.5 mg L-1 and 1.5% for NO3- in the range 1.0-5.0 mg L-1. The method was used to analyze soil and water samples.
Nitrate Nitrite Spectrophotometry Reduction column Merging zones Multielement Proportional injector

"A Modeling Approach To Establish Experimental Parameters Of A Flow-through Titration"
Anal. Chim. Acta 1980 Volume 114, Issue 1 Pages 235-246
H. F. R. Reijnders and J. F. Van Staden, G. H. B. Eelderink, B. Griepink

Abstract: A flow-through titrimeter with optical detection and the flow-through titration of sulphate have been studied by using control engineering methods. Qualitative chemical descriptions and systems analysis yield a model covering different precipitation rates of barium sulphate. The validity of the model is proved by comparing simulated and real experiments. Possible uses of the model are indicated. The signal of the titrimeter is shown to be independent of dilution and turbidity, because of the special detection arrangement.
Sulfate Spectrophotometry Turbidimetry Theory Titrations Modeling

"Flow Injection Analysis Of Inorganic Polyphosphates"
Anal. Chim. Acta 1980 Volume 115, Issue 1 Pages 269-277
Yukio Hirai, Norimasa Yoza and Shigeru Ohashi

Abstract: Flow injection analysis is applied to the determination of orthophosphate and polyphosphates, such as diphosphate and triphosphate. A strongly acidic solution containing molybdenum(V) and molybdenum(VI) is used as the carrier so that hydrolysis of polyphosphates and color development of the resultant orthophosphate can be achieved simultaneously. For complete chemical reaction, the temperature of the reaction coil is maintained at 140°C. Application of a back-pressure coil is then necessary to eliminate the noise caused by gas bubbles. Total amounts of inorganic polyphosphates can be determined at a sampling rate of 45 samples per hour with a relative standard deviation of less than 1%. In addition, the flow injection system is shown to be useful as a post-column detector for high-performance liquid chromatography of inorganic polyphosphates. The efficiency of this system is compared with that of an air-segmented flow system.
Polyphosphates Phosphate Diphosphate Triphosphate Phosgene Phospholipids Phosphonate HPLC Spectrophotometry

"The Use Of Ion-selective Electrodes In Manual And Computer Controlled Flow Injection Systems"
Anal. Chim. Acta 1980 Volume 117, Issue 1 Pages 91-98
J. Slanina, W. A. Lingerak and F. Bakker

Abstract: The performance of ion-selective electrodes in a flow injection system under manual or active computer control is discussed. The response of the fluoride-selective membrane electrode was not Nemstian, and depended on several parameters. With appropriate standardization, the results were quite satisfactory. Precision was typically 3%; 60 determinations per hour are possible in the concentration range 20-200 ppb. The detection limits of the electrodes are below the values found m other measurement modes.
Fluoride Electrode Electrode Computer

"Determination And On-site Sampling Of Inorganic And Organic Mercury In Aqueous Samples With Enzyme Reactors"
Anal. Chim. Acta 1981 Volume 125, Issue 1 Pages 45-53
Lars Ögren

Abstract: Micro reactors containing immobilized urease are used for the sampling and determination of mercury ions. When an aqueous sample is passed through the reactor, the mercury ions are collected and bound to the enzyme. The enzyme is partially inhibited and the amount of mercury ions is determined as a decrease in the enzyme activity. The enzyme activity is determined with an ammonia electrode when a urea solution is pumped through the reactor. The selectivity is very high and the operating range is 0-15 nM Hg2+ for 5 mL samples. The mercury can be stored for several days in the reactor before the measurements are made. Organomercury compounds give essentially the same response as inorganic mercury.
Ethylmercury Methylmercury ion Phenylmercury Mercury(II) Electrode Ion exchange Enzyme Reactor

"A Sensitive And Accurate Automatic Coulometric Detector System For Enzymatically Produced Carbon Dioxide"
Anal. Chim. Acta 1981 Volume 131, Issue 1 Pages 133-139
Anders O. Lindberg

Abstract: A system for the determination of carbon dioxide liberated in an enzyme reactor is described. The properties of the system are illustrated by the determination of urea. Enzymatically generated carbon dioxide is expelled by boiling, dried and determined coulometrically. The lowest concentration of urea which can be determined with a relative standard deviation of 5% is 1 M. Compared with other methods based on immobilized enzymes for the determination of compounds as carbon dioxide, this sensitivity constitutes an improvement of about two orders of magnitude. Possible application to sea water is discussed.
Carbon dioxide Urea Coulometry Titrations

"Comparison Of Atomic Absorption Spectrometric, Spectrophotometric And Fluorimetric Methods For Determination Of Aluminum In Water"
Anal. Chim. Acta 1982 Volume 134, Issue 1 Pages 369-373
R. Playle, J. Gleed, R. Jonasson and J. R. Kramer

Abstract: A standard method involving chelation of lead with ammonium pyrrolidinedithiocarbamate and extraction into methyl isobutyl ketone was investigated as to the effect of the pH of chelation on the absorbance and stability of the extracted lead. The maximum sensitivity to lead occurs at low pH values, but rapid degradation of the absorption also occurs at low pH values. Higher pH values give lower sensitivity, but provide better stability with time.
Aluminum Fluorescence Spectrophotometry Spectrophotometry Method comparison

"Determination Of Lead By Continuous-flow Hydride Generation And Atomic Absorption Spectrometry. Comparison Of Malic Acid - Dichromate, Nitric Acid - Hydrogen Peroxide And Nitric Acid - Peroxodisulfate Reaction Matrices In Combination With Sodium Tetrahydr"
Anal. Chim. Acta 1982 Volume 143, Issue 1 Pages 229-236
Kazuo Jin, Mitsuhiko Taga

Abstract: A continuous-flow hydride generator is combined with a heated quartz tube atomizer atomic absorption spectrometer system for the trace determination of lead. Malic acid K2Cr2O7, HNO3-H2O2 and HNO3-(NH4)2S2O3 are all effective for plumbane generation by means of sodium tetrahydroborate. The relative merits of these systems are investigated in terms of sensitivity, efficiency of plumbane generation and interferences. The sensitivities (0.0044 absorbance) obtained under the recommended conditions for the three systems are 3.2, 1.7 and 1.1 ng Pb mL-1, respectively, whereas plumbane generation efficiencies are 33%, 47% and>80%, respectively, for 1 µg Pb mL-1. Silver, Au, Cu and Cd interfere seriously in all reaction systems. A dithizone extraction and back-extraction method is utilized to eliminate interfering ions, followed by reduction of the resulting solution in the peroxodisulphate system. The proposed method is applied to water samples and NBS 1566 oyster tissue.
Lead Spectrophotometry

"Kinetic Determination Of Magnesium And Calcium By Stopped-flow Injection Analysis"
Anal. Chim. Acta 1983 Volume 145, Issue 1 Pages 125-133
Henrik Kagenow and Arne Jensen

Abstract: A kinetic method for the simultaneous determination of magnesium and calcium ions in solution is described. The method is based on the dissociation reactions of cryptand (2.2.2) complexes; a stopped-flow injection technique is used with spectrophotometric monitoring of the phthalein complexone complexes of the released metal ions. Analyses were done at a rate of 80 h-1, with injected sample volumes of 80 µL. A microcomputer system for data acquisition and control of the system is described.
Calcium Magnesium Spectrophotometry Kinetic Stopped-flow

"Membrane Separation In Flow Injection Analysis. Gas Diffusion"
Anal. Chim. Acta 1983 Volume 151, Issue 1 Pages 359-369
W. E. Van Der Linden

Abstract: A general expression is derived for the membrane transport process in a flow-through unit as commonly used in flow injection systems. The validity of the formulae was tested for gas-diffusion membranes by using compounds with different volatilities such as ammonia, carbon dioxide and acetic acid. Several microporous hydrophobic membranes were tested. A new module design is proposed.
Acetic acid Ammonia Carbon dioxide Spectrophotometry Gas diffusion Membrane Review Theory

"The Spectrophotometric Determination Of Hydroxylamine Alone And In The Presence Of Hydrazine By Flow Injection Analysis"
Anal. Chim. Acta 1983 Volume 153, Issue 1 Pages 277-280
G. C. M. Bourke, G. Stedman and A. P. Wade

Abstract: The method is based on the manual procedure of Dias et al. (Anal. Abstr., 1979, 37, 2B143). The sample solution was mixed with a three fold volume of 10 mM ferrozine [3-(2-pyridyl)-5,6-bis-(4-sulfophenyl)-1,2,4-triazine (monosodium salt)], a 0.41 mL portion was injected into a carrier stream (1.19 mL min-1) of 0.3 M chloroacetic acid - 0.273 M NaOH - 3.1 mM Fe(III), and the absorbance was measured with use of the flow-through photo-transducer of Sly et al. (J. Autom. Chem., 1982, 4, 186), which incorporated a light-emitting diode (giving max. emission at 565 nm) and a phototransistor. Calibration graphs were rectilinear for 10 µM to 0.1 mM hydroxylamine in the sample solution, the limit of detection was 1 µM, and the repeatability of peak heights was 0.7%. A 20-fold excess of hydrazine can be tolerated; when larger amounts are known to be present, hydrazine can be determined separately and a correction applied.
Hydroxylamine Spectrophotometry Computer Optimization Light emitting diode Photodiode

"Atomic Absorption Spectrometric Method For Individual Determination Of Chromium(III) And Chromium(VI) By Atomization Of Chromium From A Chelating Resin In A Graphite Tube"
Anal. Chim. Acta 1983 Volume 153, Issue 1 Pages 15-22
Akinori Isozaki, Kazuhiro Kumagai and Satori Utsumi

Abstract: To determine Cr(III), the test solution (250 ml) is buffered at pH 4.0 with acetate and stirred for 20 min with 0.1 g of Chelex-100 (-400 mesh; NH4+ form); the resin is then collected on a membrane filter (2 µm pores) and suspended in 5 mL of H2O.A 10 µL portion of the suspension is injected into a graphite-tube atomizer and dried at 300°C for 15 s, the residue is charred at 1200°C for 75 s and step-atomized at 2500°C for 10 s with a continuous-flow of Ar (3 l min-1), and the absorption-peak area is measured at 357.9 nm (hollow-cathode lamp); no background correction is necessary. To determine Cr(VI), the filtrate remaining after removal of Cr(III) is treated with 5 mL of 3 M HCl and 5 mL of aqueous 3% H2O2, and the resulting Cr(III) is determined as described above. Interference from Fe(III) and Al is prevented by masking with 1,2-diaminocyclohexanetetra-acetic acid.Up to 1 g L-1 of Cl-, NO3- or SO42- has no effect. Results on five synthetic solution containing 1 to 2 µg L-1 of total Cr agreed well with known values. For 1 µg L-1 of Cr(III) and of Cr(VI), the coefficient of variation (n = 7) were 2.3 and 3.7%, respectively.
Chromium(III) Chromium(VI) Spectrophotometry Chelex Interferences Chelation Reactor Resin Speciation

"Experimental Optimization Procedures In The Determination Of Phosphate By Flow Injection Analysis"
Anal. Chim. Acta 1983 Volume 155, Issue 1 Pages 89-102
T. A. H. M. Janse, P. F. A. van der Wiel and G. Kateman

Abstract: Factorial design experiments are used initially to optimize discretely adjustable parameters, viz, injection volume, tube diameter (and hence max. pumping rates), coil lengths and reagent concentration. Then the continuously adjustable parameters, such as pumping rates, are refined by use of the super-modified Simplex procedure. As an example, the determination of PO43- by the molybdenum blue method is optimized and assessed in terms of peak height, peak width, baseline noise and rectilinearity of calibration graphs.
Phosphate Spectrophotometry Computer Optimization Simplex Factorial design Peak width

"Ion-exchange Removal Of Some Interferences On The Determination Of Calcium By Flow Injection Analysis And Atomic Absorption Spectrometry"
Anal. Chim. Acta 1983 Volume 155, Issue 1 Pages 253-257
O. F. Kamson and Alan Townshend

Abstract: Interference by PO43- and SO42- in the cited method for Ca was eliminated by incorporating a column (2 cm x 2.5 mm) of Amberlite IRA-400 or De-Acidite FF (in Cl- form) in the flow system. Interference by 4 mM silicate could be prevented by making the test solution 0.05 to 0.1 M in HF.
Calcium Ion exchange Spectrophotometry Amberlite Interferences Matrix removal Resin

"Determination Of Ammonia In Air And Aqueous Samples With A Gas-sensitive Semiconductor Capacitor"
Anal. Chim. Acta 1984 Volume 164, Issue 1 Pages 127-138
F. Winquist, A. Spetz and I. Lundström, B. Danielsson

Abstract: The properties of a new type of ammonia gas-sensitive semiconductor capacitor are described. The sensor is based on a palladium MOS field-effect capacitor with a thin layer (3 nm) of iridium surrounding the palladium gate. The lower limit of detection for ammonia in air is 1 ppm (0.59 mg kg-1). The analytical characteristics and temperature-dependence of the sensor in measurements of ammonia in air are evaluated. Ammonia in aqueous solutions is determined by the use of a continuous flow system utilizing a gaspermeable membrane in combination with the sensor. The calibration plot of the voltage drop of the capacitor vs. ammonia concentration in 150 µL samples is linear in the concentration range 0.2 x 10^-6-5 x 10^-5 M. Ammonia is determined in rain and river water as well as in whole blood and blood serum; 15 samples per hour can be assayed. Analytical recovery studies and the selectivity properties of the system are described and discussed. Finally, the properties of the flow-through system in continuous monitoring are described.
Ammonia Electrode

"Differential Pulse Voltammetry With Fast Pulse Repetition Times In A Flow Injection System With A Copper-amalgam Electrode"
Anal. Chim. Acta 1984 Volume 166, Issue 1 Pages 119-127
Peter W. Alexander and Umaporn Akapongkul

Abstract: The flow system, equipment and electrodes used have been described previously (Ibid., 1983, 148, 103). Ammoniacal buffer solution (1M), containing 8 mM NaHSO3, was pumped (at 2.8 mL min-1) to a flow-cell containing an amalgamated copper wire as working electrode, a platinum wire as auxiliary electrode and a SCE The sample solution, 0.1 mM Cd(NO3)2 and 0.1 mM Zn(NO3)2 in the buffer were injected through a liquid chromatography septum injector with a hypodermic syringe. With 100-ms repetition times, signal-to-background ratio improved for both voltage scanning and amperometric operation, giving scan rates of up to 100 mV s-1 and detection limits of 0.07 to 0.15 ng of Cd and Zn after de-aeration of sample solution Peak widths were obtained for Cd and Zn at the baseline in the range 12 to 30 s, depending on flow rate, at working potentials of -0.77 and -1.27 V, respectively. The sensitivity of the system was improved by a factor of 10 compared to DC operation, but the selectivity was limited by overlapping peaks or co-deposited metals.
Cadmium Zinc Electrode Voltammetry Peak width

"Extraction-spectrophotometric Determination Of Anionic Surfactants With A Flow Injection System"
Anal. Chim. Acta 1985 Volume 167, Issue 1 Pages 409-412
Yukio Hirai and Katsumaro Tomokuni

Abstract: Anionic surfactants are extracted from aqueous solution into toluene as the ion-pair formed with ethyl violet. Absorbance of the toluene phase is measured at 610 nm. The calibration graph was rectilinear from 0.01 to 1.0 mg L-1 of Na dodecyl sulfate; the coefficient of variation (n = 10) was 2% for 0.5 mg l-1. In the flow injection system, a simple phase converter, located before the injection valve, converts the water stream into a toluene stream. With use of a non-aqueous flow injection system 10 mL of sample can be extracted; 200 mL is required for a separating-funnel method.
Surfactants, anionic Spectrophotometry Sample preparation Extraction Organic phase detection

"Spectrophotometric Determination Of Uranium(VI) With 2-(5-bromo-2-pyridylazo)-5-diethylaminophenol In A Flow Injection System"
Anal. Chim. Acta 1985 Volume 169, Issue 1 Pages 109-115
Elaine Anne Jones

Abstract: The sample was injected into a stream of 2% of cyclohexane-1,2-diamine-NNN'N'-tetra-acetic acid, 0.5% of NaF and 2% of ethanolamine in aqueous ethanol (pH 8.5 to 9.5) and mixed with 0.01% 2-(5-bromo-2-pyridylazo)-5-diethylaminophenol solution in ethanol in a 4-m reaction coil. The absorbance of the complex formed was measured at 578 nm. The calibration graph was rectilinear for 0.5 to 20 mg L-1 of U(VI); the coefficient of variation (n = 12) was 1.9% for 10 mg L-1 of U(VI) in a synthetic leach liquor.
Uranium(VI) Spectrophotometry

"Sequential And Differential Catalytic-fluorimetric Determination Of Manganese And Iron By Flow Injection Analysis"
Anal. Chim. Acta 1985 Volume 169, Issue 1 Pages 141-148
F. Lazaro, M. D. Luque De Castro and M. Valcarcel

Abstract: Two methods for the determination of Mn and Fe in mixtures by flow injection analysis are described, which are based on the catalytic action of Mn or Fe on the oxidation of salicylaldehyde thiosemicarbazone by H2O2. For method(I) a diverting valve is used to select the most appropriate carrier for the determination of one cation in the presence of the other. For method(II) a system with splitting and confluence points is used to obtain two different residence times for the two portions into which the sample is sub-divided. Simplex optimization was used to determine optimum conditions. The calibration graphs were rectilinear for 48 to 200 and 40 to 600 ng mL-1 for methods(I) and(II), respectively.
Manganese Iron Fluorescence Catalysis Optimization Simplex Tecator Sample splitting

"A Kalman Filter For Calibration, Evaluation Of Unknown Samples And Quality Control In Drifting Systems. 4. Flow Injection Analysis"
Anal. Chim. Acta 1985 Volume 174, Issue 1 Pages 27-40
P. C. Thijssen, L. T. M. Prop and G. Kateman, H. C. Smit

Abstract: The application of state estimation in flow injection analysis is described. This method allows the online correction of drift on the calibration graph. The entire calibration system, which is tabulated and summarized, furnishes a set of algorithms for prediction, filtering, evaluation, control, optimization and smoothing. The selection and verification of the calibration model and noise co-variances used were investigated. To demonstrate the applicability of the calculations, an automated flow injection system was used to determine Cl- in aqueous samples, based on the metathesis of SCN- in Hg(SCN)2 by Cl- in the presence of Fe(III) , with measurement of the complex at 470 nm.
Chloride Spectrophotometry Calibration Kalman filter Optimization Theory

"Determination Of Total Chromium By Flow Injection Analysis"
Anal. Chim. Acta 1985 Volume 174, Issue 1 Pages 375-378
M. J. Whitaker

Abstract: The Cr(III) is oxidized to Cr(VI) with Ce(IV) and HNO3 in a reaction coil immersed in a water bath at 80°C, 1,5-diphenylcarbazide is added and the absorbance of the Cr(VI) complex is measured at 540 nm. The peak height varies rectilinearly with Cr concentration. from 0.5 to 10 mg l-1. The mean recovery for ten 5 mg L-1 standards of Cr(III) was 4.96 mg L-1 with a coefficient of variation of 0.8%; for corresponding Cr(VI) standards the corresponding data were 4.94 mg L-1 and 0.61%. Sampling rates were 40 h-1 in both instances. Peristaltic pumping was used, with dual-channel injection. Flow rates for the sample, carrier and reagent streams were 1.2 mL min-1.
Chromium, total Spectrophotometry Heated reaction

"Experimental Comparison Of Flow Injection Analysis And Air-segmented Continuous-flow Analysis"
Anal. Chim. Acta 1986 Volume 179, Issue 1 Pages 189-201
C. J. Patton and S. R. Crouch

Abstract: A miniature continuous-flow analyzer. was used that could be configured to either technique to enable comparison to be made with minimal bias. In the determination of Cl- by its reaction with Hg(SCN)2 in the presence of Fe(III) up to 350 determinations h-1 could be made by either technique. The coefficient of variation were generally <1% at the 15 mg L-1 level (n = 5). The techniques were complementary. The performances of open-tubular, single-bead-string and helical-coil reactors were compared.
Chloride Spectrophotometry Merging zones Method comparison Segmented flow Single bead string reactor

"Preconcentration Of Copper(II) On Immobilized 8-quinolinol In A Flow Injection System With An Ion-selective Electrode Detector"
Anal. Chim. Acta 1986 Volume 179, Issue 1 Pages 509-514
Lars Risinger

Abstract: The cations are bound to the exchanger, containing quinolin-8-ol bound to controlled-pore glass, while the other components pass to waste without contacting the Cu(II)-selective electrode. The bound ions are eluted with 0.5 M HNO3 and the solution is buffered to pH 5.0 with 1 M Na acetate before arrival at the electrode. The recoveries are >95% and the detection limits are 0.1 and 0.03 µM for samples of 5 and 25 ml, respectively.
Copper(II) Electrode Potentiometry Chelation Controlled pore glass Immobilized reagent 8-Hydroxyquinoline Preconcentration

"Sequential Flow Injection Determinations Of Calcium And Magnesium In Waters"
Anal. Chim. Acta 1986 Volume 179, Issue 1 Pages 503-508
J. Alonso and J. Bartroli, J. L. F. C. Lima and A. A. S. C. Machado

Abstract: The solid-state tubular flow-through electrode with PVC membranes described previously (Alegret et al., Ibid., 1984, 164, 147) is used with the sensor - mediator system comprising Ca bis{bis[4-(1,1,3,3-tetramethylbutyl)phenyl] phosphate} and dioctyl phenylphosphonate. The assembly also includes a device for the location of the Orion 90-02-00 double-junction reference electrode. The Ca is measured potentiometrically in the range of 50 µM to 0.1 M and the Mg by air - acetylene flame AAS at up to 10 mg l-1. The coefficient of variation of the electrode response are 1.5% at 0.01 M and 1 mM Ca and 3.5% for 50 µM-Ca (n = 8).
Calcium Magnesium Electrode Electrode Potentiometry Spectrophotometry

"Simultaneous Determination By Iterative Spectrophotometric Detection In A Closed Flow System"
Anal. Chim. Acta 1986 Volume 179, Issue 1 Pages 463-468
A. R&iacute;os, M. D. Luque de Castro and M. Valc&aacute;rcel

Abstract: A flow-injection configuration based on a closed flow system which includes a single spectrophotometric detector and allows iterative detection by passage of the reacting plug n times through the same detector is described. The information obtained can be used in the simultaneous determination of species by kinetic methods. The example given is the simultaneous determination of iron(III) and cobalt(II) via the EGTA/PAR ligand displacement reaction.
Cobalt(II) Iron(III) Spectrophotometry Kinetic Simultaneous analysis Tecator

"Conversion Techniques In Flow Injection Analysis. Determination Of Sulfide By Precipitation With Cadmium Ions And Detection By Atomic Absorption Spectrometry"
Anal. Chim. Acta 1986 Volume 184, Issue 1 Pages 165-172
Bo A. Petersson, Zhaolun Fang, Jaromir Rika and Elo H. Hansen

Abstract: Aqueous solution of Na2S and Cd(NO3)2, both containing ammonium acetate buffer, were injected into the flow injection apparatus (details given), mixed and passed to an ion-exchange column (2.6 cm x 2.5 mm) of quinolin-8-ol azo-immobilized on controlled-pore glass (125 to 177 µm; pore size 50 nm). The pptd. CdS passed through the column and Cd was determined by AAS at 228.8 nm; the excess of Cd(II) was retained and later eluted with 1 M HNO3. Calibration graphs were rectilinear up to 2 mg L-1 of S2-, with a detection limit of 10 µg L-1 and a sampling rate of 100 h-1; the coefficient of variation was 1.2%. Phosphate interfered.
Sulfide Ion exchange Spectrophotometry Controlled pore glass Immobilized reagent Interferences Precipitation 8-Hydroxyquinoline

"Flow Injection Configurations For Chromium Speciation With A Single Spectrophotometric Detector"
Anal. Chim. Acta 1986 Volume 186, Issue 1 Pages 139-146
J. Ruz, A. R&iacute;os, M. D. Luque de Castro and M. Valc&aacute;rcel

Abstract: Sexavalent Cr and total Cr are determined by using the reaction between Cr(VI) and 1,5-diphenylcarbazide (0.17% in 40% ethanol), with UV detection. Tervalent Cr and Cr(VI) are distinguished by using two carrier streams (0.2 M H2SO4), one of which contains 0.5 g L-1 of Ce(IV) in 0.15 M HNO3 to oxidize Cr(III) to Cr(VI) (at 42°C). Calibration graphs are rectilinear over the range 0.2 to 10.0 µg mL-1 of Cr, and the coefficient of variation is 0.8% for 1 µg of Cr. The sampling rate is 40 h-1. The most serious interferents are S2- and Hg(II); NO2-, EDTA, Cu(II) and Mn(II) only interfere in the determination of Cr(III).
Chromium(III) Chromium(VI) Spectrophotometry Heated reaction Interferences Simultaneous analysis Speciation Tecator

"Flow Injection Determination Of Europium After Online Reduction"
Anal. Chim. Acta 1987 Volume 201, Issue 1 Pages 339-343
Kamail H. Al-Sowdani and Alan Townshend

Abstract: The Eu(III) was reduced to Eu(II) in a Jones reductor column (Zn amalgam - 0.1 M HCl) followed by reaction with 0.3 M FeCl3 in citrate buffer, pH 5.2. The Fe(II) formed was complexed with 1,10-phenanthroline and measured at 512 nm, with rectilinear response for up to 200 µg mL-1 of Eu and a limit of detection of 2.5 µg mL-1. The coefficient of variation (n = 11) was 1.56% for 50 µg mL-1. The Eu(II) could also be measured by reaction with Ce(IV) in 0.5 M H2SO4 followed by fluorescence measurement of Ce(III) at 350 nm (excitation at 260 nm). The response was rectilinear for up to 4 µg mL-1 of Eu with a detection limit of 0.2 µg mL-1 and a coefficient of variation (n = 11) of 1.1% for 2 µg mL-1. Tervalent Yb and Sm(III) interfere in both methods.
Europium(3+) Fluorescence Spectrophotometry Interferences Jones reductor Reduction column

"Flow Injection Spectrophotometric Determination Of Silicate, Phosphate, And Arsenate With Online Column Separation"
Anal. Chim. Acta 1988 Volume 204, Issue 1-2 Pages 53-62
Yoshio Narusawa

Abstract: Sample solution (300 µL) was injected into the carrier stream of KCl - aqueous NH3 - EDTA (0.75 mL min-1) and passed through an anion-exchange column (15 cm x 4.6 mm) of TSK-gel SAX (5 µm). The sample was mixed with (NH4)6Mo7O24 solution and passed through a reaction coil at 95°C, then mixed with a stream (0.25 mL min-1) of ascorbic acid solution before being passed through a second coil at 95°C. The absorbance was measured at 810 nm. Calibration graphs were rectilinear from 0.01 to 0.25 mM. The relative retention times depended on the concentration. of the eluting solution The separation and simultaneous determination of SiO32-, PO43- and AsO43- was satisfactory at ~0.1 mM concentration. of each ion.
Silicate Phosphate Arsenate ion Ion exchange Spectrophotometry Heated reaction

"Criterion For Quantifying The Reliability Of Analytical Results In Method Development And Evaluation"
Anal. Chim. Acta 1988 Volume 207, Issue 1-2 Pages 111-123
R. Wolters and G. Kateman

Abstract: The reliability of analytical results is quantified in a single measure, the max. total error, which comprises both the bias and precision, and takes account of the statistical uncertainty of these estimates. It can be used as a criterion by the analyst when selecting a method. The applicability of the procedure in method development and evaluation is illustrated by the flow injection determination of PO43- in water.
Phosphate Theory

"Flow Injection Techniques For The Removal Of Stable-compound Interferences In Flame Atomic Absorption Spectrometry Of Calcium"
Anal. Chim. Acta 1988 Volume 214, Issue 1-2 Pages 339-347
C. E. Adeeyinwo and J. F. Tyson

Abstract: Interference from PO43- in the determination of Ca was reduced by optimization of the position of the capillary tip in relation to the oxidant inlet in the nebulizer and of the instrument operating parameters. However, interference from Al had to be removed by incorporating a separation procedure and devising a merging stream manifold. The sample was injected into the water carrier stream, which then merged with the reagent stream (NH3 - ammonium oxalate). The pptd. Ca oxalate was retained in a column containing glass beads (0.5 mm diameter) and a nylon filter, and then eluted with HCl for AAS determination. Up to 200 mg L-1 of Al was tolerated with a coefficient of variation of 2% for Ca at the 10 mg L-1 level.
Calcium Spectrophotometry Glass beads Interferences Merging zones Precipitation Optimization

"Flow Injection Spectrophotometric Determination Of Fluoride By Using The Zirconium/alizarin Red S Complex"
Anal. Chim. Acta 1988 Volume 214, Issue 1-2 Pages 433-438
T. J. Cardwell, R. W. Cattrall and M. Mitri, I. C. Hamilton

Abstract: Two flow injection manifolds, viz, the Chemifolds I and II, were used for determination of F- based on the decrease in absorbance at 520 nm of the Zr - C. I. Mordant Red 3(I) complex caused by the presence of F-. Sample was injected into the carrier stream (H2O at 1.2 mL min-1) and then mixed with the two reagent solution (1.15 mM zirconyl chloride in 0.55 M HCl - 0.2 M H2SO4 and 2.3 mM I) in a 600-mm reaction coil. The solution then passed to the flow cell for detection of the colored complex. The calibration graph was rectilinear for 0.1 to 10 mg L-1 of F- with a coefficient of variation of 2.2%. Aluminum, Fe(III) and PO43- interfered.
Fluoride Spectrophotometry Computer Interferences

"Flow Injection Determination Of Organic Contaminants In Water Using An Ultraviolet-mediated Titanium Dioxide Film Reactor"
Anal. Chim. Acta 1990 Volume 231, Issue 1 Pages 13-20
Gary K. -C. Low and R. W. Matthews

Abstract: A miniature spiral reactor was constructed by immobilizing a thin film of TiO2 on the inner surface of a length of PTFE tubing, then wrapping the treated tubing around a near-UV illuminating source. The reactor was installed after the injection port of a flow injection system; a diagram is presented of a second injection port, mounted in parallel, with the first, for the introduction of CO2 for calibration. Organic solutes in aqueous solution flowing along the tube were oxidized photocatalytically to CO2 that was then detected by conductivity. The effects of temp., flow rate, reactor length, O concentration. and catalyst loading are discussed. The technique was applied to the determination of alcohols, formaldehyde, oxiran and single-cell alga in sterile water for medical use. The detection limits were 10 nM-methanol and 15 nM-formaldehyde for an injection volume of 20 µL and a flow rate of 3 mL min-1. The coefficient of variation (n = 12) for 8 µM-methanol was 1.5%.
Methanol Formaldehyde Conductometry Calibration Photochemistry Catalysis Detection limit Optimization

"Segmental Flow Injection Analysis: Device And Applications"
Anal. Chim. Acta 1990 Volume 238, Issue 1 Pages 183-190
Li-Ching Tian, Xiao-Ping Sun, Yi-Yun Xu and Zheng-Liang Zhi

Abstract: The cited system possesses features of both flow injection and continuous-flow analysis. The sample zone is segmented by only two air bubbles and contained a valve designed so that sample and bubbles could be quantitatively injected into the carrier stream. The system provided residence times of >10 min at temperature up to 95°C without loss of peak height or sampling frequency, and owing to good reproducibility, analysis could be carried out before the equilibrium state was reached. The method was demonstrated by the determination of amino-acids in tea with the ninhydrin reagent, giving recoveries from 97 to 106%, a limit of detection of 5 mg L-1 and a coefficient of variation (n = 3) of 2.8%. Other applications included determination of ammonium and V in water, Cu in ores and creatine in urine.
Ammonium Vanadium Copper Creatine Detection limit

"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 Automation Column Interferences Preconcentration

"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 Spectrophotometry Column Preconcentration Chelex

"Fluorimetric Determination Of Boron With Chromotropic Acid By Flow Injection Analysis"
Anal. Chim. Acta 1991 Volume 251, Issue 1-2 Pages 269-274
S. Motomizu*, M. Oshima and Z. Jun

Abstract: Three flow injection systems were evaluated for the cited determination. The best results were obtained with the system in which sample solution (200 µL) was injected into water (carrier stream; flow rate 0.4 mL min-1), the stream was merged with 0.25 mM chromotropic acid (reagent stream) and allowed to react in a 2-m PTFE reaction coil before being merged with 0.5 M NaOH and passed to a spectrofluorimeter. Fluorimetric detection was at 350-360 (excitation at 313 nm). With this system a sample pH of 2 to 12 was tolerated. The calibration graph was rectilinear from 0.5 nM to 0.1 mM B(OH)3. The detection limit was 5 nM-B. The sampling rate was 60 h-1. Tolerated concentration. of ions normally present in water are tabulated. The method was applied to water samples.
Boron Fluorescence pH

"Determination Of Microgram And Nanogram Amounts Of Active Chlorine In Water By Iodine - Azide Reaction Induced By Thiosulfate Or Thioammeline"
Anal. Chim. Acta 1991 Volume 252, Issue 1-2 Pages 127-132
Jan Kurzawa*, Zbigniew Kurzawa and Krystyna Janowicz

Abstract: An indirect determination of active Cl in water is described based on the iodine - azide reaction and measuring the amount of thiosulfate (I) or thioammeline (II) oxidized by Cl is described. Three methods based on this principle were applied, viz, back-titration of excess iodine, titration with an iodine reagent and continuous-flow amperometric detection of the released iodine. The working ranges for the determination of Cl by back-titration were 0.2 to 2.4 and 0.02 to 0.14 µg mL-1 in the presence of I and II, respectively, by titration were 0.3 to 2 ng mL-1 in the presence of II and by continuous-flow determination were 0.5 to 5 µg L-1 and 0.05 to 1.5 mg L-1 depending on the reaction conditions and inductor used.
Chlorine, active Amperometry Titrations

"Adsorptive Stripping Voltammetry On Mercury-coated Carbon-fibre Ultra-micro-electrodes"
Anal. Chim. Acta 1993 Volume 273, Issue 1-2 Pages 101-109
J. Amez del Pozo, A. Costa Garc&iacute;a and P. Tu&ntilde;&oacute;n Blanco*

Abstract: The ultra-micro-electrodes were prepared by sealing a 2-cm length of 7.5 µm diameter carbon fiber into a 100 µL micropipette, a 0.5-mm length of the fiber being permitted to project from the micropipette tip; Hg and Cu wire were used for electrical contact. After being cleaned with chromic acid and HNO3 such a micro-electrode was used to determine mitozantrone (I) by immersion in a solution of I in 0.1 M HClO4 containing 0.1 mM Hg(II), which was electro-deposited on the electrode for 60 s at -1.2 V vs. Ag/AgCl. The potential was then held at -0.2 V for, e.g., 3 s before I was determined by phase-selective a.c. voltammetry at 75 Hz with a superimposed voltage amplitude of 25 mV and a detection angle of 90°C. Calibration graphs were rectilinear from 0.5 (detection limit) to 20 nM-I. In the determination of 5 nM-I the RSD was 5.05% (n = 10). In the determination of 10 nM-I there was little or no interference from surfactants, e.g., SDS. Procedures for the determination of I in urine and of folic acid in aqueous solution are also described. Such electrodes, which could be used for 1 to 2 months without loss in sensitivity, might be useful in flow injection analysis or LC.
Mitozantrone Folic acid Voltammetry Electrode Electrode Interferences

"Rapid Microwave-assisted Hydrolysis Of Formetanate"
Anal. Chim. Acta 1993 Volume 281, Issue 2 Pages 249-257
K. Dema-Khalaf, A. Morales-Rubio and M. de la Guardia

Abstract: A portion (0.02 g) of formetanate hydrochloride (I) was dissolved in water and diluted to 100 mL. Portions of this stock solution were treated with NaOH solution (of varying concentration.) with microwave heating, at various power levels, for 1-7 min. After digestion, the digests were diluted to 25 mL with water. Portions (100 µL) of the treated samples were injected into a carrier stream of water which was merged with a stream of 0.05 M NaOH in a reaction coil and this stream was then mixed in another reaction coil with a solution containing p-aminophenol (115 µg/ml) and potassium metaperiodate. The absorbance of the blue dye formed was measured at 576 nm. I was found to be quantitatively hydrolyzed with 0.1 M NaOH in 150 s in a sealed PTFE reactor and at a radiation power of 390 W. The microwave assisted procedure was 16 times faster than the classical thermal hydrolysis procedure at 90°C. The method was applied in the analysis of water samples. The detection limit was 0.025 mg/l of I. The RSD (n = 5) was 0.5% for 6 mg/l of I.
Formetanate hydrochloride Sample preparation Spectrophotometry

"Amperometric Enzyme Electrodes For Lactate And Glucose Determinations In Highly Diluted And Undiluted Media"
Anal. Chim. Acta 1993 Volume 281, Issue 3 Pages 489-502
Dorothea Pfeiffer, Frieder W. Scheller and Karen Setz, Florian Schubert

Abstract: The combination of immobilized enzymes and amperometric electrodes to realize lactate and glucose probes for application to real samples is described. The paper concentrates on the design of lactate oxidase and glucose oxidase membranes for sensors in different areas of diagnostic relevance. Two types of membranes based on the same enzyme immobilization but characterized by different diffusion characteristics are presented. [References: 25]
Glucose Lactate Amperometry Electrode Sensor Interferences Immobilized enzyme

"Flow Injection Chemiluminescence Determination Of Cobalt(II) And Manganese(II)"
Anal. Chim. Acta 1993 Volume 283, Issue 1 Pages 379-385
Qingxiong Lin, Alfonso Guira&uacute;m and Rosario Escobar*, Francisco F. de la Rosa

Abstract: A diagram is given of a flow injection system in which the aqueous sample solution was treated with a pre-mixed solution of luminol and KIO4 and passed through a coil of transparent PTFE tubing (1 mm i.d.) forming the flow cell. The light intensity was monitored by a photomultiplier tube. The optimum pH for the analysis was 12.9 using 0.3 mM KIO4 and 1 mM luminol. In the determination of Mn(II) 10 µM-quinolin-8-ol was used to mask Co(II); 5 mM sodium citrate was used as masking agent for foreign ions in the simultaneous determination of Co and Mn. In the presence of quinolin-8-ol, the log-log calibration graph was linear for 0.02-9 ng/ml of Mn; with citrate as masking agent, the linear ranges were 0.01-12 ng/ml for Co and 0.06-7 ng/ml for Mn. Limits of detection were 0.02 and 0.01 ng/ml for Mn and Co, respectively, and the RSD for 1 ng/ml of Co and Mn was 4.3 and 2.1%, respectively (n = 15). The method was used to determine Mn(II) in water samples to which 0.3 mM H3PO4 had been added, and for the determination of Co and Mn in water in the presence of 5 mM citrate. Cobalt was also determined in vitamin B12 after liberating the Co by acidification.
Cobalt(II) Manganese(II) Chemiluminescence 8-Hydroxyquinoline

"Determination Of Paraquat By Flow Injection Spectrophotometry"
Anal. Chim. Acta 1993 Volume 284, Issue 2 Pages 275-279
Archana Jain, Krishna K. Verma and Alan Townshend*

Abstract: The cited method is based on the reduction of paraquat (I) to a blue radical cation by dehydroascorbic acid (produced by oxidizing ascorbic acid with potassium iodate). Samples (75 µL) were injected into a stream (1.1 ml/min) of water which merged with streams of 1 M NaOH and of 15 mM ascorbic acid containing 0.5 mM potassium iodate and 0.1% EDTA (0.3 and 0.6 ml/min, respectively) which had been pre-mixed in a 50 cm mixing coil. The merged streams then passed through a reaction coil (75 cm x 0.5 mm i.d.) maintained at 60°C, to a spectrophotometer where the absorbance was measured at 600 nm. The calibration graph was linear from 0.1-100 µg/ml of I and the detection limit was 20 ng/ml; the RSD (n = 6) were 1-2.5% (for 0.1-60 µg/ml of I). A large number of tested compounds (anions, metal ions and other pesticides) did not interfere; interference by diquat was masked with NaOH. The method was applied to potable water.
Paraquat Endothall sodium Spectrophotometry Heated reaction Interferences Linear dynamic range

"Comparison Of Mixing Devices For Flow Injection Determinations Based On Doublet Peak Formation"
Anal. Chim. Acta 1994 Volume 286, Issue 2 Pages 169-178
Roger T. Echols and Julian F. Tyson*

Abstract: A variety of static tubular mixing devices (both column and open tubular) were examined for use within time-based FIA. The comparison was based on the well-stirred tank model which accurately describes the separation of flow injection doublet peaks. The complexation of lanthanum chloride in 5 mM acetate buffer of pH 6.2 with 0.3 µM-methyl thymol blue was used as a model reaction, with UV detection at 608 nm. The best mixing device consisted of 3/16 in. plastic helical segments inserted into lengths (384-1860 µL volume) of 6 mm i.d. tubing, with flow rates of 18-39 µL/s. Plots of doublet-peak separation vs. the natural log. of La(III) concentration were linear from 0.0114-11.3 mM La(III). Applications of the mixer device to the FIA of Zn and methyl thymol blue complexation, NaOH/HCl acid-base neutralization, and Mg/Ca water hardness determination using EDTA with a calmagite indicator are discussed.
Zinc Magnesium Calcium Spectrophotometry

"Mercury(II) Acetate-Nafion Modified Electrode For Anodic-stripping Voltammetry Of Lead And Copper With Flow Injection Analysis"
Anal. Chim. Acta 1994 Volume 291, Issue 1-2 Pages 81-87
Ruelito R. Dalangin and Hari Gunasingham*

Abstract: Ethanolic solution of mercury(II) acetate and Nafion perfluorosulfonate resin were mixed and used to coat the polished vitreous carbon electrode surface. The modified electrode was used in the flow injection determination of trace metals using a wall-jet detector. The wall-jet cell was filled with supporting electrolyte at ~1.2 ml/min and once all three electrodes were submerged, the pump was switched off and a potential of -1.0 V was applied for 5 min. The electrolyte flow was started up again at ~1.5 ml/min and the potentials were held at 0.0 V for 2 min. Sample was delivered to the cell for 45 s and a hold time of 15 s was observed before stripping the metals in stationary solution at 20 mV/s. The effects of Hg loading, Nafion loading, pH, flow rate, electrode-inlet distance and the presence of organic surfactants was studied (discussed). The method was applied to the determination of Pb2+ (0.07-2.8 µg/ml) and Cu2+ (0.5-2.3 µg/ml) in industrial effluents; detection limits were 5 and 4 ng/ml, respectively. RSD for the determination of 0.483 µM-Pb and 1.57 µM-Cu were 7.16 and 8.10%, respectively.
Lead(2+) Copper(II) Voltammetry Electrode

"Determination Of Copper In Water And Rice Samples By Flame Atomic Absorption Spectrometry With Flow Injection Online Adsorption Preconcentration Using A Knotted Reactor"
Anal. Chim. Acta 1994 Volume 298, Issue 2 Pages 167-173
Hengwu Chen, Shukun Xu and Zhaolun Fang

Abstract: A flow-injection on-line adsorption pre-concentration flame atomic absorption spectrometric system for the determination of copper was developed. The copper diethyldithiocarbarmate ehelate was adsorbed on the walls of a PTFE knotted reactor. The sorbed species was eluted by isobutyl methyl ketone at a flow-rate of 4.1 mL min-1. Air segmentation between sample and eluent was employed to avoid mixing of the neighbouring phases under fast elution rates. An enhancement factor of 120 and a detection limit of 0.2 µg L-1 Cu were achieved for a 60 s loading period (sample throughput 46 h-1). The relative standard deviations were 1.7% and 3.6% at the 20 µg L-1 and 2 µg L-1 Cu levels, respectively. Interference from at least 50 µg L-1 Fe(III) was eliminated by adding ascorbic acid. The method has been applied successfully to determine µg L-1 amounts of copper in drinking water and sea water and Ju µg-1 amounts of copper in rice.
Copper Spectrophotometry Preconcentration Knotted reactor

"Flow Injection Chemiluminescence Determination Of Ultra Low Concentrations Of Nitrite In Water"
Anal. Chim. Acta 1995 Volume 316, Issue 2 Pages 261-268
Pavel Mikuska*, Zbynk Veea and Zbynk Zdrhal

Abstract: A new flow chemiluminescence method for the determination of ultra low concentrations of nitrite in water is presented. Nitrite reacts with H-2O-2 in acid medium to form peroxynitrous acid that is subsequently detected as peroxynitrite by the chemiluminescence reaction with alkaline solution of luminol. The detection limit of nitrite is 1 times 10^-9 mol L-1 (for 50 µl samples) and the calibration graph is linear up to 1 times 10^-5 M NO-2-. The relative standard deviations for 1 times 10^-6 M and 3 times 10^-8 M NO-2- are 1.8% and 5.4%, respectively. The interferences of cations are eliminated by passing the sample through a cation-exchange column. Common anions do not interfere. Analysis time is 3 minutes. The results are in good agreement with a standard spectrophotometric method. (39 References)
Nitrite Chemiluminescence Interferences Method comparison

"Chemiluminescence Flow System For The Monitoring Of Chromium(VI) In Water"
Anal. Chim. Acta 1995 Volume 318, Issue 1 Pages 71-76
Zhujun Zhang*, Wei Qin and Shuna Liu

Abstract: A novel chemiluminescence(CL) system has been developed for determining chromium(VI) in water. The analytical reagents involved in the CL reaction, including luminol and hexacyanoferrate(II) were both immobilized on an anion exchange resin column. While a volume of sodium phosphate was passed through the column, these two reagents were eluted from the resins and then mixed with a chromium(VI) stream containing hydrochloric acid. By the fast oxidation reaction between chromium(VI) and hexacyanoferrate(II), hexacyanoferrate(III) was generated, which then reacted with luminol in alkaline aqueous solution to produce CL. The CL emission intensity was correlated with the chromium(VI) concentration in the range 4 x 10^-8 to 1 x 10^-6 g ml-1, and the detection limit was 1.4 x 10^-8 g ml-1 chromium(VI). Interfering metal ions present in water were effectively separated by a pre-column cation exchanger. A complete analysis, including sampling and washing, could be performed in 1 min with a relative standard deviation of less than 5%. The system was stable for over 200 analyzes and has been applied successfully to the determination of chromium(VT) in water samples.
Chromium(VI) Chemiluminescence

"Automated Trace Enrichment And Determination Of Metals Using A Combination Of Supported Liquid Membrane For Sample Pretreatment And Graphite-furnace Atomic Absorption Spectrometry For The Determination"
Anal. Chim. Acta 1996 Volume 327, Issue 3 Pages 295-300
F. Malcus, N. -K. Djane, L. Mathiasson* and G. Johansson

Abstract: A computer controlled system has been developed for automated trace analysis for metals. The system used consists of four parallel supported liquid membrane devices for analyte enrichment, leaving an efficiently cleaned and enriched sample in the acceptor for the final analytical step, which is performed by graphite furnace atomic absorption spectrometry (AAS). The system was tested with 40% di(2-ethylhexyl)phosphate in kerosene as the liquid in the porous membrane and with the model metals Al, Cd and Cu at concentrations below µg/l. The average relative standard deviation (RSD) was 6.5% at 0.5 µg/l and 6.3% at 1.0 µg/l based on 108 independent measurements. The blank for Al, which is the most difficult metal to determine with respect to contamination was 0.15 µg/l with an average RSD (n=16) of 11%. Using a 30 min period for processing the samples in the supported liquid membrane step, the sample throughput was eight samples per hour.
Trace elements Spectrophotometry Supported liquid membrane Preconcentration Computer Automation

"Chemiluminescence Arising From The Oxidation Of Bilirubin In Aqueous Media"
Anal. Chim. Acta 1996 Volume 333, Issue 3 Pages 267-275
L. P. Palilisa, A. C. Calokerinosa,*, and N. Grekasb

Abstract: The chemiluminescence reactions of aqueous alkaline solutions of bilirubin with NaOCl and N-bromosuccinimide (I) were studied in batch and flow systems. The effects of alkali and oxidant concentrations and flow rates were examined to optimize the emission intensity. The batch and continuous-flow measurement of bilirubin with NaOCl both required initial oxidant and alkali concentrations of 0.1 and 0.08M, respectively. Using I, the oxidant concentration was 0.045 M but the alkali concentration required was 1 M by the batch process and 4 M by FIA. The detection limits were 0.05 µg/ml with NaOCl and 0.075 or 1.75 µg/ml with I by the batch or FIA procedures, respectively. The linear ranges varied from 0.1-4 to 2-50 µg/ml and the RSD were 1.4-3.2% (n = 8 or 11). There was severe interference from albumin.
Bilirubin Chemiluminescence Interferences

"Design And Construction Of A Flow System For Determination Of Copper(II) Ions In Water By Means Of A Chemically Modified Carbon Paste Electrode"
Anal. Chim. Acta 1996 Volume 335, Issue 3 Pages 275-282
A. Safavi*, M. Pakniat and N. Maleki

Abstract: Copper(II) pre-concentration was studied by means of a carbon paste electrode modified with 1,2-bismethyl (2-aminocyclopentene-carbodithioate)ethane. A flow system was designed and constructed for reproducible pre-concentration and subsequent determination of Cu(II) (≤ 2 x 10^-4M) accumulated by differential pulse polarography. Effects of different parameters on the peak area were studied. Rapid and convenient acid renewal allows use of a single modified electrode in multiple analytical determinations. For six accumulation/measurement/renewal cycles, relative standard deviation was 2.9%. As little as 1.4 x 10^-6 M Cu(II) in water can be determined (4 min pre-concentration time). The performance of the electrode is free from most potential interferers.
Copper(II) Electrode Electrode

"Assessing The Validity Of Principal-component Regression Models In Different Analytical Conditions"
Anal. Chim. Acta 1997 Volume 337, Issue 3 Pages 287-296
A. Rius*, M. P. Callao, J. Ferr&eacute; and F. X. Rius

Abstract: A methodology was proposed for checking the validity of a principal component regression model when the experimental conditions had changed from those existing during the development of the model. The method was based on re-measuring a subset of the sample set that had been used to construct the model and assessing the trueness and precision of the results by statistical techniques. The approach was evaluated using a simulated data set and also experimental data for the determination of various analytes in water by sequential injection spectrophotometric analysis. This study proposes a methodology for assessing the validity of principal component regression models when the experimental conditions which have been used in the process of modeling may have changed. The methodology proposed is based on the procedure for selecting the validation sample subset which includes the D-optimal criterion and application of Fedorov's exchange algorithm. Two basic performance characteristics define the validity of the models: trueness is assessed by linear regression using the joint confidence test for the slope, and the intercept and precision is estimated by bias corrected MSEP and RRMSEP. The methodology is validated with a simulated data set and three real data sets corresponding to models constructed for spectrophotometric data from determinations of various analytes in waters using sequential injection analysis (SIA). Using a reduced number of samples can be very useful in several applications, such as in process analysis control, and is especially useful as an initial step to check the need for standardization.
Spectrophotometry Sequential injection Principal component analysis Modeling Chemometrics

"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 Immunoassay Fluorescence Column Detection limit Immobilized enzyme Method comparison Selectivity

"Figures Of Merit In Multivariate Calibration. Determination Of Four Pesticides In Water By Flow Injection Analysis And Spectrophotometric Detection"
Anal. Chim. Acta 1997 Volume 348, Issue 1-3 Pages 167-175
J. Ferr&eacute;, R. Boqu&eacute;, B. Fern&aacute;ndez-Band, M. S. Larrechi*, and F. X. Rius

Abstract: The accuracy, trueness and determination limit of a flow injection analysis (FIA) method are evaluated in the simultaneous determination of the pesticides Carbaryl (RYL), Carbofurane (CBF), Propoxur (PPX) and Isoprocarb (IPC) in water by multicomponent analysis. Calibration is based both on the spectra of artificially made samples according to the experimental design theory and the spectra of pure pesticides. Prediction errors in the range 0.1-1.4 evaluated as RMSEP are obtained. The absence of bias is evaluated from the joint confidence interval test for the regression line obtained from measured and predicted concentrations taking into account errors in both axes. Multivariate determination limits were found to be between 0.03 and 1.0 ppm.
Pesticides Spectrophotometry Multivariate calibration

"Rapid Flow Injection Analysis Method For Successive Determination Of Ammonia, Nitrite, And Nitrate In Water By Gas-phase Chemiluminescence"
Anal. Chim. Acta 1997 Volume 349, Issue 1-3 Pages 11-16
Toyoaki Aoki* Shinji Fukuda, Yasuo Hosoi and Hiroshi Mukai

Abstract: A flow injection analysis method is presented in which an aqueous sample itself is used as the carrier stream and reagents are injected into this sample stream. Nitrite and nitrate were converted into nitric oxide (NO) in acidic media using iodide and titanium(III) as reducing agents, respectively. Ammonia was reacted with hypochlorite to generate a volatile compound. The NO or the volatile compound was transferred into air in a glass-tube separator and the volatile compound was subsequently converted into NO by combustion at 600°C. The NO was then reacted with ozone and the resulting chemiluminescence was detected. The determination limit was 1 x 10^-8 M for ammonia and nitrate, and was 1 x 10^-8 M for nitrite. The total time for the analysis of ammonia, nitrite, and nitrate in one sample was less than 3 min.
Ammonia Nitrate Nitrite Chemiluminescence Gas phase detection

"Membrane Introduction Mass-spectrometry"
Anal. Chim. Acta 1997 Volume 350, Issue 3 Pages 257-271
N. Srinivasan, R. C. Johnson, N. Kasthurikrishnan, P. Wong and R. G. Cooks*

Abstract: An overview of membrane introduction mass spectrometry (MIMS) is presented and comparisons are made with other direct sample introduction techniques. Special attention is given to the unique advantages and the limitations of newer variants on the MIMS technique, including affinity MIMS, reverse-phase and trap MIMS. The salient features of the interfaces used in MIMS are summarized and the various membrane materials commonly used are delineated. The applicability of MIMS is illustrated via discussion of (i) bioreactor monitoring (represented by yeast fermentation), (ii) environmental monitoring (illustrated by analysis of contaminated ground water samples) and (iii) online chemical reaction monitoring (exemplified by the photolysis of aryl esters). The applicability of MIMS to the analysis of environmental samples, including complex mixtures in water, air and soil, is noted. 77 References
Mass spectrometry Membrane Process monitoring Photochemistry Review

"Flow Injection Online Coprecipitation-preconcentration System Using Copper(II) Diethyldithiocarbamate As Carrier For Flame Atomic Absorption Spectrometric Determination Of Cadmium, Lead And Nickel In Environmental-samples"
Anal. Chim. Acta 1997 Volume 353, Issue 2-3 Pages 181-188
Hengwu Chen*, Jincao Jin and Yufeng Wang

Abstract: A novel flow injection (FI) online coprecipitation-pre-concentration system with diethyldithiocarbamate (DDTC) Copper(LI) being used as a carrier for the flame atomic absorption spectrometric determination of trace cadmium, lead and nickel was developed. Sample solutions, spiked with 120 µg mL-1 Cu2+ and acidified to 0.5 M with hydrochloric acid, were merged online with a 2.1% DDTC solution in a 'T' connector upstream of a knotted reactor. The analytes were coprecipitated with DDTC-Cu2+ and collected on the inner wall of the knotted reactor. The collected species were eluted with isobutyl methyl ketone, and the effluent was transported directly into the nebulizer. Enhancement factors of 26, 45 and 22 were obtained for cadmium, lead and nickel, respectively with a loading period of 30 s. The detection limits (3s) for cadmium, lead and nickel were 0.23, 3.2 and 1.4 µg L-1 respectively, and the relative standard deviations (n=10) were 1.4% for 20 g L-1 cadmium, 2.0% for 200 µg L-1 lead and 2.2% for 80 µg L-1 nickel. At least 50 mg L-1 of such metal ions as Fe3+, Al3+, Mn2+, Zn2+ and Co2+, and 30 mg L-1 of Cu2+ could be tolerated. The method has been successfully applied to the determination of trace cadmium, lead and nickel in various water samples and a standard reference soil. 18 References
Cadmium Lead Nickel Spectrophotometry Preconcentration Coprecipitation Interferences Reference material Knotted reactor MIBK Diethyldithiocarbamate

"Improvement On Simultaneous Determination Of Chromium Species In Aqueous-solution By Ion Chromatography And Chemiluminescence Detection"
Anal. Chim. Acta 1997 Volume 354, Issue 1-3 Pages 107-113
Bente Gammelgaarda,*, Yi-ping Liaob and Ole J&oslash;nsa

Abstract: A sensitive method for the simultaneous determination of chromium(III) and chromium(VI) was chromatography and chemiluminescence detection. Two Dionex ion-exchange guard columns in series, CG5 and AG7, were used to separate chromium(III) from chromium(VI). Chromium(VI) was reduced by potassium sulfite, whereupon both species were detected by use of the luminol-hydrogen peroxide chemiluminescence system. Parameters affecting retention times and resolution of the separator columns, such as eluent pH, eluent composition, reductant pH and concentration, and flow rates were optimized. Furthermore, the stabilities of reductant and luminol solutions were studied. The linear range of the calibration curve for chromium(III) and chromium(VI) was 1-400 µg L-1. The detection limit was 0.12 µg L-1 for chromium(III) and 0.09 µg L-1 for chromium(VI), respectively. The precision at the 20 µg L-1 level was 1.4% for chromium(III) and 2.5% for chromium(VI), respectively. The accuracy of the chromium(III) determination was determined by analysis of the NIST standard reference material 1643 c, Trace elements in water with the result 19.1±1.0 µg Cr(III) L-1 (certified value 19.0±0.6 µg Cr(III) l-1). The method was applied to analyze the stability of chromium patches for contact dermatitis testing. 19 References
Chromium(III) Chromium(VI) Chemiluminescence HPIC Detection limit Optimization Post-column derivatization Precision Preconcentration Speciation Reference material

"Magnesium Ion-selective Electrode Optimization And Flow Injection Analysis Application"
Anal. Chim. Acta 1997 Volume 356, Issue 1 Pages 105-111
Nikolas A. Chaniotakisa,*, John K. Tsagatakisa, Elizabeth A. Moschoua, Steven J. Westb and Xiaowen Wenb

Abstract: The development of manual and Flow Injection Analysis (FIA) methods for the determination of magnesium in aqueous samples by means of a magnesium ion-selective electrode (ISE) is described. A sample pre-treatment solution containing pH buffering compounds and alkaline earth metal complexing agents was developed to minimize interferences and optimize the limits of detection. For the achievement of the desired potential stability of the electrode in the FIA mode, a pulseless syringe pump was employed to eliminate the possibility of a variable streaming potential. This, in conjunction with a laminar flow cell with low and well-controlled dead volume allowed for the simple, semi-automatic, direct, inexpensive, and accurate determination of magnesium in water samples. Results from both the manual and FIA method were corroborated by capillary electrophoresis (CE) and Atomic Absorption Spectroscopy (AAS). 16 References
Magnesium(II) Electrode Potentiometry Optimization Buffer Complexation Interferences Method comparison

"Application Of Differential Electrolytic Potentiometry For Detection In Flow Injection Analysis"
Anal. Chim. Acta 1998 Volume 360, Issue 1-3 Pages 195-201
A. M. S. Abdennabi*, M. E. Koken and M. M. Khaled

Abstract: The applicability of differential electrolytic potentiometry as a detection system in flow injection analysis is studied. A computer-controlled injector which delivers precise volumes of sample solutions in a reproducible manner was developed. Conditions such as c.d., concentrations. of the solutions, and the flow rate were optimized. Chloride in water was determined by this system. The relation between chloride concentration. and the measured signal was Nernstian for concentrations. >6 µg Cl-/mL. For solutions below this concentration, the relation is linear.
Chloride Potentiometry Electrode Optimization Computer

"Online Separation And Spectrophotometric Determination Of Low Levels Of Aluminum In High-salt Content Samples: Application To Analysis Of Hemodialysis Fluids"
Anal. Chim. Acta 1998 Volume 362, Issue 2-3 Pages 163-169
Denise Bohrer*, Adriana Gioda, Regina Binotto and Paulo C&iacute;cero do Nascimento

Abstract: An online pre-concentration and matrix separation procedure for the spectrophotometric determination of low levels of aluminum in aqueous and high-salt content matrices was developed. Aluminum was pre-concentrated on polyethylene powder as a complex with Chrome azurol S and, after elution, the complex was spectrophotometrically determined, without interference of the matrix. The assayed salts were sodium, potassium, magnesium and calcium chlorides and sodium acetate, usually employed in hemodialysis fluids. A polyethylene powder column was incorporated to the flow system by using a microcolumn as the loop of a six-port valve connected to an injector and to the spectrophotometric detector. Effects of eluent composition and concentration, reactor length and influence of the presence of salts on the pre-concentration and elution steps were investigated. The proposed method was characterized by a precision of about 90% and a detection limit of 17 ng Al (6 x 10^-10 mol). Recoveries from spiked samples of the salts were between 87-110%, and results were in agreement with determinations by graphite furnace atomic absorption spectrometry. The method was applied to the analysis of saline concentrates and water for hemodialysis.
Aluminum Spectrophotometry Preconcentration Dialysis Preconcentration Complexation Interferences Method comparison

"Real-time Simplex Optimization Of Flow Injection Systems For Chemical Analysis"
Anal. Chim. Acta 1998 Volume 366, Issue 1-3 Pages 313-318
Maria Fernanda Gin&eacute;*, Robinson L. Tuon, Andr&eacute; A. Cesta, Ana Paula Packer and Boaventura F. Reis

Abstract: A computer controlled flow injection system was assembled to implement a real-time simplex algorithm. Two experimental variables, flow rate and sample:reagent ratio were controlled by a fully automated manifold. A computer interface was programmed to command the pumping speed, introduction of sample:reagent amounts by solenoid valves, on-time data acquisition, and examn. of detector responses for application of the simplex algorithm. The feasibility of the approach was assessed by optimizing the flow parameters for Cl- determination in water with different analyte concentrations Optimum experimental conditions for 5.00, 25.0, 50.0, and 100 mg/L Cl- were maintained. A precision characterized by a relative standard deviation <1% and a sample throughput of 120/h were attained.
Chloride Spectrophotometry Simplex Optimization Powell Computer Automation

"Determination Of Vanadium(V) By A Kinetic Stopped-flow FIA Method With Spectrophotometric Detection"
Anal. Chim. Acta 1998 Volume 366, Issue 1-3 Pages 287-293
M. E. Palomeque, A. G. Lista and B. S. Fern&aacute;ndez Band*

Abstract: Two automated methods to determine V5+ in water are described. A continuous-flow system based on the classical reaction for V5+ determination with 3,3'dimethylnaphtidine in acid medium using a stopped-flow technique and spectrophotometric detection was developed (Method A). It was possible to increase reaction kinetics to obtain a higher sample throughput (34/h), lower detection limits (0.2 mg/L), and high sensitivity. To determine still a lower V5+ concentrations, a pre-concentration step was introduced in the above system (Method B). This manifold has a lower detection limits (0.032 µg/mL) and high sensitivity (4 times greater than Method A). Both methods showed a good reproducibility (relative standard deviation for Method A = 1.9% and for Method B = 2.3%).
Vanadium(V) Spectrophotometry Stopped-flow Kinetic Method comparison

"Continuous-flow-through Solid Phase Spectrophotometric Determination Of Trace Amounts Of Zinc"
Anal. Chim. Acta 1998 Volume 375, Issue 1-2 Pages 71-80
M. J. Ayora-Ca&ntilde;ada, M. I. Pascual-Reguera and A. Molina-D&iacute;az*

Abstract: A flow-through solid phase spectrophotometric sensing device for the determination of Zn(II) was developed based on the reaction of this ion with 1-(2-pyridylazo)-2-naphthol (PAN) immobilized on a Dowex cation exchanger placed in a flow-through cell. The reaction of Zn(II) with immobilized PAN and its retention on the resin developed the analytical signal. Adequate dissociation of the Zn-PAN complex left the unaltered reagent fixed on the solid support, enabling the regeneration of the sensor. The sensor allows working with several calibration Lines simply by varying the sample volume injected for the determination. As an example, linear dynamic ranges from 0.2 to 4.0 µg mL-1 and from 20 to 500 µg L-1 can be obtained by using 100 and 2000 µl, respectively, with detection limits being 0.05 µg mL-1 and 5 µg L-1, respectively. The RSD (%) being 2.1 (100 µl) and 2.3 (2000 µl) and the sampling frequency 38 and 15 samples per hour, respectively. The sensor was applied to the determination of Zn(II) in real samples, namely, human hair, pharmaceutical and cosmetic preparations and water samples.
Zinc Spectrophotometry Optosensing Solid phase detection Linear dynamic range

"Determination Of Glycerol In Water By Flow Injection Analysis - A Novel Way Of Measuring Viscosity"
Talanta 1976 Volume 23, Issue 5 Pages 409-410
D. BetteridgeJ. Rika

Abstract: Flow injection analysis of mixtures of glycerol and water suggested that precise results may be obtained for the composition of miscible liquid mixtures over a narrow range. Since the viscosity is an important factor in the extent of mixing it could be determined simply and rapidly by this technique.
Glycerol Spectrophotometry Viscosity

"Metal Speciation By Flow Injection Analysis"
Talanta 1983 Volume 30, Issue 11 Pages 841-844
B. P. Bubnis, M. R. Straka and G. E. Pacey

Abstract: A two-channel flow-through switching valve incorporated in the manifold of the system permits determination of two oxidation states of an element. Addition of an appropriate oxidant or reductant is so timed as to allow complete conversion into a single oxidation state, so that measurement before and after the addition gives the concentration. of one and the sum of both species; thus, Fe(II) and Fe(III) are determined with 1,10-phenanthroline and Cr(III) and Cr(VI) with diphenylcarbazide, the absorbances being measured at 512 and 540 nm, respectively. When a 30 µL injection loop is used, rectilinear response is obtained for 0.5 to 30 ppm of Fe and 0.5 to 40 ppm of Cr. The coefficient of variation for each metal is ~1%. At 10 ppm of Fe, there is interference from 15 ppm of Ni, 50 ppm of Zn and 70 ppm of Cu. By increasing the injection-loop volume to 100 µL, it should be possible to lower the detection limit to 0.05 ppm of Fe. The error for total Cr is <2.0%, but is higher for Cr(III) and Cr(VI) individually. The method allows 180 injections to be made in 1 h.
Iron(2+) Iron(III) Chromium(III) Chromium(VI) Spectrophotometry Interferences Speciation

"Spectrophotometric Determination Of Micro Amounts Of Nitrite In Water And Soil"
Talanta 1983 Volume 30, Issue 5 Pages 374-376
Qian-Feng Wu and Peng-Fei Liu

Abstract: A spectrophotometric method for determination of µamounts of nitrite in water and soil with p-aminoacetophenone and resorcinol is described. The interference of foreign ions can be eliminated by masking with complexing agents. Beer's law is obeyed up to 20 g of NO2? in 60 mL of solution and the molar absorptivity at 435 nm is 5.27 x 104 l.mole? The color is stable for 10 hr. Results obtained by using the proposed method for water and soil samples agree well with those obtained by the Saltzman standard method.
Nitrite Spectrophotometry

"A Timed Solenoid Injector For Flow Analysis"
Talanta 1985 Volume 32, Issue 5 Pages 431-433
S. D. Rothwell and A. A. Woolf

Abstract: A timed solenoid valve is described, which can be easily constructed from readily available components, and which can be adapted for more complicated flow regimes. Samples can be reproducibility injected into flowing streams by timed switching of a sample stream with a miniature solenoid valve and timer circuit. The device is simpler to assemble and use than the standard rotary valve for which it was shown, by direct comparison of calibration data for the determination of P, to be an adequate alternative.
Phosphate Spectrophotometry Apparatus Valve

"Flow Injection Analysis With Multidetection As A Useful Technique For Metal Speciation"
Talanta 1986 Volume 33, Issue 3 Pages 199-202
J. Ruz, A. Rios, M. D. Luque de Castro and M. Valcarcel

Abstract: A flow injection system is described in which the simultaneous and separate determination of Cr(VI) and Cr(III) is effected with use of a single-beam spectrophotometer. The method involves injection of the reagent (1,5-diphenylcarbazide in aqueous ethanol plus Ce(IV) in dilute HNO3) into the sample solution, which acts as the carrier, and the reaction product is monitored at 540 nm. The max. ranges of the calibration graphs are from ~0.1 to 1.2 µg mL-1 for Cr(VI) and 0.5 to 6.0 µg mL-1 for Cr(III). The sequence of flow injection operations is explained, and details of normal, amplification and dilution procedures are presented.
Chromium(III) Chromium(VI) Spectrophotometry Dilution Rate constants Simultaneous analysis Speciation Tecator

"Sandwich Standardization In Flow Injection Analysis"
Talanta 1989 Volume 36, Issue 5 Pages 612-614
Angel Rios, M. D. Luque de Castro and Miguel Valcarcel

Abstract: The basic flow injection analysis configuration for sandwich standardization is illustrated. Sample and calibration solution fill the loops of two valves in an injection unit (illustrated), and, by continuous injection of the contents of both loops, sample and standards are introduced in a standard - sample - standard sequence. The resulting sandwich of plugs then merges with the reagent, thus creating three reaction zones each providing a signal on passage through the detector. The application of the method is demonstrated with the determination of formaldehyde in water by using the SO32- - pararosaniline system with spectrophotometric monitoring at 578 nm. Advantages of derivative over normal recordings are discussed. The basic flow injection analysis configuration for sandwich standardization is illustrated. Sample and calibration solution fill the loops of two valves in an injection unit (illustrated), and, by continuous injection of the contents of both loops, sample and standards are introduced in a standard - sample - standard sequence. The resulting sandwich of plugs then merges with the reagent, thus creating three reaction zones each providing a signal on passage through the detector. The application of the method is demonstrated with the determination of formaldehyde in water by using the SO32- - pararosaniline system with spectrophotometric monitoring at 578 nm. Advantages of derivative over normal recordings are discussed.
Formaldehyde Calibration Sample splitting Valve Injection technique Plug flow Detector

"Potassium Sodium Chloride Integrated Micro-conduits In A Potentiometric Analytical System"
Talanta 1991 Volume 38, Issue 9 Pages 989-993
Cui Hongbo and Sun Junyan

Abstract: An integrated micro-conduit flow injection analysis manifold has been developed that incorporates flow-through K+-, Na+- and Cl--selective electrodes. The characteristics of the electrodes were evaluated, showing a rapid response of 10 s, a reproducibility of ±0.1 mV, and stability over 8 h. Samples of water, soil extracts and serum were analyzed, giving results in agreement with those obtained by flame-photometric and AgNO3 titrimetric methods.
Chlorine Potassium Sodium Electrode Potentiometry Sample preparation

"Ion Mobility Spectrometry As Flow Injection Detector And Continuous-flow Monitor For Aniline In Hexane And Water"
Talanta 1992 Volume 39, Issue 5 Pages 459-467
Gary A. Eiceman*, Lizbeth Garcia-Gonzalez, Yuan-Feng Wang and Bobby PittmanG. Edward Burroughs,

Abstract: Ion mobility spectrometry (IMS) was used as a flow injection detector to quant. examine the ionization chemical of aniline in hexane. A 5 µL sample was vaporized at 15-90-s intervals in a flowing air stream and analyzed with an IMS equipped with acetone reactant ion chemistry, ambient temperature drift tube and membrane-based inlet. Precision was 3-11% relative standard deviation for 1-100 ppm aniline in hexane with 90-s injection intervals and detection limits were ~0.5 ppm with 5 µL injections. Matrix effects with amine and organic solvent mixtures were observed and corrected for low and medium proton affinity interferences with standard addition methods. Pronounced fouling of the IMS occurred when a continuous water flow was introduced for aqueous flow injection IMS. Continuous water monitoring without degraded IMS performance was possible by sampling air flow-through a Silastic tube immersed in an aqueous sample.
Aniline Spectrometry Interface Membrane Interferences

"Fluorimetric Determination Of Nitrite"
Talanta 1993 Volume 40, Issue 7 Pages 1009-1011
Nianqin Jie, Jinghe Yang and Fanqin Meng,

Abstract: A sensitive and rapid fluorimetric method for the determination of nitrite is described. The method is based on the reaction of nitrite with tryptophan to form a highly fluorescent compound in alkaline medium. The method has been applied in the determination of nitrite in water and food samples. [References: 16]
Nitrite Fluorescence

"Performance Of An Ion Trap Mass Spectrometer Modified To Accept A Direct Insertion Membrane Probe In Analysis Of Low Level Pollutants In Water"
Talanta 1993 Volume 40, Issue 7 Pages 1031-1039
Scott J. Bauer and R. Graham Cooks

Abstract: Modifications to a Finnigan ITS40 ion trap mass spectrometer are described which allow its use with a direct insertion probe. Details are given of the fabrication of a membrane probe for such an instrument. The membrane probe, which includes facilities for heating the fluid, employs a tubular membrane which is located just outside the electrode structure of the ion trap. Direct analysis of organic compounds in aqueous solution is demonstrated using a silicone membrane, with compounds such as benzene, chlorobenzene and dichloroethene being studied below the 1 ppb level. The effects of operating parameters including probe temperature, ion trap temperature, solution flow rate, mass spectrometer scan speed, and instrument tune procedures are explored in detail. Optimum performance characteristics are identified and trace level detection of eight organic compounds in the parts per trillion range is demonstrated. In seven of the eight cases studied, detection limits are below the EPA practical limit of quantitation levels. It is shown that the most sensitive mode of operation is when steady state passage of the analyte across the membrane is achieved, however, the time required for this is long in the case of some samples, and a dynamic flow injection analysis procedure is then favored. Use of the modified inlet system for solid sample introduction via a standard solids probe is also demonstrated. [References: 19]
Benzene Chlorobenzene Dichloroethene Mass spectrometry Membrane Interface PPT Silicone membrane Steady state

"Comparison Of The Simplex And Powell Methods With A Weighted Response Function For The Optimization Of FIA Systems"
Talanta 1993 Volume 40, Issue 7 Pages 1113-1126
L. M. B. C. &Aacute;lvares-Ribeiro and A. A. S. C. Machado*J. Alonso, J. Bartroli and M. del Valle,

Abstract: The cited optimization methods were compared with regard to the determination of nitrite in water by flow injection spectrophotometry based on the method of Nakashima et al, (Anal. Chim. Acta, 1974, 155, 263). Both methods proved to be effective for the optimization, neither having any definite advantages over the other. The use of a weighted response function in the optimization methods was useful in assessing the versatility of flow injection systems.
Nitrite Optimization Powell Simplex

"Speciation Of Dissolved Phosphorus In Environmental Samples By Gel Filtration And Flow Injection Analysis"
Talanta 1993 Volume 40, Issue 12 Pages 1981-1993
I. D. McKelvie* and B. T. HartT. J. Cardwell and R. W. Cattrall,

Abstract: Water (0.6 ml) was chromatographed on columns (10 cm x 1 cm i.d.) of Fast Desalting Sephadex G25, with a mobile phase (1.2 ml/min) of Tris hydrochloride of pH 4.65 (I = 0.005M). Sediments were extracted with 25 mM borate buffer of pH 9.2, the extracts were filtered and diluted (1:9). Portions (0.35 ml) of these solution were chromatographed on columns (4.2 cm x 1 cm i.d.) of Sephadex G25 Superfine, with the same mobile phase (0.65 ml/min). These columns partially separated high-mol.-wt. P compounds (exemplified by phytic acid, I) from low-mol.-wt. P compounds (exemplified by phosphate, II). The column effluent was mixed with 148 mM potassium persulfate solution in 25 mM borax (1.2 ml/min) and P compounds were oxidized by exposure to UV radiation. Subsequent reagents, 8.1 mM ammonium molybdate in 0.63 M H2SO4 (1 ml/min) and 0.89 mM SnCl2 and 15 mM hydrazine sulfate in 0.5 M H2SO4 (0.7 ml/min) were mixed in separately and absorbances were measured at 690 nm. Calibration graphs were linear for 100-1000 and 10^-100 µg/l of P with detection limits for I and II for the lower range were 27 and 1.1 µg/l as P.
Phosphorus Spectrophotometry Sample preparation Speciation Filtration Extraction

"Flow Injection Analysis Of Sulfite By Gas-phase Molecular Absorption UV-VIS Spectrophotometry"
Talanta 1997 Volume 44, Issue 6 Pages 1009-1016
A. Safavi* and B. Haghighi

Abstract: Sample solution (200 µL) was injected into a carrier stream of water (1.9 ml/min) which merged with a stream (1.9 ml/min) of 1 M H2SO4 and passed through a mixing coil (50 cm x 0.5 mm i.d.). N2 (17 ml/min) was introduced into the merged stream and the evolved SO2 diffused into the N2 gas segments in a second mixing coil (30 cm). The SO2 was separated in a gas-liquid separator (diagram given) and passed to a flow cell (diagram given) where the absorbance was measured at 200 nm. The detection limit was 0.8 µg sulfite and calibration graphs were linear for up to 120, 120-240 and 240-440 µg. The RSD were 1.02% and 0.76%, respectively, for 70 and 220 µg sulfite. Sample throughput was 40/h. Little interference was observed. The method was applied to water and lemon juice. Recoveries were >=95.2%.
Sulfite Spectrophotometry Gas phase detection Gas diffusion Interferences Phase separator

"A Photo-cured Coated-wire Calcium Ion-selective Electrode For Use In Flow Injection Potentiometry"
Talanta 1997 Volume 44, Issue 8 Pages 1397-1405
Peter W. Alexandera,*, Telis Dimitrakopoulosa and D. Brynn Hibbertb

Abstract: A polymer mixture containing 49.2% bisphenol A epoxy diacrylate, 24.6% 1,6-hexanediol diacrylate, 0.8% 9,10-phenanthrenequinone, 0.8% diphenyliodonium chloride, 21.7% 2-nitrophenyl octyl ether, 1.4% NNN'N'-tetracyclohexyl-3-oxapentane diamide and 1.5% tetradodecylammoniumtetrakis-(4- chlorophenyl)borate was applied onto four Ag electrodes (0.8 mm i.d.) incorporated in a flow-through cell, then exposed to UV irradiation at 300 nm (250 W) for 1 min. The resulting ISE was conditioned in 100 mM CaCl2 and used to determine Ca by flow injection potentiometry under steady-state conditions. The carrier was 10 mM NaHCO3 buffer of pH 8.3. The calibration graphs were linear for 0.5-10 mM Ca2+ and the detection limit was 0.01 mM. The 90% response time was 5 s and RSD (n = 3) were 1-4%. Results for the analysis of water samples agreed with those obtained by AAS., , A multi-sensor cell containing a new photo-cured calcium ion selective electrode sensor is reported. Four membranes containing different components are prepared to determine the one with optimum selectivity and sensitivity. This is shown to consist of the N,N,N',N'-tetracyclohexyl-3-oxapentanediamide ligand (ETH 129) as the ionophore, 2-nitrophenyl octyl ether as the plasticiser and tetradodecyl ammonium tetrakis(4-chlorophenyl) berate as the lipophilic additive. The photo-curing process is applied after coating a thin membrane on a silver wire as substrate transducer to produce the calcium sensor. The curing process is demonstrated to be faster (1 min) than previous methods and does not require a nitrogen atmosphere for reproducible production of membrane response characteristics. Four sensors constructed with the identical optimum membrane are shown to function reproducibly in a multi-sensor flow-through cell using the steady-state mode of flow measurement, and an average calibration slope of 28.5±0.4 mV change per activity decade is observed over a log-linear concentration range between 0.01 and 10 mM. The sensor is also shown to respond to changes in pH. Hence, in the flow injection potentiometric mode, a constant carrier buffer composition of pH 8.3 is required for accurate potentiometric calcium determinations. The sensor is used to determine calcium in water samples by flow injection potentiometry. The accuracy of the electrode determination relative to atomic absorption spectroscopy was in the range 5-9% for three different water samples. (C) 1997 Elsevier Science B.V.28 References
Calcium Electrode Electrode Potentiometry Electrode Method comparison

"Flow Injection Determination Of Hydrazine With Fluorimetric Detection"
Talanta 1998 Volume 47, Issue 3 Pages 645-649
Ali A. Ensafi* and B. Rezaei

Abstract: A spectrophotometric flow injection system for the determination of hydrazine, involves oxidation of hydrazine by Th(III) with concomitant formation of Th(I). The optimum anal. conditions were established. The linear range for hydrazine is 25-500 ng/mL with a detection limit of 20 ng/mL. The sampling frequency is 40±5 samples/h. The relative standard deviation for 100, 250 and 500 ng/mL is 3.5, 2.6 and 1.8%, respectively. The method was applied to the determination of hydrazine in water.
Hydrazine Fluorescence Optimization Indirect

"Rapid Determination Of Chromium(VI) By Flow Injection Analysis"
Analyst 1980 Volume 105, Issue 1248 Pages 292-295
S. Storgaard J&oslash;rgensen and Marisa A. B. Regitano

Abstract: The photometric determination of chromium(VI) in natural waters and soil extracts as the 1,5-diphenylcarbazide complex is well established as a standard method.(1) The complex is formed rapidly, has a high absorptivity at 540 nm and the method is highly selective when the pH is kept at 1-2. For rapid analysis of small sample volumes this method appears to be ideally suited for adaptation to the continuous flow injection technique of Ruzicka and co-workers.(2-4) The present investigation was undertaken when chromium(VI) had to be determined in a considerable number of soil extracts during a study of the behavior of chromium in soils.(5)
Chromium(VI) Spectrophotometry Extraction

"Kinetic Determination Of Nitrite In Waters By Using A Stopped-flow Analyzer"
Analyst 1982 Volume 107, Issue 1280 Pages 1309-1315
M. A. Koupparis, K. M. Walczak and H. V. Malmstadt

Abstract: Automatic kinetic methods for the determination of nitrite in waters with a stopped-flow analyzer. are described. The methods are based on the diazotisation of sulphanilamide, the product being coupled with N-(1-naphthyl)-ethylenediamine dihydrochloride to form a highly colored azo dye, which is measured at 540 nm. A single-point kinetic procedure uses a delay time of 10 s and one measurement of 0.7 s. A multi-point reaction rate method uses a delay time of 0.8 s and a measurement time of 1.5 s. The methods are fast, sensitive, accurate and precise, and without serious interference. The sample throughput for routine analysis can be up to 360 samples per hour in the range 0.025-2.00 p.p.m. of nitrite-nitrogen.
Nitrite Spectrophotometry Kinetic Stopped-flow

"Potentiometric Determination Of Sulfite By Use Of Mercury(I) Chloride-mercury(II) Sulfide Electrodes In Flow Injection Analysis And In Air-gap Electrodes"
Analyst 1983 Volume 108, Issue 1287 Pages 701-711
Geoffrey B. Marshall and Derek Midgley

Abstract: Flow injection analysis, using as the detector a solid-state ion-selective electrode with a mercury(II) sulphide-mercury(I) chloride membrane, can be used for determining sulphite or dissolved sulphur dioxide in water. At concentrations in the range 1.5-10 mg 1-1 of sulphite, the method has a Nernstian response of 60 mV per decade, but at lower concentrations (down to 0.1 mg 1-1) the e.m.f. is linearly related to the sulphite concentration. Although the flow injection method is less sensitive than direct use of the electrode, it avoids the problem of chloride interference and permits the determination of sulphur dioxide in the commonly used tetrachloromercurate absorbent. The only serious interference found was from sulphide, although a small effect was also obtained from thiosulphate. Measurements in the range 0.1-10 mg 1-1 of sulphite had relative standard deviations for single results of no more than 2%. The method requires only two reagents (dilute nitric acid solutions) and is simple to operate. Each analysis is complete in less than 5 min.Air-gap electrodes, using the same sensor, had sub-Nernstian responses of very poor reproducibility and were not considered to be a practical means of determining sulphite.
Sulfite Potentiometry Conductometry Electrode Electrode Electrode Electrode

"Enzymatic Determination Of Urea In Water And Serum By Optosensing Flow Injection Analysis"
Analyst 1986 Volume 111, Issue 8 Pages 865-873
Tracy D. Yerian, Gary D. Christian and Jaromir Ruzicka

Abstract: During flow injection analysis, the pH change associated with the enzymatic degradation of urea to NH3 and HCO3- is measured by reflectance spectrophotometry via a fiber-optic sensor. The pH change is detected by monitoring the reflectance spectrum of a ColorpHast (Merck) indicator strip that is situated in an integrated micro-conduit at the tip of a bifurcated fiber-optic bundle. Samples (50 µL) and reagent (25 µL of a solution containing 60 mg of urease per 100 mL of carrier buffer) are injected into the carrier buffer, containing 1 mM Tris - HCl and 140 mM NaCl (pH 7.0 for aqueous solution or 7.4 for serum samples), via a split-loop injector, and the intensity of the reflected light is monitored at 610 nm. To minimize errors due to variations in the background sample pH, a stopped-flow kinetic procedure is used. For human serum, the response is rectilinear up to 2 mM urea. Results for 12 samples of human serum agreed with those obtained by an ASTRA enzymatic method with conductometric detection.
Urea Spectrophotometry Enzyme Kinetic Method comparison Optical fiber Optosensing Stopped-flow

"Determination Of The Stoichiometry For Complexes By Flow Procedures. Molar Ratio And Asmus Methods"
Analyst 1986 Volume 111, Issue 11 Pages 1317-1320
J. Martinez Calatayud, P. Camp&iacute;ns Falc&oacute; and M. C. Pascual Mart&iacute;

Abstract: Molar-ratio and Asmus methods for the determination of the stoichiometry of complexes were adapted to flow techniques. The procedures were tested for La(III)-Arsenazo I, Fe(II)-1,10-phenanthroline, Th(IV)-Thorin, Th(IV)-Alizarin S and Ce(III)-Arsenazo III. The method proposed is based on the merging of two solutions (metal and reagent), keeping the flow-rate of one of them constant and increasing the other stepwise. The graphs obtained and their theoretical basis are discussed.
Cerium(3+) Iron(2+) Lanthanum(3+) Thorium(IV) Spectrophotometry Complexation Gradient technique Stoichiometry

"Open Thin Layer Cell - A Flow-through Electrode For Potentiometric Stripping Analysis"
Analyst 1987 Volume 112, Issue 2 Pages 133-136
Wolfgang Frenzel and Gerhard Schulze

Abstract: An electrochemical flow-through cell is described that is substantially different from all conventional cells. It has an open structure and is made from a piece of Plexiglass that contains the working and auxiliary electrodes. The flow channel is replaced by a strip of filter paper, which adheres to the cell body and covers the inlet hole and both electrodes. The carrier solution is therefore precisely directed along the filter strip, which dips into the waste reservoir containing the SCE.Potentiometric stripping analysis (PSA) was used to evaluate the performance characteristics of the cell in terms of flow-rate, injection volume and carrier composition. Linear calibration graphs were obtained in two concentration ranges (10-500 µg l-1 and 1-10 mg l-1) for Cd, Pb and Cu under slightly different experimental conditions. The practical advantages and the long-time response stability of the cell were demonstrated by the PSA determination of Zn in tap water. In the range 0.1-20 mg l-1 a sample throughput of 120 h-1 is obtainable with a reproducibility better than 5%.
Cadmium Copper Lead Zinc Electrode Potentiometric stripping analysis Tecator

"Flow Method For The Titration Of Weak Acids Or Weak Bases Using Linear Titration Plots"
Analyst 1987 Volume 112, Issue 7 Pages 1063-1066
Martinez Calatayud, P. Campins Falc&oacute; and R. Mic&oacute; Albert

Abstract: Continuous flow titrations of weak acids or weak bases can be carried out with a simple apparatus if the pH and titrant flow-rate data are treated using a linear titration plot method. Titrant is added to a flowing sample stream by a peristaltic pump with a precisely adjustable rotation rate. The results obtained for a variety of weak acids and weak bases are similar in accuracy to those given by corresponding burette titrations of discrete portions of sample.
Acids, weak Bases, weak Potentiometry Titrations

"Microdetermination Of Fluoride In Water By Ion-exchange Spectrophotometry"
Analyst 1988 Volume 113, Issue 3 Pages 419-422
L. F. Capit&aacute;n-Vallvey, M. C. Valencia and J. M. Bosque Sendra

Abstract: A method for the determination of microgram per litre levels of fluoride has been developed, based on ion-exchange spectrophotometry (IES). The fluoride reacts with slightly polymerised zirconium and xylenol orange and the reaction product is sorbed on Dowex 1-X8 resin. The absorbance of the resin phase at 580 and 750 nm is measured directly. The calibration graph is linear in the concentration range 2-20 µg l-1 and the RSD is 1.8%. The determination limit with 500 mL of sample is 1.1 µg l-1; the sensitivity can be enhanced by increasing the sample volume. The method has been applied to the determination of fluoride in tap and raw water using 500 mL of sample.
Fluoride Ion exchange Spectrophotometry Preconcentration

"Automated Spectrophotometric Determination Of Titanium(IV) In Water And Brines By Flow Injection Based On Its Reaction With Hydrogen Peroxide"
Analyst 1990 Volume 115, Issue 3 Pages 315-318
M. Mu&ntilde;oz, J. Alonso, J. Bartrol&iacute; and M. Valiente

Abstract: A flow injection system is described (with diagram). Water (13 µL) in H2SO4 was injected into a 0.7 M H2SO4 carrier stream (2.2 mL min-1) and diluted in a coil (50 cm x 0.7 mm) with water (2.2 mL min-1). The stream was then mixed in a coil (1 m x 0.7 mm) with 3% (w/v) H2O2 in 0.7 M H2SO4 (2.2 mL min-1) and the absorbance was measured at 410 nm. Calibration graphs of Ti in the sample were rectilinear up to 1000 ppm at a sampling rate of 240 hmin1. Detection limit was 9 ppm, and the coefficient of variation was 0.6%. Interference from Fe, V and Mo can be avoided by selective precipitation during sample pre-treatment. A system is also described for the determination of low Ti concentration. in brine using 3.3 M Mg(NO3)2 - 1 M HCl as carrier; the calibration graph was rectilinear up to 30 ppm, coefficient of variation were 0.7% and the detection limit was 0.3 ppm.
Titanium(IV) Spectrophotometry Automation Dilution Calibration Detection limit Interferences

"Flow Injection Chemiluminescence Method For The Selective Determination Of Chromium(III)"
Analyst 1993 Volume 118, Issue 6 Pages 643-647
Rosario Escobar, Qingxiong Lin, Alfonso Guira&uacute;m and Francisco F. de la Rosa

Abstract: The cited determination was based on the measurement of light emitted from the Cr(III)-catalyzed oxidation of luminol by H2O2. The flow cell of the flow injection system was a coiled PTFE tube (1 mm i.d.). Luminol and H2O2 were dissolved in 0.2 M CO32- - HCO3- buffer. Luminol and H2O2 were mixed in the flow system and then with the flow of water in which the sample was injected. The chemiluminescence was recorded as a function of time over 5 s. The max. emission intensity was proportional to the Cr(III) concentration. in the sample. The addition of 0.1 mM EDTA reduced interference from other metal cations. The calibration graph was rectilinear from 0.01 (detection limit) to 6 ppb of Cr(III). The cited method was applied in the determination of Cr(III) in water and food. Recoveries ranged from 96 to 110% and 92 to 108.5% in food and water samples, respectively. The coefficient of variation (n = 15) was 2.5%.; the method can analyze up to 70 samples h-1.
Chromium(III) Chemiluminescence Interferences

"Sequential Determination Of Calcium And Nitrate Ions In Waters By Potentiometric Flow Injection"
Analyst 1993 Volume 118, Issue 12 Pages 1527-1532
Julian Alonso-Chamarro, Jordi Bartrol&iacute;, Siao Jun, Jose Luis F. C. Lima and M. Concei&ccedil;ao B. S. M. Montenegro

Abstract: Water (100 µL) was injected into a carrier stream (3.5 ml/min) of 0.02 M sodium acetate containing 4 µM-calcium nitrate and the solution passed through a mixing coil (no dimensions given) before detection with a calcium tubular potentiometric electrode (described). The solution was then mixed with an auxiliary carrier solution (3.5 ml/min) of 0.02 M lead acetate/0.01 M lead oxide before detection with a nitrate tubular potentiometric electrode (described). Diagrams of the flow injection manifold and the tubular electrode design are given. The response slope and lower limit of linear response were 53.4 mV/decade and 10^-4.3M, respectively, for the nitrate sensor, and 31.3 mV/decade and 10^-4.75M, respectively, for the calcium sensor. The RSD (n > 4) was 1% and the sample throughput was 145/h. Recoveries were quantitative. Results agreed with those obtained by AAS and spectrophotometry. The method permits the simultaneous determination of calcium and nitrate in most water samples (excluding those with a high saline content).
Calcium Nitrate Potentiometry Dual detection

"Online Determination Of Chromium By Adsorptive Cathodic Stripping Voltammetry"
Analyst 1994 Volume 119, Issue 2 Pages 293-297
Andrew M. Dobney and Gillian M. Greenway

Abstract: An online system for the cited analysis is described (diagram of flow manifold given). The system was operated in two steps. In the first step, 11.7 mM mercury nitrate in 0.5 M HNO3 was injected into the carrier stream of 0.5 M acetate buffer solution of pH 6.1 (0.2 ml/min) which was then transported to the vitreous carbon electrode in a flow cell where a mercury film was formed by scanning from -0.97 to +0.1 V for 600 s at 10 mV/s. In the second step, sample solution was injected into the carrier stream which was merged with a stream (0.2 ml/min) of 10 mM diethylenetriaminepenta-acetic acid and 0.3 M NaNO3 in the above buffer solution The resulting stream was carried to the flow cell containing the mercury film electrode, where Cr was determined vs. Ag/AgCl by scanning from -1.07 to -1.4 V at 10 mV/s with a deposition time of 60 s. The calibration graph was linear up to 10 ppb Cr(VI); in the determination of 2 ng/ml Cr(VI), the RSD was 2-3% and the detection limit was 0.2 ng/ml. Results are discussed.
Chromium(VI) Voltammetry Electrode

"Anodic-stripping Voltammetry With A Triton X-100 Modified Mercury-film Electrode Using Flow Injection"
Analyst 1994 Volume 119, Issue 7 Pages 1603-1606
Ruelito R. Dalangin and Hari Gunasingham

Abstract: Experiments were performed with a PAR Model 174A polarographic analyzer. using solutions containing 0.5 µg/ml Pb and a mixture of 0.5 µg/ml in Cd(II), Pb(II) and Cu(II). The working electrode was a vitreous C disc embedded in PTFE, the reference electrode was Ag/AgCl and the counter electrode graphite. Scan rate was 20 mV/s. At concentrations below the critical micellization concentration (cmc), the effect of Triton X-100 is a fall in the stripping peak current and a corresponding decline in sensitivity. This results from adsorption of the surfactant on to the Hg film electrode. Above the cmc however, deactivation of the electrode is reversed, resulting in better sensitivity and lower background currents.
Lead(2+) Cadmium(2+) Copper(II) Voltammetry Electrode Triton X Sensitivity Surfactant

"Investigation Into The Detection Of Chlorine Species By Rhodamine 6G Chemiluminescence With Electrochemical Modification"
Analyst 1995 Volume 120, Issue 2 Pages 477-483
Gordon P. Irons and Gillian M. Greenway

Abstract: A flow system for free chlorine determination was developed. A portion (140 µL) of the sample (hypochlorous acid; I) in 0.1 M phosphate buffer of pH 6.7 was injected into a an aqueous carrier stream (2 ml/min) which merged with a stream (2 ml/min) of 2 mM Rhodamine 6G in 5% Tween 40. The chemiluminescence produced was measured. The detection limit was 90 µg/l of free chlorine and the calibration graph for up to 4 ppm I is shown. No RSD are given. The flow system was used to investigate whether other chlorine species, not normally detected by Rhodamine 6G chemiluminescence, could be detected by electrochemically-modified chemiluminescence in the presence of a charged Pt electrode. The analytes tested were NaCl, NH4Cl, KClO3, NaClO4, sodium hypochlorite and a mixture of chloramines. All the analytes tested except hypochlorite exhibited voltage-dependent chemiluminescence. The possibility of using Rhodamine 6G chemiluminescence combined with electrochemical modification to quantify a number of chlorine-containing species in water is discussed.
Chlorine, free Chemiluminescence Optimization

"Use Of Focused Microwaves For Expeditive Shortening Of Sample Pre-treatment: Digestion And Reduction Procedures Prior To Selenium Speciation As Selenium(IV) Or Selenium(VI)"
Analyst 1995 Volume 120, Issue 8 Pages 2171-2174
W. Bryce, A. Izquierdo and M. D. Luque de Castro

Abstract: Methods for sample digestion and reduction of Se(VI) to Se(IV) using a focused microwave digestor, prior to Se determination, are described. The sample digestion method consisted of a three-step microwave digestion programme, using HNO3 and H2O2 (details given). The reduction of Se(VI) to Se(IV) was carried out online in a flow injection manifold in a 1 m Teflon reactor placed in the microwave chamber, using 6 M HCl as reductant. After reduction, the sample stream was diluted online before Se(IV) determination by flow injection cathodic stripping voltammetry (details given). The methods were applied to various sample types, viz., milk, sausage, kidney and water, and reduced the time required for both sample digestion and Se(VI) reduction.
Selenium(VI) Selenium(IV) Sample preparation Voltammetry Heated reaction Microwave Speciation

"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 Ion exchange Spectrophotometry Resin Glass beads Column Matrix removal Preconcentration

"Online Preconcentration Of Nickel By Carbonyl Vaporization With Flow Injection And Continuous-flow Systems In Combination With Sensitive Determination By Electrothermal Atomic Absorption Spectrometry"
Analyst 1995 Volume 120, Issue 11 Pages 2699-2705
Dietmar Erber and Karl Cammann

Abstract: A carrier stream of 0.08 M H2SO4 containing the sample was merged with a stream of 1% NaBH4. The solution was then merged with a stream of CO and the mixture was passed through a 20 cm reaction coil. The Ni(CO)4 produced was carried by an Ar stream to a gas/liquid separator and then to a graphite furnace pre-heated to 250°C, where the Ni(CO)4 was decomposed and the Ni produced was trapped on the graphite surface. The trapped Ni was subsequently determined by ETAAS at 232 nm, using an atomization temperature of 2400°C. Both flow injection (FI) and continuous-flow (CF) modes were used for sample introduction, with sample volumes of 0.1-1 and 1-50 ml, respectively. A diagram of the system used is given. Detection limits were 0.18 and 0.01 µg/l of Ni for FI and CF modes, respectively. The RSD (n value not given) was 3%. The method was applied to two certified reference materials, viz., water and rye grass (Lolium). The results obtained agreed with the certified values for Ni.
Nickel Spectrophotometry Method comparison Reference material Volatile generation Preconcentration Volatile generation

"New Approach To Sequential Injection Analysis: Using The Sample As Carrier"
Analyst 1998 Volume 123, Issue 7 Pages 1541-1546
Francisca Mas, Andreu Cladera, Jos&eacute; Manuel Estela and V&iacute;ctor Cerd&agrave;

Abstract: A new way of implementing sequential injection analysis involving the use of the sample as a carrier is proposed. These systems are especially suitable for constructing continuous monitoring set-ups with no restrictions regarding the amount of sample which can be processed. A new standard addition methodology was used to calibrate the proposed system. The methodology was applied to the determination of Fe(II) with o-phenanthroline (a reaction which involves a single reagent) and that of P by formation of a blue heteropoly acid (a reaction involving two reagents). The anal. rate is 8 min per sample (3 standard additions). The manifold design together with an adequate program of aspiration-impulsion movements avoids the memory effects between samples. Determination of Fe(II) is linear between 0.25 and 6 mg L-1 Fe(II). In the analysis of a sample containing 2.3 mg L-1 Fe(II) (n = 10) a relative standard deviation of 1.7% was obtained. The detection limit (3s) is 0.06 mg L-1 Fe(II) and the determination limit (10s) 0.2 mg L-1 Fe(II). Determination of P is linear between 0.1 and 1 mg L-1 P and in the analysis of a sample containing 0.75 mg L-1 P (n = 10) a relative standard deviation of 4.1% was obtained. The detection limit is 0.02 mg L-1 P and the determination limit 0.1 mg L-1. Both methods were applied to the determination of Fe and P in spiked waters. The use of the methodology based on the standard addition was evaluated in the case of P determination to eliminate interferences of the multiplicative type.
Iron(2+) Phosphorus Spectrophotometry Sequential injection Standard additions calibration Interferences Reverse

"Spectrofluorometric Determination Of Paraquat By Manual And Flow Injection Methods"
Analyst 1998 Volume 123, Issue 7 Pages 1577-1581
Tom&aacute;s P&eacute;rez-Ru&iacute;z, Carmen Mart&iacute;nez-Lozano, Virginia Tom&aacute;s and Jos&eacute; Fenoll

Abstract: The reaction involving the formation of a fluorescent charge-transfer complex between paraquat and benzaldehyde was studied in ethanol-water medium. In the presence of a large excess of benzaldehyde, the fluorescence intensity is linearly related to paraquat concentration. from 0.13 to 7.4 µg mL-1. The method can be easily adapted to a flow system using a two-channel manifold, the peak height being proportional to the paraquat concentration. over the range 1.6-22.3 µg mL-1. Manual and flow injection procedures were satisfactorily applied to the determination of paraquat in commercial herbicides, waters, soils and potatoes.
Paraquat Fluorescence Complexation

"Indirect Determination Of Nitrate By Electrothermal Atomic Absorption Spectrometry Using An Online Cadmium Microcolumn"
Analyst 1998 Volume 123, Issue 7 Pages 1561-1564
E. Vereda Alonso, M. T. Siles Cordero, M. P. Caballero Torres, A. Garc&iacute;a de Torres and J. M. Cano Pav&oacute;n

Abstract: The proposed indirect automatic method is based on the reduction of nitrate to nitrite using a cadmium reductant microcolumn where the flow of the sample through the microcolumn oxidizes the metallic cadmium to Cd(II), which is measured by electrothermal atomic absorption spectrometry. The automatic system is achieved simply by replacing the sample tip of the autosampler arm with the reductant microcolumn. This system results in a powerful integrated system which permits fully automated operation, avoiding time-consuming manual work and enhancing the sensitivity. The manifold was evaluated with respect to accuracy, precision and sensitivity for nitrate determination in water, the detection limit achieved being 0.05 g mL-1 (3s) with a sampling rate of about 35 h-1. A 2.3% relative standard deviation was obtained in a repeatability study (n = 11) at the 0.2 g mL-1 level of nitrate and 2.6% at the 8.0 g mL-1 level. Some ions which commonly occur with nitrate in water samples, such as Na+, Ca2+ and Mg2+, interfered to a certain extent, although these interferences were minimized by passing of the sample through an Amberlite cation-exchange resin. The method was applied to samples of bottled and spring waters with good results. The matrix effects were minimized by using the standard addition method.
Nitrate Spectrophotometry Reduction column Extraction Indirect

"Non-aqueous Enzymic Flow Injection Determination Of Cholestanol In Sediments"
Analyst 1998 Volume 123, Issue 11 Pages 2291-2295
Gerardo Pi&ntilde;eiro-Avila, Amparo Salvador and Miguel de la Guardia

Abstract: A procedure was developed for the spectrophotometric determination of cholestanol in sediments based on its extraction with chloroform-methanol (2+1 v/v), dissolution of the extracts, after pre-concentration, in pH 7.0 buffer-saturated toluene containing 10^-3 M p-anisidine and enzymatic determination in non-aqueous media using a bienzymatic reactor consisting of 1 mg of cholesterol oxidase and 1 mg of horseradish peroxidase non-covalently co-immobilized on controlled pore glass beads. A limit of detection of 2.0 x 10^-6 M was obtained under the optimum experimental conditions and recoveries of 95-118% were obtained in the anal. of water and beach sediment samples spiked with cholestanol at concentrations 0.4-1.0 mg/g. This method can also be used for the determination of cholesterol in sediment extracts, the analytical sensitivity for cholestanol being half that for cholesterol, studies were carried out in order to determine accurately both compounds in the same sample.
Cholestanol Cholesterol Spectrophotometry Immobilized enzyme Controlled pore glass Optimization

"Automation In Element Preconcentration With Chelating Ion Exchangers"
J. Anal. At. Spectrom. 1987 Volume 2, Issue 6 Pages 611-614
G&uuml;nter Knapp, Kurt M&uuml;ller, Martin Strunz and Wolfhard Wegscheider

Abstract: A microprocessor controlled pre-concentration system that permits the automated off-line pre-concentration of several samples at the same time is described. Trace elements pre-concentrated from sample volumes of up to several hundred millilitres can be eluted by 5 mL of 2 M nitric acid. It is therefore possible to achieve pre-concentration factors of up to 100. In contrast to FIA methods all ICP-AE spectrometers can be used for the measurements. Four different chelating ion-exchange materials, Chelex 100, oxine cellulose, CPPI resin and Hyphan cellulose, were compared. Trace elements were enriched from concentrated salt solutions and from NBS standard reference materials following decomposition in the High Pressure Asher. After elution the elements were measured by ICP-AES (Plasma II) and by graphite furnace AAS (HGA-500/Zeeman 5000). Under the conditions tested, Chelex 100, the oxine cellulose and the CPPI resin can be employed satisfactorily in the automated pre-concentration of a number of elements.
Cadmium Copper Lead Manganese Nickel Zinc Ion exchange Spectrophotometry Spectrophotometry Chelation Computer Preconcentration

"Flow Injection Electrothermal Atomic Absorption Spectrometry For Arsenic Speciation Using The Fleitmann Reaction"
J. Anal. At. Spectrom. 1993 Volume 8, Issue 2 Pages 229-233
M. Burguera and J. L. Burguera

Abstract: Arsine was generated by the Fleitmann reaction (from aqueous As(III) - NaOH - KI) in a flow injection system and was carried forward by a low flow of Ar (40 mL min-1) into a graphite furnace coated with a suitable metal absorber. The best absorber was Pd at 200°C, but Ag, Ce, Pt and Ru could be used with decreased sensitivity. With use of a furnace program of 90°C for 15 s and 120°C for 10 s for absorber drying, 200°C for 50 s for arsine deposition and 2600°C for 3 s for As atomization, down to 10 pg of As could be detected. At 15 µg L-1 (or 15 ng) the coefficient of variation (n = 10) was 3.5%. The results obtained for total As in reference materials compared well with certified values. The method was also applied in the speciation of As in waters, results were satisfactory.
Arsenic(3+) Arsenic(5+) Spectrophotometry Speciation Reference material

"Comparative Analysis Of Aluminum Oxide Powders By Inductively Coupled Plasma-mass Spectrometry With Low And High Mass Resolution"
J. Anal. At. Spectrom. 1996 Volume 11, Issue 9 Pages 797-803
Norbert Jakubowski, Wolfgang Tittes, Dagmar Pollmann, Dietmar Stuewer and Jos&eacute; A. C. Broekaert

Abstract: ICP-MS with low and moderate mass resolution was applied to the determination of trace elements (B, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Zr, Ba, La and Ce) in two different pare Al2O3 powders after decomposition. Four different sets of measurements were performed: (1) with quadrupole instrument in standard operation; (2) with the same instrument including an online matrix trace separation step; (3) with a double-focusing magnetic field instrument operated at;low resolution (R=300); and (4) with the same instrument operated with moderate resolution (R=3000). Generally, the quantitative results obtained with the four different techniques are in good agreement. Application of the double-focusing instrument with moderate mass resolution permitted the determination of spectrally interfering elements such as V, Cr, Mn, Fe and Ga in Al2O3 in the 0.04-10 µg g-1 range far above the detection limit. For all four applied techniques, blank values arising from the reagents and instrumentation were a major limitation for a number of elements, and the lowest detection limits were obtained in each instance for elements that do not suffer from limitations due to blank values.
Trace elements Boron Titanium Vanadium Chromium Manganese Iron Cobalt Nickel Copper Zinc Gallium Zirconium Barium Lanthanum Cerium Mass spectrometry Interferences Method comparison

"Continuous Determination Of Ascorbic Acid By Photobleaching Of Methylene Blue"
Anal. Chem. 1972 Volume 44, Issue 7 Pages 1267-1269
Vance R. White and J. M. Fitzgerald

Abstract: An apparatus for the determination of ascorbic acid, via the photobleaching of the methylene blue carrier stream, was discussed and the appropriate diagram presented. The signal was measured by an Atomic Absorption (AA) spectrophotometer and a major advantage to the system is its ability to regenerate the methylene blue carrier stream via the oxidation of methylene blue by diatomic oxygen. Day to day reproducibility was very good and a discussion of interferences (mostly from aromatic components) is presented along with a table outlining the various interference levels. A discussion of the results for the analysis of orange juice, water, and vitamin C tablets are presented.
Ascorbic acid Spectrophotometry Apparatus Indirect Interferences Photochemistry

"Sample Flow Velocity And Low Level Sodium Ion Measurement With The Glass Electrode"
Anal. Chem. 1975 Volume 47, Issue 13 Pages 2307-2309
Edgar L. Eckfeldt and William E. Proctor Jr.

Abstract: The accuracy is increased and time and volume of solution required for anal. are decreased when an insert is placed in the sensor bulb portion of a sodium [7440-23-5] ion analyzer to increase the flow velocity of the sample solution passing the sensor bulb surface. By this procedure the flow rate is decreased from 150 to <10 ml/min and as little as 0.1 ppb Na can be determined in water [7732-18-5].
Sodium Electrode Theory

"Kinetically Assisted Equilibrium Based Repetitive Determination Of Iron(II) With Ferrozine In Flow-through Systems"
Anal. Chem. 1976 Volume 48, Issue 8 Pages 1207-1211
V. V. S. Eswara Dutt, A. Eskander-Hanna, and Horacio A. Mottola

Abstract: Repetitive determination based on injection of the sample containing the sought-for species into a continuously circulated reagent mixture are described. Injection occurs directly into the detector chamber and the determination Is based on two consecutive processes: 1) a fast chemical reaction taking place in the detection zone, and 2) the washing out of the generated signal as a result of the Imposed flow. Practical application of the approach is illustrated with the determination of iron( It) in aqueous solutions utilizing the organic reagent Ferrozine. This method was applied to the determination of Iron In EPA Quality Control Water Samples, lake water, and tap water.
Iron(2+) Spectrophotometry Complexation Kinetic Closed loop

"Non-membrane Amperometric Sensor For Dissolved Oxygen In Flow-through Systems"
Anal. Chem. 1977 Volume 49, Issue 13 Pages 2118-2121
C. Michel Wolff and Horacio A. Mottola

Abstract: This paper reports on the design and performance of an electrolytic (amperometric), nonmembrane, three-electrode system with fast response to changes in dissolved oxygen concentration and specially suitable for use with solutions flowing in narrow tubing at constant rate. The device is of utility in situations where a fast response is needed such as in sample injection techniques in continuous flow analysis.
Oxygen Amperometry Sensor Membraneless

"Determination Of Anionic Surfactants By Flow Injection Analysis Based On Ion-pair Extraction"
Anal. Chem. 1979 Volume 51, Issue 11 Pages 1640-1643
Jiro Kawase, Atsuo Nakae, and Makoto Yamanaka

Abstract: The ion-pair extraction of anionic surfactants by flow injection analysis at a rate of 80 samples/h is described. The extraction system water-MeOH-CHCl3 is used. The phase-sepg. material is a porous membrane of PTFE [9002-84-0] which is permeable to CHCl3 and impermeable to the aqueous solution The method is useful with surfactant concentrations ≤1.25 mM. Reproducibility of <1.5% coefficient of variance is obtained.
Surfactants, anionic Spectrophotometry Sample preparation Ion pair extraction Preconcentration Teflon membrane

"Automated Determination Of Cationic Surfactants By Flow Injection Analysis Based On Ion-pair Extraction"
Anal. Chem. 1980 Volume 52, Issue 13 Pages 2124-2127
Jiro Kawase

Abstract: An automated ion-pair extraction of cationic surfactants by flow injection analysis (FIA) is described. A more simplified and effective solvent extraction system has been constructed. Novel components include the pumping system, an effective segmentor for the immiscible phases, and a highly selective phase separator with a poiy(tetrafiuoroethy1ene) membrane. The effects of segmentor and separator, inner diameter and length of extraction coils, and methanol content in the aqueous reagent have been examined on the extractability and sample band broadening. The relative molar extractability of the surfactants was studled In terms of both the type and the alkyl group of each homologue. Equal molar response, and good reproducibility (within 1.5 % coefficient of variation automatically injected), and linear response were obtained with the six different types.
Surfactants, cationic Sample preparation Ion pair extraction

"Simultaneous Determination Of Total Nitrogen And Total Oxygen Demand In Aqueous Samples"
Anal. Chem. 1982 Volume 54, Issue 8 Pages 1345-1350
Dennis A. Clifford and Larry M. McGaughey

Abstract: An instrumental method based on adding a chemiluminescent NO detector to the flow system of a total oxygen demand (TOD) analyzer is described for measurement of the sum of all nitrogen forms other than N, in water. Typical analysis time is 2 min with a precision of 1% relative standard deviation (RSD) at 10 mg/L total nitrogen (TN) and a detection limit of 0.1 mg/L TN. Conversion of reduced nitrogen forms to NO is affected by the chemical form of the nitrogen, competition from carbonaceous oxygen demand (CTOD), and carrier gas oxygen concentration. At a temperature of 900°C, 1800 ppm O2 in N2 carrier gas, and 9.0 g of Pt gauze catalyst, the conversion to NO for 0-10 mg/L TN is apparently complete for all forms of nitrogen in the presence of up to 350 mg/L CTOD. Limited comparisons between wet-chemical and instrumental TN measurements on a tested wastewater showed excellent agreement.
Nitrogen, total Oxygen

"Continuous-flow Determination Of Free Chlorine In Water"
Anal. Chem. 1983 Volume 55, Issue 2 Pages 209-212
Toyoaki Aoki and Makoto Munemori

Abstract: A double-tube system, with an inner tube of microporous poly(tetrafluoroethylene) (PTFE) and an outer tube of PTFE, is proposed for the continuous flow measurement of free chlorine. Molecular chlorine, produced by mixing a sample with 1 N HCl in the outer tube, permeates microporous PTFE and dissolves in 0.1 N NaOH in the inner tube, changing it to ClO-. The inner solution flows into a UV detector, and ClO- is measured spectrophotometrically at 290 nm. UV signals are proportional to concentrations of free chlorine from 10^-5 to 10^-2 M. The lower limit of detection of free chlorine by this method is 2 x 10^-8 M. The time required for a 98% response is 3 min. Free chlorine is selectively measured even in the presence of MnO4-, CrO42-, combined chlorine, and heavy metals.

"Spectrophotometric Determination Of Metals At Trace Levels By Flow Injection And Series Differential Detection"
Anal. Chem. 1983 Volume 55, Issue 11 Pages 1669-1673
R. A. Leach, J. Ruzicka, and J. M. Harris

Abstract: The advantages of flow injection analysis for determination of trace metals are discussed.In the procedure described, de-gassed carrier and reagent solution are propelled at equal volume through the apparatus by pressure of He.Sample is injected (80 µL coiled loop) into the carrier stream, and the mixture flows through a delay coil to a point where the reagent stream is added.The mixture then flows through a reaction coil to the sample cell of the detection system (Kratos model 773 u.v. - visible spectrophotometer, optimized for 12 µL cells) and then to a matched reference cell. This differential detector system provides good baseline stability. The apparatus is applied to the determination of Fe [carrier stream 1 mM (NH4)2SO4; reagent stream (freed from Fe by passage through Amberlite XAD-2) 22 mM hydroxylammonium chloride - 18 mM Na acetate - 0.1 mM 1,10-phenanthroline; detection limit 0.7 ppb of Fe], Cu (carrier and reagent streams as for Fe, except that the reagent is 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline; detection limit 0.3 ppb) and Cr (carrier 0.1 M H2SO4; reagent stream 0.21 mM diphenylcarbazide in 0.1 M H2SO4; detection limit 1 ppb).
Chromium Copper Iron Spectrophotometry Amberlite

"Comparison Of Sample Injection Systems For Flow Injection Analysis"
Anal. Chem. 1983 Volume 55, Issue 14 Pages 2461-2464
Jeffrey J. Harrow and Jiri Janata

Abstract: In flow-injection anal. the technol. for injection can be improved by using a system based on 4 solenoid pinch valves, which is very inexpensive, precise, and compatible with either pumps or gas propulsion. The system was evaluated and compared to other methods for sample injection.
pH Conductometry Electrode Field effect transistor Apparatus Injection technique Method comparison Sample valve manipulation

"Flow Injection System For The Rapid And Sensitive Assay Of Concentrated Aqueous Solutions Of Strong Acids And Bases"
Anal. Chem. 1985 Volume 57, Issue 2 Pages 563-564
John A. Polta, In-Hyeong Yeo, and Dennis C. Johnson

Abstract: A pulsed amperometric detection method is described for the frequent quality-control monitoring of production streams of high-purity acids and bases, especially for strong acids and bases for which H+-selective glass electrodes lack sensitivity. The measurement of a small difference in concentration. between the reference and an injected solution is preferable to the quantitative determination of that difference over an extended range of concentration. Alternatively, the sample solution can be pumped as the carrier stream with occasional injections of standard reference solution. The theory of the method, based on the measurement of change of anodic current at a platinum electrode, is given.
Acids Bases Amperometry Electrode Process control

"Residual Aqueous Ozone Determination By Gas Diffusion Flow Injection Analysis"
Anal. Chem. 1985 Volume 57, Issue 9 Pages 1799-1803
Michael R. Straka, Gilbert Gordon, and Gilbert E. Pacey

Abstract: To determine residual 03 in treated water samples, an automated system of peristaltic pumps and injection valves was used to pass the aqueous test solution, at pH 2 (H2SO4), through a gas diffusion cell fitted with a micro-porous PTFE membrane, through which the 03 passed into (and decolorized) the colorimetric reagent. The decrease in absorbance was measured spectrophotometrically at 600 or 552 nm with use of K indigo trisulfonate or bis(terpyridyl)iron(II) reagent, respectively. Interference from Mn and H2O2 was eliminated, and that from Cl greatly reduced, by the diffusion technique. The indigo reagent was the more sensitive, and gave a detection limit of ~0.03 ppm of O3 and a rectilinear response up to 0.4 ppm.
Ozone Spectrophotometry Gas diffusion Interferences Tecator Teflon membrane

"Selective Determination Of Chlorine Dioxide Using Gas Diffusion Flow Injection Analysis"
Anal. Chem. 1985 Volume 57, Issue 14 Pages 2851-2854
David A. Hollowell, Gilbert E. Pacey, and Gilbert Gordon

Abstract: A Tecator Model 5020 flow injection analyzer. was used with a Tecator Chemifold V gas diffusion cell. The micro-porous membrane was a 0.45 µm pore-size PTFE membrane. The diffusion membrane separated the sample stream from the detector stream, and the ClO2 was detected at 359 nm with an ISCO spectrophotometer. The detection limit of ClO2 was 0.25 mg L-1 and the system was >550 times more selective for ClO2 than for Cl2. To further minimize the interference of Cl2, 0.83 M oxalic acid could be used in the acceptor stream, and this system had a detection limit of 0.45 mg L-1 of ClO2, but had 5400 times greater selectivity for ClO2 over Cl2.
Chlorine dioxide Spectrophotometry Gas diffusion Interferences Teflon membrane Tecator

"Dual Phase Gas Diffusion Flow Injection Analysis/hydride Generation Atomic Absorption Spectrometry"
Anal. Chem. 1986 Volume 58, Issue 2 Pages 502-504
G. E. Pacey, M. R. Straka, and J. R. Gord

Abstract: Flow injection manifolds are described in which HCl and NaBH4 enter the carrier stream and the resulting hydride diffuses through a PTFE membrane (7 cm x 1 mm; pore size 0.45 µm) supported by a nylon mesh in a modified Tecator gas diffusion cell. The hydride is then carried in a stream of H to a silica atomization cell of the type described by Dedina (Ibid., 1982, 54, 2097). The systems were used in the detection of As(III), one manifold providing for introduction of KI solution to reduce As(V). For 0.2 mL sample injections the limit of detection was 10 µg L-1 of As(III) and response was rectilinear up to 160 µg l-1. The principal advantage of the technique is the decreased interference by Co, Cu, Ni, Sb and Sn by comparison with the technique of Yamamoto et al. (Ibid., 1985, 57, 1382), while being simpler than the technique of Narasaki and Ikeda (Ibid., 1984, 56, 2059).
Arsenic(3+) Arsenic(5+) Spectrophotometry Gas diffusion Interferences Speciation Tecator Teflon membrane

"New Configuration For Construction Of PH Gradients In Flow Injection Analysis"
Anal. Chem. 1986 Volume 58, Issue 3 Pages 663-664
Angel Rios, M. Dolores Luque de Castro, and Miguel Valcarcel

Abstract: The configuration incorporates a second injection valve containing 4-(2-pyridylazo)resorcinol in the loop of the sample valve. The simultaneous injection of the two valves provides a reacting plug with three zones ensuring adequate resolution of the reagent mixtures. The system is applied to the spectrophotometric determination of Pb and V by flow injection by using a Pye Unicam SP6-500 instrument and a Hellma 178.12 QS flow cell. The new configuration ensures the establishment of the correct pH gradients and reagent concentration. at the centre of the injected sample.
Lead Vanadium Spectrophotometry Gradient technique pH gradient Tecator

"Liquid Chromatography With Electrochemical Detection And Coulometric Investigations Of Carbamate And [phenyl]urea Pesticides"
Anal. Chem. 1986 Volume 58, Issue 13 Pages 2777-2781
Q. Gordon Von Nehring, J. West Hightower, and James L. Anderson

Abstract: Selected phenylurea pesticides in a water matrix were determined without pre-treatment in 20 µL injections on a column (25 cm x 4.6 mm) of Hypersil SAS (5 µm), with methanol - [0.01 M Na2HPO4 - 0.015 M KH2PO4 - 0.1 M Na acetate buffer (pH 7)] (1:1) as mobile phase (1.0 mL min-1) and with electrochemical detection with a Kelgraf composite electrode at a potential of 1.15 V vs. silver - AgCl with 2 M KCl as electrolyte. Detection limits ranged from ~1 to 8 ng of pesticide injected (62 to 410 µg l-1). Flow injection coulometry was used for evaluation of electron transfer stoichiometry of oxidative electron transfer for carbamate, phenylurea and related pesticides in order to determine whether electrochemical detection in HPLC was influenced by electron transfer processes.
Pesticides, carbamate Pesticides, phenylurea HPLC Coulometry Electrode

"Dual Porous Electrode Membrane Cell For Detection Of Non-electroactive Species In Flowing Streams"
Anal. Chem. 1987 Volume 59, Issue 18 Pages 2260-2263
Antonin Trojanek and Stanley Bruckenstein

Abstract: A dual electrode detector capable of being used in flowing streams is described. One electrode generates a volatile reagent from a constituent present In the flowing stream, which then reacts with a dissolved analyte also present In the flowing stream. Excess volatile reagent diffuses through a non-wetting porous membrane to a second electrode at which the unreacted volatile reagent Is determined by constant potential electrolysis. The utility of this detector Is demonstrated by the determination of allyl alcohol with electrogenerated bromine In the range 23-697 ng of allyl alcohol.
Allyl alcohol Amperometry Electrode Apparatus

"Indirect Inductively Coupled Plasma Atomic Emission Determination Of Fluoride In Water Samples By Flow Injection Solvent Extraction"
Anal. Chem. 1990 Volume 62, Issue 22 Pages 2457-2460
Jamshid L. Manzoori and Akira Miyazaki

Abstract: An indirect determination of fluoride in water by inductively coupled plasma atomic emission spectrometry combined with flow injection coupled with solvent extraction is reported in this paper. A manifold for rapid determination of fluoride has been designed that uses a single coil for complex formation and extraction. The method involves the formation of lanthanum/alizarin complexone/fluoride complex and its extraction into hexanol containing N,N-diethylaniline. The concentration of fluoride is determined indirectly by introduction of the organic layer into the plasma and measurement of the emission intensity of the La II 333.75-nm line. The optimum experimental conditions for the determination are described. A coiled groove phase separator fitted with a grid and PTFE porous membrane was used in this work. The sampling rate was 36 samples per hour and the calibration graphs were linear from 0.03 to 1.3 µg/mL. The relative standard deviation found was 2.16% for 200 µL of 1µg/mL of fluoride. The method is selective and has been applied satisfactorily to the determination of fluoride in water samples.
Fluoride Spectrophotometry Sample preparation Complexation Phase separator Membrane Calibration Selectivity Indirect Solvent extraction

"Water Analysis"
Anal. Chem. 1991 Volume 63, Issue 12 Pages 301R-342R
Patrick MacCarthy, Ronald W. Klusman, Steven W. Cowling, and James A. Rice

Abstract: A review is presented including methods used and organic and inorganic analysis of water (>1000 references).
Organics, volatile Chemiluminescence HPLC GC Immunoassay Spectrophotometry Sample preparation Extraction Kinetic Solid phase detection Review

"Determination Of Boron In Light- And Heavy-water Samples By Flow Injection Analysis With Indirect UV - Visible Spectrophotometric Detection"
Anal. Chem. 1992 Volume 64, Issue 19 Pages 2201-2205
Therese Lussier, Roland Gilbert, and Joseph Hubert

Abstract: The sample was injected into a carrier stream of water, which was then merged with a stream of 0.29 mM chromotropic acid buffered at pH 7.4 with 0.5 M Na acetate (both 0.3 mL min-1). Detection was at 361.6 nm; the calibration graph was rectilinear from 40 to 6000 µg l-1. The coefficient of variation was 3% for 1000 µg L-1 and 1% at higher levels. The relative error was 6% and the detection limit was 8 µg l-1.
Boron Spectrophotometry Buffer Chromogenic reagent Indirect

"Water Analysis"
Anal. Chem. 1993 Volume 65, Issue 12 Pages 244R-292R
Patrick MacCarthy, Ronald W. Klusman, Steven W. Cowling, and James A. Rice

Abstract: The review, with many refs., covers water anal. for alkali and alkaline earth metals, NH4+, transition metals, anions, gases, organic compounds, volatile substances, pesticides, herbicides, fungicides, surfactants, detergents, organometallic compounds, including sampling, pre-concentration, extraction, biochemical methods, photometry, spectrophotometry, mass spectrometry, HPLC, gas and liquid chromatography, electrometric methods, and electrophoresis.
Organic compounds Spectrophotometry LC Mass spectrometry Voltammetry Sample preparation Extraction Review

"Speciation Of Methylmercury And Mercury(II) Using Baker's Yeast Biomass. Determination By Continuous-flow Mercury Cold Vapor Generation Atomic Absorption Spectrometry"
Anal. Chem. 1995 Volume 67, Issue 4 Pages 750-754
Yolanda Madrid, Carmen Cabrera, Teresa Perez-Corona, and Carmen Camara

Abstract: Baker's yeast (200 mg) was spiked with 2.5 g Hg(II) and 5 g and methylmercury and suspended in 1 mL 5% HEPES buffer of pH 7. The mixture was incubated at 37°C for 30 min and centrifuged at 5000 g for 5 min. The supernatant and separated biomass were both diluted to 25 mL with water and analyzed for Hg(II) and CH3Hg+ (I) in continuous flow by cold-vapor generation AAS. The effects of pH, incubation temperature and presence of foreign ions were investigated and reported. Under different experimental conditions selective separation of I and Hg(II) was possible. The method was used for the analysis of spiked water with recoveries >>83%.
Mercury(II) Methylmercury ion Spectrophotometry Speciation Volatile generation Volatile generation

"High-precision Determination Of 2H/1H In Hydrogen And Water By Continuous-flow Isotope Ratio Mass Spectrometry"
Anal. Chem. 1995 Volume 67, Issue 13 Pages 1992-1997
Simon J. Prosser and Charles M. Scrimgeour

Abstract: Simultaneous collection of 1H1H+ and 1H2H+ ions was achieved by using a Europa Scientific 20-20 mass spectrometer (illustrated) modified by having its flight tube 'flared' and an extra collector spur added. A magnetic field of 0.12 T was used with an accelerating potential of 4 kV. The method was applied to H2 gas and to water equilibrated with H2 in the presence of a Pt-on-alumina catalyst. Interference from H3+ could be corrected for by extrapolation to zero ion beam intensity. At natural abundance, isotopes in H2 and water could be determined in 2 min with a precision of ±0.15% and ±0.3%, respectively. No memory effect was observed. The technique should also be applicable to isotopes of C, N, O and S.
Hydrogen-1 Hydrogen-2 Mass spectrometry Isotope ratio Interferences

"Flow-through Determination Of Sulfate In Water Using Different Methods: A Comparison"
Fresenius J. Anal. Chem. 1980 Volume 300, Issue 4 Pages 273-276
H. F. R. Reijnders, J. F. van Staden, and B. Griepink

Abstract: Sulphate was determined in various kinds of environmental samples using a continuous-flow system, a flow-injection system or a flow-through titrimeter. The reagents in the three cases consisted basically of DMSA(III), KNO3 and Ba(ClO4)2. The results of the three methods were evaluated statistically. A comparison of the three methods is given. The advantage of the DSMA(III)-methods is shown in a comparison with the commonly used thorin method.
Sulfate Spectrophotometry

"Two-point Kinetic Simultaneous Determination Of Cobalt(II) And Nickel(II) In Aqueous Solution Using Flow Injection Analysis"
Fresenius J. Anal. Chem. 1983 Volume 314, Issue 4 Pages 386-390
D. Betteridge and Bernard Fields

Abstract: The different rates of the dissociation of the citrate complexes of cobalt(II) and nickel(II) at pH 9.25 are used as a basis for the two point kinetic assay of these ions at ppm levels in a flow injection analysis sytem. The reactions are followed by measuring the absorbance of complexes of the metal ions with 4-(2-pyridylazo)resorcinol (PAR) which are formed in a subsequent rapid reaction. EDTA is added to prevent interference from copper(II), manganese(II), zinc(II), chromium(III), lead(II) and vanadium(V) at 10 ppm. Determinations are made with errors of < 10% and at the rate of 30 samples per hour. The precision compares well with results for similar methods by other workers. These results and results by other workers show that this type of method suffers from poor precision in one analyte if the other analyte has a much higher concentration. It is however cheaper than others and has a greater sample throughput.
Cobalt(II) Nickel(II) Spectrophotometry Kinetic Simultaneous analysis

"Application Of Flow Injection Techniques For The Analysis Of Inorganic Anions"
Fresenius J. Anal. Chem. 1985 Volume 320, Issue 5 Pages 451-456
J. M&ouml;ller and B. Winter

Abstract: A review is presented, with 113 references. Some improvements in the determination of sulfur anions by flow injection analysis are also described. A survey of applications of flow injection analysis for the analysis of inorganic anions is given in form of a table. The turbidimetric determination of sulphate is improved by the intermittent addition of a wash solution via a separate pump. A comparison of results for the determination of sulphate in surface waters using the barium-methylthymol blue method and ion-chromatography shows good agreement. For the determination of sulphite a gas-diffusion technique is used. The method allows 90 injections/h and shows good reproducibility, 1% RSD for consecutive injections of standards at the 10 mg/l SO2-level. As the sample line is physically separated from the detection line, the method is insensitive to matrix effects from colored or turbid samples. Results for the determination of free and total sulphite in wine, beer and fruit juices are given.
Anions Sulfur compounds Sulfate Sulfite Spectrophotometry Gas diffusion Intermittent pumping Review Tecator

"Flow Injection Analysis By Using Acid-base Or Metal-ligand Buffers And Color-indicators"
Fresenius J. Anal. Chem. 1986 Volume 323, Issue 3 Pages 244-248
Nobuhiko Ishibashi and Toshihiko Imato

Abstract: Flow injection analysis is discussed, involving reaction of a sample with a buffer solution containing an indicator. The determination of HCl and NH3 is described by means of flow diagrams. The sample (~20 to 55 µL) is injected into a flow of water (1.5 mL min-1) which is mixed with a flow (1.5 mL min-1) of 0.1 M acetate buffer (pH 4.8) containing 20 µM-methyl red, and the peak height of the change in absorbance at 520 nm is evaluated by means of calibration graphs. Similarly a sample of CaCl2 and MgCl2 (130 µL) was injected into a flow (1 mL min-1) of water, which was combined with a flow (1 mL min-1) of 5 mM EDTA (pH 9.5), which in turn was combined with a flow (0.9 mL min-1) of 10 mM nitrilotriacetic acid, 0.2 mM Calmagite [pH 9.5; 3-hydroxy-4-(6-hydroxy-m-tolylazo)naphthalene-1-sulfonic acid] and 10 mM MgCl2, with measurement at 535 nm.
Hydrogen chloride Ammonia Calcium Chloride Magnesium Spectrophotometry Chelation Theory

"Optimization Of Ion-chromatographic Trace Analysis For Heavy And Alkaline-earth Metals By Post-chromatographic Derivatization"
Fresenius J. Anal. Chem. 1987 Volume 327, Issue 5-6 Pages 503-508
Da -ren Yan, und Georg Schwedt

Abstract: Six metal ions (Fe(III), Cu, Zn, Co, Fe(II) and Mn in elution order) can be separated in 2.5 min by HPLC on a glass column (10 cm x 3 mm) packed with the strong-acid silica gel cation exchanger BT V TM (10 µm; Biotronik) and operated with a mobile phase (2 mL min-1) of 0.25 M tartrate (pH 2.45). A mixture containing 11 ions (additionally Pb, Ni, Cd, Ca and Mg) was separated in 24 min by HPLC on a glass column (20 cm x 4 mm) packed with BT V TM and operated with a mobile phase (1.3 mL min-1) of 0.1 M tartrate (pH 3.05). Detection (at 490 nm) followed post-column derivatization (60°C, 0.25 mL min-1) with a reagent containing 1 mM 4-(2-pyridylazo)resorcinol, 2 M NH3 (pH 11) and, for the 11-elements separation, 0.25 mM ZnEDTA. Detection limits were 1 to 2 ppb although, with pre-concentration. of water samples on a column (5 cm x 3 mm) packed with BT V TM, metals in concentration. 1 part in 1012 could be determined.
Metals, alkaline earth Metals, heavy Iron(III) Copper Zinc Cobalt Iron(2+) Manganese HPIC Spectrophotometry Heated reaction Post-column derivatization Preconcentration Speciation Optimization

"Flow Injection Extraction In Theory And Practice"
Fresenius J. Anal. Chem. 1988 Volume 329, Issue 6 Pages 660-662
Bo Karlberg

Abstract: Flow injection schemes involving solvent extraction are reviewed, with examples. Procedures are given for the extractions of caffeine from beverages, anionic surfactants from aqueous samples, codeine from drugs, bitterness compounds from beer, and phenol from water. The organic extractant is 2,2,4-trimethylpentane (for beer) or CHCl3 (others). A typical system is characterized by low comsumption of organic phase (0.5 to 2 mL per sample), low sample volume (20 to 200 µL) and high sample throughput (45 to 120 h-1). (9 references).
Bittering compounds Caffeine Codeine Phenol Surfactants, anionic Sample preparation Extraction Review Tecator Theory

"Spectrophotometric Flow Injection Analysis Of Formaldehyde In Aqueous Solutions Using 3-methyl-2-benzothiazolinone Hydrazone"
Fresenius J. Anal. Chem. 1993 Volume 347, Issue 12 Pages 491-494
R. Goebel, A. Krug and R. Kellner

Abstract: Samples (180 µL) were injected into a carrier stream (1 ml/min) of 0.1 M Tris hydrochloride buffer of pH 7, which was mixed with a stream (1 ml/min) of 1 mM 3-methyl-2-benzothiazolinone hydrazone in a 200 cm mixing coil. The resulting stream was mixed with a stream (1 ml/min) of FeCl3 solution (0.2 g/l in 0.4 M HCl) in a 250 cm mixing coil, before the absorbance was measured at 635 nm. The flow system (diagram given) was maintained at 60°C. The calibration graph was linear from 0.15-15 mg/l of formaldehyde with RSD of 2.3% (at 3 mg/l) and 5.1% (at 0.3 mg/l); no detection limit is given. Benzaldehyde, NaCl, glucose and urea (up to 20 mM), ammonium sulfate, sodium nitrate, sodium phosphate and sodium carbonate (up to 5 mM), and methanol, ethanol and acetone did not interfere. Acetaldehyde and propionaldehyde showed positive interference at concentrations of 1 mM and 5 mM, respectively. Sodium nitrite interfered strongly at concentrations of >1 mM.
Formaldehyde Spectrophotometry Interferences

"Evaluation Of Noisy FIAs Using The Cross-covariance Function"
Fresenius J. Anal. Chem. 1994 Volume 348, Issue 4 Pages 255-257
Klaus Doerffel Contact Information, Jens Dost and Helmut M&uuml;ller

Abstract: Periodic signals at regular intervals, accompanied by noise as in FIA, were combined with a sequence of rectangular signals without noise and the cross-covariance function was determined by simulation, assuming the analytical signal to be a triangle with a symmetrical or distorted base. The results indicated that the detection limit could be lowered. The finding was confirmed by the injection of Cu(II) solution (0-400 ppb) into an water carrier (5 ml/min), with AAS detection at 327.4 nm. Application of the algorithm decreased the detection limit by about half, e.g., with use of two analytical signals, from 59-33 ppb.
Copper(II) Spectrophotometry

"Flow Injection Analysis - Spectrophotometric Determination Of 8-hydroxyquinoline With P-aminophenol"
Fresenius J. Anal. Chem. 1996 Volume 354, Issue 2 Pages 216-220
B. A. Hasan A, K. D. Khalaf A, A. Morales-Rubio A, M. de la Guardia

Abstract: A 10 mL portion of 1 M NaOH was added to 8-hydroxyquinoline (quinolin-8-ol; I) prepared in HCl of pH 3, or in KCl/H3BO3/NaOH buffers of pH 8 or 10 and the total volume was diluted to 25 mL. Streams (3.2 ml/min) of p-aminophenol (PAP) (100 µg/ml) and 0.004 M KIO4 were mixed in a reactor coil (45 cm x 0.8 mm i.d.) and the benzoquinoneimine, formed in situ fed into a second reactor coil (400 cm x 0.8 mm i.d.) with 0.4 M NaOH (3.2 ml/min) into which a 500 µL portion of I in an appropriate buffer had been injected. The resultant indophenol dye (structure illustrated) was measured at 610 nm in a 50 µL flow cell (1 cm path). The calibration graph was linear from 2-8 µg/ml I and the detection limit was 7.6 ng/ml. The RSD (n = 4) was 0.06% for 4 µg/ml I. Recoveries of 98-102% were obtained at pH 3, 8 or 10. Sensitivity is lower (ε = 9500) for the reaction of I with PAP than reported for batch procedures which employ reactions of I with orthanilic acid (ε = 26 500) or diazotized 4-aminoacetophenone (ε = 33 700).
8-Quinolinol Spectrophotometry Buffer

"A Flow Analysis System With An Amperometric Detector For The Determination Of Hydrogen Sulfide In Waters"
Fresenius J. Anal. Chem. 1996 Volume 354, Issue 2 Pages 169-172
Paul Jeroschewski and Sabine Braun

Abstract: Hydrogen sulfide (I) was liberated from aqueous samples with an acidic carrier solution and the mixed streams subsequently mixed with N2 (1.78 ml/min) prior to passage through a coiled glass capillary (60 cm x 2 mm i.d.) extraction unit. These dimensions were necessary to ensure an equilibrium exchange of I from the liquid phase to a series of N2 bubbles (28 µL) in accordance with Henry's law. The liquid stream and N2 bubbles passed into an electrochemical sensor (described and illustrated) constructed to ensure that only H2S in the gas phase was able to permeate through a microporous PTFE membrane into alkaline ferricyanide. The current necessary to re-oxidize the resultant ferrocyanide depended directly on the concentration of I. The dynamic range, under the above conditions, was 1-750 µM-I with an RSD of 3%.
Hydrogen sulfide Amperometry Teflon membrane Gas diffusion Indirect

"Flow-through Sensor Based On Derivative Synchronous Fluorescence Spectrometry For The Simultaneous Determination Of Pyrene, Benzo(e)pyrene And Benzo(ghi)perylene In Water"
Fresenius J. Anal. Chem. 1996 Volume 354, Issue 3 Pages 291-295
P. Ca&ntilde;izares and M. D. Luque de Castro

Abstract: A flow-through/first derivative synchronous spectrofluorimetric sensor for the determination of PAH has been described. This sensor has been used for the simultaneous determination of PAH mixtures (pyrene, benzo(e)pyrene and benzo(ghi)perylene). Linear calibration ranges between 10 and 500 ng/ml with acceptable precision (repeatability, expressed as relative standard deviation, smaller than 4.6%, and sampling frequency of 12 h-1) have been obtained. The method has been applied to the determination of the target analytes in spiked water samples with excellent results (recoveries between 94 and 108%).
Benzo(e)pyrene Pyrene Benzo(ghi)perylene Fluorescence Sensor

"Speciation Of Arsenic In Water Samples By High Performance Liquid Chromatography-hydride Generation-atomic Absorption Spectrometry At Trace Levels Using A Post-column Reaction System"
Fresenius J. Anal. Chem. 1996 Volume 354, Issue 3 Pages 344-351
J. Stummeyer, B. Harazim and T. Wippermann

Abstract: Anion-exchange HPLC has been combined with hydride generation - atomic absorption spectrometry (HG-AAS) for the routine speciation of arsenite, arsenate, monomethylarsenic acid and dimethylarsinic acid. The sensitivity of the AAS-detection was increased by a post-column reaction system to achieve complete formation of volatile arsines from the methylated species and arsenate. The system allows the quantitative determination of 0.5 g/l of each arsenic compound in water samples. The stability of synthetical and natural water containing arsenic at trace levels was investigated. To preserve stored water samples, a method for quantitative separation of arsenate at high pH-values with the basic anion-exchange resin Dowex 1 x 8 was developed.
Arsenic HPLC Spectrophotometry Post-column derivatization Volatile generation Speciation Volatile generation

"Chemiluminescence Flow System For The Determination Of Iron(II) And Iron(III) In Water"
Fresenius J. Anal. Chem. 1998 Volume 360, Issue 1 Pages 130-132
W. Qin A, Z. J. Zhang A, F. C. Wang

Abstract: A novel chemiluminescence (CL) flow system has been developed for the sequential determination of Fe(II) and Fe(III) in water. Fe(II) was detected by its catalytic effect on the CL reaction between luminol immobilized on an anion exchange resin column and dissolved oxygen; Fe(III) was determined by difference measurement after on-line conversion to Fe(II) in a reducing mini-column packed with Cu plated Zn granules. For both ions, the calibration graph was linear in the range 1 2 10^-9 to 1 2 10^-6 g/mL, and the detection limit was 4 2 10^-10 g/mL. A complete analysis could be performed in 1.5 min with a relative standard deviation of less than 5%. The system could be reused for over 200 times and has been applied successfully to the determination of Fe(II) and Fe(III) in natural water samples.
Iron(2+) Iron(III) Chemiluminescence

"Dual Stage Preconcentration System For Flame Atomic Absorption Spectrometry Using Flow Injection Online Ion-exchange Followed By Solvent Extraction"
Fresenius J. Anal. Chem. 1998 Volume 360, Issue 2 Pages 156-160
Guanhong Tao and Z. Fang

Abstract: A dual stage pre-concentration system based on flow injection online ion-exchange and solvent extraction was developed for flame atomic absorption spectrometry. Pb was taken as a model trace element. A column packed with Amberlite IRC-718 cation exchanger was incorporated into the FI manifold. The analyte was retained on the column by time-based sample loading and eluted by 1 mol/L HNO3. The eluate was subsequently merged with KI and tetrabutylammonium bromide. Pb was extd. online into iso-Bu Me ketone as the ion-pair formed between the iodo plumbate anion and tetrabutylammonium cation. The organic phase was separated from the aqueous phase by a gravity phase separator. 50 µL of concentrate was introduced into the nebulizer-burner system of the spectrometer. An enhancement factor of 550 was achieved with a 30 mL sample consumption at a sampling frequency of 30/h. The RSD was 2.4% at 10 µ/L level and the detection limit was 0.3 µg/L (3s). The method was successfully applied to the determination of Pb in water samples.
Lead Ion exchange Spectrophotometry Preconcentration Amberlite MIBK Ion pair extraction Phase separator

"Flow Injection Spectrofluorimetric Determination Of Ethylenethiourea"
Fresenius J. Anal. Chem. 1998 Volume 362, Issue 4 Pages 399-403
Tom&aacute;s P&eacute;rez-Ruiz, Carmen Mart&iacute;nez-Lozano, Virginia Tom&aacute;s, Antonio Sanz, Jes&uacute;s Mart&iacute;n

Abstract: A flow injection configuration is proposed for the fluorimetric determination of ethylenethiourea. The procedure is based on the inhibitory effect of ethyl-enethiourea on the oxidation of thiamine to thiochrome by Hg(II). A linear calibration graph was obtained between 0.1-2.0 µg mL-1, with a sampling rate of 40 samples/h and a relative standard deviation of 1.11%. The usefulness of the method was tested for the determination of ethylenethiourea residues in water, milk, potatoes, pear, grape, and apple.
Ethylenethiourea Fluorescence Indirect

"Laser-based Refractive-index Detection Using The Sheath-flow Cuvette"
Microchim. Acta 1986 Volume 90, Issue 5-6 Pages 351-357
Yung-Fong Cheng and Norman J. Dovichi

Abstract: Light (632.8 nm) from a linearly polarized 2-mW He - Ne laser was focused by a 2.5-cm-focal length lens to traverse an Ortho model 300-051100 sheath-flow cuvette in which the sample stream was injected along the axis of a sheath stream under laminar-flow conditions, and was detected by a 1-mm2 Si photodiode connected through a current-to-voltage converter to a digital voltmeter. The cuvette was located ~1.5 cm past the beam waist (waist spot size ~15 µm) and near the centre of the beam axis. A set of diffraction fringes was formed at the extremities of the field by interaction of the beam with the body of the cuvette, the intensity at the centre of the fringe system being markedly perturbed by the presence of the sample stream. The detection limit for a 20 µm-radius sample stream corresponded to a refractive index difference of 3 x 10^-6, i.e., ~15 pg for glycerol. Application to flow injection analysis and gradient-elution HPLC is envisaged.
HPLC Refractometry Apparatus Cuvette Laser Refractive index Photodiode

"Flow Injection Spectrophotometric Determination Of Cresol Compounds In Water By Reaction With P-aminophenol"
Microchim. Acta 1993 Volume 112, Issue 1-4 Pages 99-111
K. D. Khalaf, B. A. Hasan, A. Morales-Rubio and M. de la Guardia

Abstract: For FIA, a stream of aqueous p-aminophenol solution was merged with a stream of 4 mM KIO4, passed through a mixing coil (45 cm x 0.8 mm i.d.) and merged with a carrier stream of 60 mM NaOH into which the sample had been injected. After passage through a reaction coil (800 cm x 0.8 mm i.d.) the absorbance of the mixture was measured at 614 nm for o-cresol (OC) and 632 nm for m-cresol (MC). All flow rates were 2.5 ml/min. Stopped-flow and batch methods were also studied and diagrams are given of the manifolds used for stopped-flow and FIA determinations. The batch procedure required 22 min for full color developement while the stopped-flow method required only 12 min. The FIA method gave linear calibration graphs up to 4.8 and 9.6 µg/ml for OC and MC, respectively, with corresponding detection limits of 80 and 140 µg/l, RSD of 0.7% for 2.4 µg/ml of OC and 0.5% for 6.4 µg/ml of MC and recoveries of >90%. The stopped-flow procedure gave improved sensitivity with detection limits of 10 and 30 µg/l for OC and MC, respectively, however sample throughput was lower than that of the FIA method (80/h).
2-Cresol 3-Cresol Spectrophotometry Stopped-flow Method comparison

"Spectral And Non-spectral Interferences In Inductively Coupled Plasma Mass Spectrometry"
Microchim. Acta 1995 Volume 119, Issue 3-4 Pages 277-286
Richard F. J. Dams, Jan Goossens and Luc Moens

Abstract: An overview is presented on the identification and elimination of interferences in ICP-MS. Elimination of spectral interferences by anion exchange, matrix modification and mathematical correction are discussed. Calibration methods, adapted sample preparations and flow injection techniques for the elimination of nonspectral interferences are then considered. Applications of the correction methods to the analysis of water, soil, sewage, urine, serum and wine are described. (50 references).
Mass spectrometry Sample preparation Interferences Matrix removal Review

"Automated Determination Of Sulfate By Continuous Precipitation - Filtration Of Lead Sulfate"
Microchem. J. 1989 Volume 39, Issue 1 Pages 71-75
Zorro, J.;Gallego, M.;Valcarcel, M.

Abstract: The sample, containing 2 to 20 µg mL-1 of SO42- at pH 8.5 to 9.5, was mixed with a carrier stream of Pb2+ (300 µg mL-1 in aqueous 20% ethanol) of pH 4.2 to 5.2. The PbSO4 produced was filtered off and the residual Pb2+ (and hence the amount pptd. by SO42-) was determined by AAS at 283.3 nm with an air - acetylene flame. The detection limit was 1 µg mL-1, and at 10 µg mL-1, the coefficient of variation (n = 11) was 3.0%. The sampling rate was ~60 h-1. The method should be applicable to water samples.
Sulfate Spectrophotometry Filter Precipitation Indirect

"Flow Injection Spectrophotometric Catalytic Method For The Determination Of Ruthenium(III)"
Microchem. J. 1993 Volume 48, Issue 2 Pages 210-214
Almuaibed A. M. and Townshend A.

Abstract: Aqueous sample solution (20 µL) was injected into a carrier stream of 0.4 mM KIO4 and 0.7 M HClO4 which merged with a stream of 40 µM-ferroin and passed through a reaction coil (150 cm); the decrease in absorbance was monitored at 505 nm. The procedure was performed at room temperature and a flow rate of 2.5 ml/min was used throughout. The calibration graph was rectilinear for 0.12 µg/ml of Ru(III) with a sample throughput of 50/h and the detection limit was 5 g/l. The RSD (n = 10) for 60 ng/ml of Ru(III) was 3%. Results compared very well with those obtained by a batch method. The interference effects of some metal ions are discussed.
Ruthenium(III) Spectrophotometry Catalysis Interferences Method comparison

"A Novel Flow Injection System For Simultaneous Determination Of Nitrate And Nitrite Based On The Use Of A Zinc Reductor And A Bulk Acoustic Wave Impedance Detector"
Microchem. J. 1998 Volume 59, Issue 3 Pages 341-350
Xiao-Li Su, Po Chen, Xiao-Ge Qu, Wan-Zhi Wei and Shou-Zhuo Yao

Abstract: A novel flow injection system was developed for the simultaneous determination of nitrate and nitrite present in water, foodstuffs, and human saliva. The system is based on the use of a Zn-filled reduction column and a bulk acoustic wave impedance sensor (BAWIS) as detector. With water as carrier stream, both nitrate and nitrite are converted online to NH3, whereas with sulfamic acid, only nitrate is converted to NH3. The NH3 formed diffuses across a PTFE membrane and is trapped in an acid stream causing a change in the solution conductance, which was monitored by a BAWIS detector. At a throughput of ~60 h-1, the proposed system exhibited a linear response to the concentration. of nitrate and nitrite from 2.5 µM to 1.00 mM, with detection limits of 1.7 and 1.8 µM, respectively, and the relative standard deviation of the peak heights (n = 6) ranged between 0.83 and 1.75% for the entire working range. In anal. of real samples, the simultaneous determination of nitrate and nitrite was achieved by the proposed method with a simple change of the carrier stream between water and sulfamic acid, and the results agreed well with those of conventional colorimetry. (c) 1998 Academic Press.
Nitrate Nitrite Conductometry Sensor Gas diffusion Reduction column Teflon membrane Simultaneous analysis

"Speciation Of Thallium By Flow Injection Analysis With Spectrofluorometric Detection"
Microchem. J. 1998 Volume 60, Issue 1 Pages 75-83
Ali A. Ensafi and B. Rezaei

Abstract: A flow injection configuration is proposed for the speciation and determination of Tl(I) and Tl(III) in aqueous media by spectrofluorometric detection. Tl(I) can be determined by measuring its fluorescence as TlCl32-. Tl(III) also is determined after the rapid reduction of this ion by hydrazine into Tl(I). The construction of a suitable valve in the manifold allows the successive determination of these ions at concentrations ≥10-7 M. The effect of potential interfering species on the determination was studied. The method was successfully applied to the determination of Tl in synthetic and real samples.
Thallium(I) Thallium(III) Fluorescence Valve Interferences Speciation

"Continuous-flow Determination Of Residual Aqueous Ozone With Membrane Separation-chemiluminescent Detection"
Anal. Lett. 1988 Volume 21, Issue 5 Pages 835-842
Aoki, T.

Abstract: Ozone in aqueous solution was extracted in a concentric permeation tube system (50 cm long) in which the solution flowed through the inner microporous PTFE tube (2.0 mm i.d., 2.8 mm o.d., pore size 3.5 µm) and ozone permeated into the outer PTFE tube (4.0 mm i.d., 5.0 mm o.d.) where air was flowing at 600 mL min-1. The air was fed through a Nafion permeation tube for drying (H2O interfered with ozone measurement) and then mixed with a stream (32 mL min-1) of 7.25% ethylene in N, and the absorbance of the chemiluminescent product was measured at 260 nm. A stable signal was attained in 1.5 min. A rectilinear calibration graph was obtained for 8 ppb to 9.5 ppm of ozone and, at 0.2 ppm, the coefficient of variation (n = 4) was 3.5%. Phthalate, sulfophthalate, Cl, Br, Cr(VI) and Mn(VII) did not interfere.
Ozone Chemiluminescence Nafion membrane Interferences Teflon membrane Permeation tube

"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 Chemiluminescence Column Solid phase reagent Electrochemical product conversion Immobilized enzyme

"Flow Injection Determination Of Chloride Ions With Spectrophotometric Detection"
Anal. Lett. 1997 Volume 30, Issue 15 Pages 2847-2858
Mihaela Cheregi; Andrei F. Danet

Abstract: A single-line FIA system with a stream-sample splitting device for chloride determination is presented. The analytical method is based on the Fe3+/Hg(SCN)2/Cl- system and the absorbance of the red Fe(SCN)2+ species monitored spectrophotometrically at 480 nm. Using a stream-sample splitting device, the recorded signal is composed of two merged peaks. Three calibration curves were obtained, once injecting the standard solution series, two using the maximum heights of P1 and P2 peaks and one using the height of T trough. The FIA system showed three linear responses to the concentration of chloride in the ranges 10^-100 ppm (P1)-, 10^-500 ppm (P2) and 20-1000 ppm (T), respectively. Also, it was capable of detecting chloride ions in different types of water with a throughout of 15 samples h-1 and the RSD for 240 ppm of Cl- (n = 10) were 1.67% (P1); 2.38% (P2) and 1.23 % (T), respectively. The interference of several ions (commonly found in water) on the FIA outputs was investigated.
Chloride Spectrophotometry Interferences Sample splitting

"Rapid Determination Of Warfarin By Sequential Injection Analysis With Cyclodextrin-enhanced Fluorescence Detection"
Anal. Lett. 1998 Volume 31, Issue 5 Pages 891-901
Lian X. Tang; Frederick J. Rowell

Abstract: A procedure for rapid and reproducible measurement of warfarin was described. The method is based on a computer-controlled sequential injection analysis (SIA) system. The formation of drug inclusion complexes with β-cyclodextrin in aqueous solution was used to obtain fluorescence enhancement. Cyclodextrin and warfarin solutions were sequentially injected and mixed within seconds using the automated system and the fluorescence was monitored immediately. The calibration curve was linear over the measured concentration. range of 0.1 to 1 µg/mL (r2 = 0.998, n = 5) with a limit of detection of 0.02 µg/mL. The measurement was fast with response time of 20 s, and was also reproducible with coefficient of variation at 1.5%(n=10) at a concentration. of 0.5 µg/mL. Water samples spiked with warfarin were successfully measured using the method.
Warfarin Fluorescence Sequential injection Complexation

"Simultaneous Measurements Of Trace Metals By Adsorptive Stripping Voltammetry"
Electroanalysis 1989 Volume 1, Issue 3 Pages 229-234
Joseph Wang*, Jawad Mahmoud, Javad Zadeii

Abstract: Simultaneous measurements of trace metals, based on adsorptive stripping voltammetry of their chelates with dihydroxyazo dyes, are demonstrated. Variables affecting the resolution between neighboring chelate peaks, including the ligand and its concentration, pH, adsorption time and potential, concentration ratio, and scan rate, are assessed. Adequate resolution is demonstrated for more than 10 pairs of metals, present at the ppb level. Possible changes in peak heights, associated with competition for the complexing ligand and/or coadsorption effects, are explored. Different concentration ratios of the mixture components can be tolerated. Applicability to seawater analysis is illustrated.
Uranium Titanium Aluminum Iron Molybdenum Vanadium Thorium-232 Nickel Cobalt Manganese Copper Gallium Zinc Tin Voltammetry

"Peroxidase-modified Carbon-paste Microelectrode As Amperometric FI-detector For Peroxides In Partial Aqueous Media"
Electroanalysis 1996 Volume 8, Issue 11 Pages 1014-1019
Ionel C. Popescu, Elisabeth Cs&ouml;regi, Lo Gorton

Abstract: Portions (100 mg) of graphite powder were treated for 2 h at 4°C with 400 µL 0.1 M phosphate buffer (pH 8) containing 2 mg horseradish peroxidase (HP) or fungal peroxidase (from Arthromyces ramosus) and 10 mg lactitol. The mixtures were dried under reduced pressure, mixed with 40 µL paraffin oil, and the resulting pastes packed into PTFE tubes (10 cm x 0.5 mm i.d.) to give peroxidase/lactitol-modified C-paste electrodes. These were used in a flow injection system (details given) with Ag/AgCl quasi-reference and counter electrodes. For each type of peroxidase, enzymatic activity was higher for the detection of H2O2 (I) than for 2-butanone peroxide (II) regardless of the solvent composition. Detection limits were 0.1 µM I and 0.3 µM II, obtained with a HP-modified electrode. For both types of peroxidase the analytical sensitivity decreased according to solvent composition in the order water > aqueous 10% acetonitrile > aqueous 10% methanol (results presented).
Hydrogen peroxide Electrode Amperometry

"The Coulometric Determination Of Chemical Oxygen-demand"
Electroanalysis 1997 Volume 9, Issue 4 Pages 279-283
Kim L. Pamplin, Dennis C. Johnson*

Abstract: The chemical oxygen demand (COD) of solutions containing various organic compounds is calculated from the net faradaic charge (Q(net)) estimated for the total electrolytic oxidation of Cr-III generated during oxidative degradation of the organic compounds in acidic media containing excess Cr-VI. Values of Q(net) for conversion of Cr-III to Cr-VI are estimated from the linearized chronoamperometric data plotted as ln i(tot,t) vs. t. This procedure is preferred over determinations of Q(net) from the total integrals of i(tot) over the entire electrolysis period because of large errors that can result from uncertainty in the background current (i(bkg)) for t --> infinity. The proposed coulometric procedure offers the benefit that reagent solutions can be reused, thereby minimizing the need for disposal of wastes containing toxic Cr-VI. This procedure was applied in a single digest solution for consecutive determinations of COD. Average COD values for potassium acid phthalate and glucose were 103.8 % (s = 6.0, N = 10) and 100.2 % (s = 4.2, N = 11), respectively, based on the theoretical degradation to CO2. In comparison for these same samples, an EPA approved method, based on colorimetric determination of Cr-III, gave COD values of 101.4 % (S = 1.4, N = 5) and 100.1 % (s = 1.4, N = 5) of the theoretical. Statistical tests indicate no significant difference in the COD values determined for these compounds using the coulometric and EPA methods. 30 References
Chemical oxygen demand Coulometry Method comparison Redox

"A Photo-cured Coated Wire Potassium Ion-selective Electrode For Use In Flow Injection Potentiometry"
Electroanalysis 1997 Volume 9, Issue 11 Pages 813-817
Peter W. Alexander*, Telis Dimitrakopoulos, D. Brynn Hibbert

Abstract: A potassium ion selective electrode (ISE) is reported based on the epoxyacrylate polymer prepared from o-nitrophenyl octyl ether as the plasticizer and 2,2'-bis <3,4-(15-crown-5-)-2-nitrophenylcarbamoxymethyl>tetradecane (BME-44) as the ionophore. Several different electrodes were studied by photo-curing different membranes onto a silver wire (0.8 mm i.d.), and the response characteristics were evaluated. The membranes prepared exhibited strong adhesion to the metal substrate and showed improved mechanical strength compared to poly(vinyl chloride)-based membranes. The sensor exhibited Nernstian response over a log-linear range of between 0.01 mM and 100 mM, and was selective against the common interfering ions. Fast response reaching 90% of steady-state value in 5 s makes this sensor applicable for flow injection potentiometry measurements. The potassium ISE allows for accurate determinations of potassium in various water samples by flow injection potentiometry. 23 References
Potassium Potentiometry Electrode Electrode Electrode Selectivity Interferences

"Microelectrode Procedures For The Determination Of Silicate And Phosphate In Waters Fundamental-studies"
Electroanalysis 1997 Volume 9, Issue 17 Pages 1311-1317
Neil G. Carpenter, Alexia W. E. Hodgson, Derek Pletcher *

Abstract: The voltammetry of the molybdosilicate and molybdophosphate complexes, formed by the addition of hexafluorosilicate and phosphate to an acidic sodium molybdate solution, have been defined at gold microdisk electrodes. It is shown that the reaction conditions influence both the kinetics of formation of the complexes and their voltammetry. It is possible to find conditions where the steady state amperometric response of the Au microdisk electrodes allows a rapid and convenient method for the determination of silicate and phosphate at concentrations in the range 1-1000 µM. 30 References
Silicate Phosphate Amperometry Electrode Electrode Electrode Kinetic Optimization Complexation Steady state

"A Six Sensor Array Of Coated-wire Electrodes For Use In A Portable Flow Injection Analyzer"
Electroanalysis 1998 Volume 10, Issue 10 Pages 707-712
Peter W. Alexander*, Telis Dimitrakopoulos, D. Brynn Hibbert

Abstract: An array of 5 photo-cured epoxydiacrylate membrane electrodes incorporating ionophores and a Ag/AgCl wire electrode used as a chloride sensor were all used simultaneously in a previously reported multielectrode flow cell and in a portable flow injection analyzer described by P. Alexander et al. (1996). Photo-cured coated-wire electrodes for NH4+, Ca2+, H+ (pH), NO3-, and K+ and Ag/AgCl wire-based chloride electrode were developed for remote-site monitoring. The photo-cured membranes prepared exhibited strong adhesion to the metal substrate and showed improved mech. strength compared to PVC-based membranes. Each sensor in the present electrode-array exhibited near-Nernstian response over a log-linear range from 0.1-10 mM with detection limits of 0.01 mM in the flow injection potentiometric mode. The flow injection cell was capable of determining the respectively. ions in various water samples and the results were in good agreement with comparative anal. methods.
Chloride Ammonium Calcium pH Nitrate Potassium Electrode Electrode Electrode Potentiometry Method comparison

"Determination Of N-methylcarbamates And N-methylcarbamoyloximes In Water By High Performance Liquid Chromatography With The Use Of Fluorescence Detection And A Single O-phthalaldehyde Post-column Reaction"
J. Chromatogr. A 1993 Volume 643, Issue 1-2 Pages 317-320
Verne A. Simon, Karl S. Pearson and Anne Taylor

Abstract: Water was filtered and injected directly on to a column (15 cm x 4.6 mm) of HS-C18 (3 µm), equipped with a guard column of C18 bonded-phase. Gradient elution (1 ml/min) was effected with aqueous acetonitrile from 5-20% in 13 min, followed by 65% for 15 min and 5% for 2 min (held until the next injection). Fluorescence detection was carried out at 460 nm (excitation at 340 nm). Single-stage post-column derivatization was performed by merging the eluate with a filtered and degassed solution containing o-phthalaldehyde and Thiofluor in 0.05 M NaOH at 0.1 ml/min. The reaction was carried out at 95°C in a 500 µL reaction coil. The reagent was stable for up to 30 injections and led to a faster, simpler operational procedure than the traditional two-stage method without any loss in sensitivity. Detection limits ranged from 0.5-1.2 µg/l, recoveries ranged from 99.4-102% and the RSD (n = 7) ranged from 1.8-3.1%. The calibration graph was rectilinear over the concentration. ranged tested. No interference or other difficulties were encountered with this method.
Carbamates, N-methyl Carbamoyloximes, N-methyl HPLC Fluorescence Post-column derivatization Heated reaction Interferences

"Methods Of Analysis Of Polar Aromatic Sulfonates From Aquatic Environments"
J. Chromatogr. A 1996 Volume 733, Issue 1-2 Pages 473-489
Thorsten Reemtsma

Abstract: Methods for the analysis of aromatic sulfonates, such as linear alkylbenzene sulfonates (LAS) and (amino- and hydroxy-substituted) benzene and naphthalene sulfonates, from aqueous media are reviewed. All analytical steps including the extraction from water, clean-up from co-extracted substances, chromatographic separation and detection, and methods of identification of these compound classes are described and discussed. The techniques employed are solid-phase extraction, various modes of high performance liquid chromatography (HPLC), capillary electrophoresis, gas chromatography (GC), GC-mass spectrometry, liquid chromatography-mass spectrometry, continuous-flow- and flow injection mass spectrometry, and spectroscopic methods. A remarkable gap becomes obvious between novel analytical methods developed with standard mixtures and those methods readily employable for environmental analysis. Finally, suggestions for future analytical developments are given.
Sulfonamides HPLC Mass spectrometry Review

"Electroinjection Analysis. Concept, Mathematical Model And Applications"
J. Chromatogr. A 1997 Volume 772, Issue 1-2 Pages 115-127
Victor P. Andreev*, Natalia B. Ilyina, Elena V. Lebedeva, Alexandr G. Kamenev and Nicolai S. Popov

Abstract: Mathematical models for the mutually complementary techniques of electroinjection analysis (EIA; a combination of FIA and CZE; Talanta, 1996, 43, 909) and electrophoretically mediated microanalysis (EMMA; Patterson et al., J. Chromatogr., A, 1996, 732, 119) are presented. EIA and EMMA are demonstrated by the determination of Cr(VI) and Co2+, respectively, in water (detection limits 1.4 and 1 ng/ml, respectively).
Cobalt(II) Chromium(VI) Electrophoresis Apparatus Injection technique Modeling

"Flow Injection Capillary Electrophoresis Coupling To Automate Online Sample Treatment For The Determination Of Inorganic Ions In Waters"
J. Chromatogr. A 1997 Volume 791, Issue 1-2 Pages 279-287
Lourdes Arce, Angel R&iacute;os and Miguel Valc&aacute;rcel*

Abstract: An automated interface for coupling flow injection (FI) systems with capillary electrophoresis (CE) has been developed and tested to combine the sample preparation capabilities of FI systems with the separation and determination provided by CE. To demonstrate the usefulness of such integration, two automated methodologies have been developed for on-line multiparametric monitoring of both anionic and cationic species in a water purification plant, to provide continuous control of the quality of the water. The concentration of anions such as chloride, nitrate, nitrite, sulphate and phosphate, of cations such as sodium, potassium, ammonium, calcium, magnesium, iron, and of heavy metals at trace level (e.g., manganese, aluminium, lead, cadmium), pre-concentrated in the flow system, is provided in an integral manner by the operational procedure proposed in this paper. The determination limits established by legislation in OECD countries have been achieved demonstrating the potential of CE to be applied to real samples.
Cations Electrophoresis Post-column derivatization Preconcentration Optimization

"A Microbioreactor Based On Interfacial Polymerisation And Application To Flow Injection Analysis Of Glucose"
Sens. Actuat. B 1996 Volume 34, Issue 1-3 Pages 422-428
Muntak Son, Frank Peddie*, Dennis Mulcahy, David Davey and Malcolm R. Haskard

Abstract: A bioreactor chamber was created by anisotropic etching of a Si wafer. The chamber was attached to a microelectronic sensor using epoxy resin. A biocatalyst, e.g., an enzyme, a combination of enzymes or intact viable cells, could then be contained within the chamber by an ultra-thin nylon membrane (preparation details given). The membrane was tightly sealed to the Si wafer surface by pretreating the wafer with a silylating reagent by dipping into dry toluene containing 10% γ-aminopropyl triethoxysilane and refluxing for 24 h. The membrane was then created by interfacial polymerization. The nylon membrane could then be covalently linked to the wafer surface by appropriate selection of aqueous and organic phase constituents. The microbioreactor was successfully used as a glucose sensor within a flow injection cell; results indicate that many other applications are feasible.
Glucose Sensor Nylon

"Solvent Extraction-spectrophotometric Determination Of Trace Orthophosphate In Water By Stopped-flow Time Difference Analysis Technique"
Anal. Sci. 1987 Volume 3, Issue 6 Pages 531-534

Abstract: Sample solution (500 mL), containing up to 2.5 g of PO43-, is treated with 10 mL of 0.35 M H2SO4 and extracted with 100 mL of isobutyl alcohol. To the aqueous layer is added 60 mL of 0.012 M (NH4)6Mo7O24. After thorough shaking, the solution is allowed to stand for 15 min and is then extracted with 20 mL of isobutyl alcohol. To a 5 mL fraction of the final organic phase is added 0.2 mL of 1 M HCl. For analysis, equal volumes of test solution and color-developing reagent (0.4 g of SnCl2.2H2O in 100 mL of isobutyl alcohol under N) are mixed in a stopped-flow spectrophotometer (Union Giken SF-70), and the absorbance is measured at 730 nm for ≈0.5 s as a function of time. The calibration graph of net change in absorbance is rectilinear up to 5 g l-1, with a detection limit of ≈0.3 g l-1. Interference is caused by As(III), As(V) and Si(IV). Recoveries of PO43- from tap-water were 93.6 to 105.9%; the coefficient of variation was <3% (n = 5).
Phosphate Spectrophotometry Sample preparation Stopped-flow Solvent extraction

"Determination Of Sub-nanomole Hydrogen Peroxide By Electrochemiluminescence Of Luminol In Aqueous Solution"
Anal. Sci. 1988 Volume 4, Issue 1 Pages 9-12

Abstract: Luminol (17 µM, in phosphate buffer solution of pH 7.4) was oxidized electrochemically at a Pt electrode, with an optimum applied potential of 0.7 V vs. SCE. Luminescence produced by further oxidation by H2O2 in the test solution was recorded at 436 nm; its half-life was 0.2 s. Flow injection analysis (flow rate 0.5 mL min-1) was carried out in an electrochemiluminescence cell at 0.7 V with the phosphate buffer as carrier containing 17 µM-luminol. The detection limit was 66 pmol of H2O2. A carrier solution at pH 9.2 containing 2% of acetonitrile gave a detection limit of 30 pmol, but background luminescence was increased.
Hydrogen peroxide Chemiluminescence Electrode Optimization

"Determination Of Ozone Decomposition Rate By Flow Injection Technique"
Anal. Sci. 1988 Volume 4, Issue 6 Pages 645-648
Y. Onari

Abstract: The flow injection analysis (FIA) of dissolved ozone was investigated by employing 2% potassium iodide-0.1% starch aqueous solution as a reagent. The sampling rate and the detection limit were improved compared with values obtained with potassium iodide aqueous solution as the reagent. The sampling frequency and the reproducibility of FIA signal were 105 samples h-1 and RSD=0.28% (2.12 mg L-1 O3; n=5), respectively. The S/N of FIA signal was good (0.24 mg L-1 O3; S/N, 7.0), and the sub mg L-1 levels of ozone were easily detected. The kinetic order of ozone decomposition in water was examined by using this FIA. Application to the determination of ozone decomposition rate was achieved.
Ozone Spectrophotometry Catalysis Kinetic

"Flow Injection Acid Hydrolysis Technique For Determination Of Organic Phosphates"
Anal. Sci. 1993 Volume 9, Issue 3 Pages 397-399

Abstract: Sample (0.5 µL) was injected into the water carrier stream (0.5 ml/min), merged with a 2 M H2SO4 stream (0.5 ml/min) and fed into the hydrolysis coil (30 m x 0.5 mm i.d.) at 170°C. The emerging solution was mixed with Mo reagent solution (0.5 ml/min) and passed into the coloration reaction coil (10 m x 0.5 mm i.d.) at 120°C. The solution was then cooled and the absorbance measured at 820 nm. Organic phosphates in the range 20-500 µM were determined. When 50 µM-O-phospho-DL-tyrosine was analyzed repeatedly the RSD (n = 20) was 2.6% with a sampling rate of 20 sample/h. The cited method was applied to organic phosphates such as phosphoamino-acids and nucleotides. The calibration graphs for phospho-L-arginine and D-ribose-5-phosphate were rectilinear for 20-500 µM-organic phosphates. The detection limits were ~50 pmol of organic phosphates. The present FIA system may be useful as a post-column reaction detector for HPLC analysis of organic phosphates.
Phosphate, organic Spectrophotometry

"Indirect Photometric Determination Of Potassium Ions With A Bulky Anion And A Crown Ether Using A Flow Injection Technique"
Anal. Sci. 1994 Volume 10, Issue 1 Pages 187-192

Abstract: The solubility products of alkali metal ions and bulky anions such as Hexyl (2,4,6,2',4',6'-hexanitrodiphenylaminate ion) and its analogues in the presence of crown ether were measured. The crown ether complexes were less soluble in water than the metal ions themselves when they formed such ion-association complexes. The precipitation reaction was used for the FIA-spectrophotometric determination of K+ in water. Sample (100 µL) was injected into a carrier stream of water and merged with a reagent stream containing 1 mM dicyclohexano-18-crown-6, 0.2 mM Hexyl lithium salt, 2 mM LiEDTA, 1 mM LiOH and 5 µM-KCl. Both streams were at a flow rate of 0.4 ml/min, the reaction coil (5 m x 0.5 mm i.d.) was maintained at 25°C and detection was at 490-520 nm using an 8 µL, 10 mm flow-through cell. The calibration graph was linear from 2 µM to 0.1 mM K+; the use of α-Hexyl reduced this to 0.1-10 µM. Interference by Ca and Mg ions was reduced by the inclusion of EDTA in the reagent solution; a large concentration of Na+ gave a positive error.
Potassium Spectrophotometry Interferences Crown ether Indirect

"Cobalt(III) Oxidation Of Organic-compounds And Its Application To A Determination Of Chemical Oxygen-demand At Room-temperature"
Anal. Sci. 1997 Volume 13, Issue 4 Pages 607-612

Abstract: Cobalt(III) oxidation of diverse organic compounds was studied in a batch system. An aqueous solution of an organic compound was mixed with a cobalt(III) solution (ca. 0.04 mol L-1), prepared through the electrolysis of a cobalt(II) solution in a strong acidic medium, with a volume ratio of 1:2. The oxidation of the organic compound was evaluated from the decrement in absorbance of the mixed solution at 610 nm, the wavelength of absorption maximum of the cobalt(III) ions. The cobalt(III) ions were found to be strong enough to oxidatively decompose organic compounds at room temperature; the oxidation was rapid and almost complete in 10 min. The chemical oxygen demand (COD) of sample solutions was calculated from the amount of cobalt(III) ions consumed for the oxidation. The obtained COD value for each sample was comparable to that determined by an official method based on permanganate oxidation. It is concluded that not only is the cobalt(III) oxidation practical for the treatment of organic compounds but it has possibilities as a novel method of COD determination, because it can be done rapidly in a simple operation with no requirement for heating. 29 References
Chemical oxygen demand Spectrophotometry Indirect Method comparison Standard method

"Low Cost Continuous-flow Analysis. Flow Injection Techniques In Atomic Absorption Spectrometry"
Anal. Proc. 1981 Volume 18, Issue 12 Pages 542-545
J. F. Tyson

Abstract: In this paper the combination of a flow injection sample introduction system with an atomic absorption spectrometer is described, in which low, medium and high dispersion of the sample in the carrier stream have been utilised. A simple model of the dispersion is proposed to account for the absorbance - time behavior observed and for the results of preliminary experiments, in which sample solution is continuously pumped.
Calcium Spectrophotometry Theory

"Luminescence Detection In Flow Injection Analysis"
Anal. Proc. 1981 Volume 18, Issue 6 Pages 264-266
J. N. Miller

Abstract: Many analyzes in biochemical and environmental sciences present formidable problems to the analyst: in addition to the requirements of extreme sensitivity and selectivity (arising from the small and/or dilute samples, and the complex sample matrices, respectively), satisfactory methods should be simple, readily automated and economical in their consumption of reagents. There may also be a requirement for portable apparatus, for example in field studies or bedside patient monitoring. In these circumstances the convenience and flexibility of flow injection analysisl-3 offer many advantages. Surprisingly, however, only a small proportion of the rapidly expanding literature on flow injection methods describes the application of photoluminescence and chemiluminescence detection methods (4-9). This paper reviews the work performed in the author's laboratory to develop procedures combining flow injection and luminescence methods.
Drugs Clinical analysis Luminescence Review

"Having Led This Horse To Water Can We Make It Think?"
Anal. Proc. 1993 Volume 30, Issue 3 Pages 143-144
Paul MacLaurin, Paul J. Worsfold, Philip Norman, Michael Crane

Abstract: A brief review of flow injection analysis is presented, with consideration of process applications, multi-determinations (preferably with multi-detection systems), multivariate calibration and the combination of flow injection with photodiode-array detection and principal component analysis. The last-named technique, with use of a simple two-line, single-injection manifold and measurement of the visible spectrum at the max. transient response, was tested for the simultaneous determination of Cl and orthophosphate in cooling water by means of the o-tolidine and molybdophosphoric acid reactions. Partial-least-squares regression modeling of the data with cross-validation produced a model in which two factors accounted for 99% of the concentration. variance. (27 references).
Chlorine Reverse Multidetection Photodiode Review Multivariate calibration Principal component analysis

"Online Liquid-liquid Extraction With Very Near-infrared Fluorescence Detection"
Anal. Proc. 1993 Volume 30, Issue 3 Pages 129-131
Ravinder K. Hindocha, James N. Miller, Nichola J. Seare

Abstract: An aqueous solution of Na dodecyl sulfate or polyoxyethylene dodecyl ether as the probe substance was injected into a stream of water. The resulting stream was merged with an aqueous solution (10 µg mL-1) of Rhodamine 800 dye, with passage through a mixing coil, before online extraction of the ion-pair complex formed into CHCl3. The mixture was passed through a phase separator to a fluorimetric detector operated at 700 nm (excitation at 690 nm). The response was rectilinear up to 0.1% or up to 0.006% of surfactant under either flowing or static conditions, respectively. The background value was high, and the use of a different extraction solvent might afford greater sensitivity.
Surfactants Fluorescence Sample preparation Ion pair extraction Phase separator

"Determination Of Ammonium Nitrogen In Water And Soil By Flow Injection Analysis"
Agrochemia 1991 Volume 31, Issue 4 Pages 87-90
Solich, P.;Cap.P.;Karlicek, R.

Abstract: NA
Ammonium, nitrogen

"Use Of Segmented Micro-continuous-flow Analysis And FIA In Water Analysis"
Am. Environ. Lab. 1989 Volume 1, Issue 2 Pages 60-63
Straka, M.R.

Abstract: The complementary nature of the methodologies of macrosegmented and microsegmented continuous-flow and nonsegmented FIA is discussed. The relative advantages and disadvantages are highlighted and general guidelines for selection of one technique over another are suggested.
Method comparison Alpkem Review Apparatus

"Direct Injection Enthalpimetry: Static Methods"
Am. Lab. 1981 Volume 13, Issue 1 Pages 63-72
Rogers, D.W.

Abstract: A review with 41 references. (SFS)
Enthalpimetry Theory

"USEPA Regulation Of FIA Methods For NPDES And NIPDWR Monitoring Of Waters And Wastes"
Am. Lab. 1988 Volume 20, Issue 9 Pages 42-49
Ranger, C.B.

Abstract: A review with no references on EPA-approved flow injection analysis methods for the analysis of water and wastewater in compliance with the National Pollution Discharge Elimination System and the National Interim Primary Drinking Water Regulations.
Water Review Standard method

"Online Kinetic Measurement Of Water Toxicity Using The Photobacterium Vibrio Fischeri"
Anal. Commun. 1996 Volume 33, Issue 9 Pages 335-338
Peter R. Fielden, Tom McCreedy, Richard D. Snook and Bernard J. Treves Brown

Abstract: A new approach to toxicity measurements is described; the quenching of luminescent bacterium Vibrio fischeri is used with an online PC-controlled flow analysis system (schematic given). Two toxic compounds were determined: 3,5-dichlorophenol and formaldehyde. Bacteria samples were reconstituted using microtox medium (Microbics) and challenged with different concentrations of each of the toxic substances in the ppm range. The PC-controlled FIA system cycled through four stages: flush (samples are mixed with saline); mixing (photobacterial reagent was added); read (photomultiplier detection); then the system was flushed with saline and the rate of light decay was calculated using a PC (theory given). The entire system was maintained at 15°C. Calibration graphs of light decay vs. time gave an indication of relative toxicity.
Kinetic Quenching

"Rapid, Automated Analysis Of Carbon-13 And Oxygen-18 Of Carbon Dioxide In Gas Samples By Continuous-flow, Isotope Ratio Mass Spectrometry"
Biol. Mass Spectrom. 1991 Volume 20, Issue 11 Pages 724-730
S. J. Prosser, S. T. Brookes, A. Linton, T. Preston

Abstract: An automated continuous-flow system is described (diagram given). Breath is collected in either Vacutainers or Exetainers placed in an autosampler. The sample gas is flushed out of the container into a He flow which is passed through a drying tube containing MgClO4 and then to a GC column (18 in x 0.25 in) of Carbosieve-G operated at 60°C to 120°C. The carrier gas containing the separated CO2 is passed to the ion source of a mass spectrometer. The system is evaluated by determining isotope ratios of 13C:12C in breath CO2, 18O:16O in water, 18O:16O in breath CO2 contaminated with N2O.
Carbon-12 Carbon-13 Oxygen-16 Oxygen-18 GC Mass spectrometry Automation Carrier gas Heated reaction Isotope ratio

"Flow Injection Immunoanalysis (FIIA)--a New Immunoassay Format For The Determination Of Pesticides In Water"
Biosens. Bioelectron. 1991 Volume 6, Issue 3 Pages 239-243
Petra Kr&auml;mer and Rolf Schmid

Abstract: This paper presents the development of a new heterogeneous enzyme immunoassay format for the detection of pesticides. It uses the technique of a flow injection system and is named flow injection immunoanalysis (FIIA). Results are demonstrated for the measurements of the herbicide atrazine, which belongs to the triazines, and the potential of this method compared with another immunoassay format (ELISA) is discussed. A solution of pesticide (e.g., atrazine) is passed across an immunoaffinity membrane (PALL Immunodyne) containing immobilized antibodies (prep. described) at 0.78 mL min-1 for 3 min. After rinsing with 80 mM phosphate buffer (pH 7.3), five 40 µL portions of peroxidase-labelled atrazine are passed over the membrane in a series of stop - start cycles of 20 s duration. After further rinsing with buffer solution, 40 µL of 5 mM hydroxyphenylpropionic acid and 40 µL of 2 mM H2O2 are injected into the carrier buffer solution, and when the reagents reach the membrane reactor the flow is stopped. After 2 min the flow is re-started and the fluorescence of the enzyme-generated product is measured at 404 nm (excitation at 320 nm) in a flow-through fluorimeter. The analytical range is 0.02 to 0.3 µg L-1 of atrazine. The coefficient of variation of the proposed method were greater over the whole range than those of the ELISA method of Wittmann and Hock (Food Agric. Immunol., 1989, 1, 211), and the reasons for this are explained. The polyclonal antiserum used in the assay exhibited significant cross-reactivity with propazine and simazine.
Pesticides Fluorescence Immunoassay Sensor Buffer Enzyme Membrane Stopped-flow

"Application Of Flow Injection Analysis To Water Quality Monitoring System"
Boshoku Gijutsu 1987 Volume 36, Issue 4 Pages 234-238
Yasuo Kondo, Hiroaki Shimomura, Michio Katoh

Abstract: For an open cooling water system with a zinc-polyphosphate inhibitor, a water quality monitoring system adopted Flow Injection Analysis was introduced. Concentrations of phosphate (inhibitor) and Fe(II) ions were measured automatically by the analytical flow system. Analytical curves for phosphat and Fe(II) ions have good linearity, and their correlation coefficients were 0.9995 and 0.9999, respectively. Reproducibility of measured value for Fe(II) ions was very good and that for phosphate ions was not so good. But these results were satisfactory for practical purposes. When the analytical flow system was applied to on-line monitoring, measured value for phosphate ions have a little amount of scatter. The reason may be explained as follows: 1) the conversion rate of phosphorus forms, during water sample is running through the heated zone, has slightly different at each measurment, and 2) the capability of ascorbic acid as a reducing agent for antimony-phospho-molybdate complex becomes weak with lapse of time. However, this water quality monitoring system has been developed to the point of being usable in practical applications.
Iron(2+) Phosphate Process control

"The Oxidation Behavior Of Various Organic Compounds In The Determination Of Chemical Oxygen Demand By Means Of Flow Injection Analysis With Acidic Permanganate"
Bull. Chem. Soc. Jpn. 1982 Volume 55, Issue 8 Pages 2622-2627
Takashi Korenaga,Hisayoshi Ikatsu and Tosio Moriwake

Abstract: Forty-five organic compounds have been oxidized with an acidic permanganate solution under various oxidation conditions. In an attempt to determine the standard substance for chemical oxygen demand (COD), their oxidation behavior is analyzed in detail with respect to the reaction temperature and the reaction time by means of flow-injection analysis using ammonium iron(I1) sulfate as the internal standard. The compounds used are classified into three groups according to the oxidation values obtained by the standard CODMn method. The results show that the compounds with oxidation values of more than 50% are easily oxidized with acidic permanganate, even under relatively mild conditions; those with oxidation values of 5-50% are severely influenced by the reaction temperature and the reaction time, and those with oxidation values of less than 5% are seldom oxidized at below 100°C or for less than 30 min. As a standard substance for COD, it has been established that a mixture of the compounds has to be properly chosen from the aforementioned three groups according to the oxidation behavior of the water sample. The addition of silver nitrate to the oxidation system accelerates the oxidation reaction with acidic permanganate, whereas that of phosphoric acid suppresses the oxidation of organic compounds.
Chemical oxygen demand Spectrophotometry Heated reaction Interferences Optimization

"Application Of The Flow Injection Analysis Based On Iodometry To The Determination Of Ozone Decomposition Rate"
Bull. Chem. Soc. Jpn. 1987 Volume 60, Issue 8 Pages 3074-3076
Yasuo Onari

Abstract: The determination of ozone decomposition rate by flow injection analysis (FIA) was investigated. Under the conditions studied a sampling rate was about 43 samples/h, and the pseudo-first-order kinetic plot of the obtained data showed a good linearity. This FIA method seems to be useful for kinetic measurement of ozone decomposition in water.
Ozone Spectrophotometry Kinetic

"Apparatus For Measuring Chemical Oxygen Demand Based On Flow Injection Analysis"
Bunseki Kagaku 1980 Volume 29, Issue 3 Pages 222-223

Abstract: A simple apparatus was developed for the rapid and continuous determination of chemical oxygen demand (COD) in environmental water samples based on the principle of flow injection-spectrophotometric analysis. A solution of 2.7 x 10^-4 M potassium permanganate in 3.3% sulfuric acid was pumped with a reciprocating pump into the manifold to which 20µl of sample (i.e. sodium oxalate solution) was also introduced by manual injection. After reaction, the mixture went through a quartz flow cell (10 mm light path, 18 µL volume) placed in a spectrophotometer operated at a wavelength of 525 nm. The manifold was made entirely of polytetrafluoroethylene tubing (0.5 mm inner diameter, 10 m length). The signal from the spectrophotometer was continuously recorded. When a pumping rate was chosen to be 1.9 mL min^-1 a residence time was 1 min. A sampling rate of 120 samples per hour was achieved and the apparent COD at a concentration range of 21-170 mg COD L^-1 was measured reproducibly. Chloride at 10 mg L-l level was suppressed by adding 0.1% silver nitrate in the flow injection system.
Chemical oxygen demand Spectrophotometry Apparatus

"A Flow-coulometric Method For The Rapid Determination Of Orthophosphate Ion"
Bunseki Kagaku 1980 Volume 29, Issue 6 Pages 367-372
FUJINAGA Taitiro OKAZAKI Satoshi HORI Toshitaka

Abstract: A flow-coulometric method at the column electrode has been developed for the determination of orthophosphate ion. The principle of the method was as follows: into a steady flow of carrier solution composed of 0.05 M Na2MoO4, 1.2 N H2SO4, and 20 % ethanol, was injected an aliquot of 10^-100 µL of phosphate sample. The phosphomolybdate complex formed instantaneously (within 20 s) in the flow line was led to the column electrode kept at +0.25 V vs. Ag-AgCl. The electrolytic reduction proceeded with two-electrons per molecule. The reduction current of the complex was recorded automatically and the amount of phosphate was determined from the net electricity consumed for the electrolysis. When an aliquot of 100 µL of sample injected at each run to the carrier stream controlled at a rate of 5 mL/min, the sample containing phosphate ranging from 1 x l0^-5 M to 1 x 10^-3 M can be analyzed within 2 min.
Phosphate Phosphates Coulometry Complexation

"Catalytic Determination Of Trace Amounts Of Manganese With A Flow Injection System"
Bunseki Kagaku 1984 Volume 33, Issue 12 Pages 652-656
Yamane, T.;Nozawa, Y.

Abstract: A 75 µL portion of the sample solution is injected into a carrier stream of water, which then meets mixed streams of 0.052 M 3,4-dihydroxybenzoic acid(I), aqueous 1.5% H2O2 and 1 M Na2CO3. All four streams are pumped at 0.48 mL min-1. The Mn-catalyzed oxidation of I takes place in a reaction coil (5 m x 0.5 mm), and the absorbance is monitored at 480 nm. The calibration graph (peak heights) is rectilinear up to 40 ng mL-1 of Mn, and the limit of detection is 1 ng mL-1. About 60 determinations can be carried out in 1 h. The coefficient of variation (n = 15) for 10 ng mL-1 of Mn was 2.0%. There is serious catalytic interference from Co, and Fe(III) and Cr(III) also interfere in twenty- and ten-fold excess, respectively.
Manganese Spectrophotometry Catalysis Interferences

"Flow Injection Determination Of Fluoride Ions Using Catalytic Reactions"
Bunseki Kagaku 1985 Volume 34, Issue 1 Pages 31-35
Toda, K.;Sanemasa, I.;Deguchi, T.

Abstract: After being allowed to stand overnight, 0.1 mM xylenol orange(I) in 0.6 M HCl or 0.1 mM methylthymol blue(II) in 0.5 M HCl and 0.2 mM ZrCl4 in 0.06 M HCl were mixed. The sample solution (235 µL) was injected into the carrier stream of water (2.0 mL min-1) which then flowed into the reagent stream (0.5 mL min-1). After passing the solution through a 3-m reaction tube, the absorbance was measured at 550 or 586 nm for the I or II complex, respectively. The detection limit was 0.01 ppm. Aluminum, Cu(II), Fe(III), SO42-, SO32-, silicate and organic acids interfered.
Fluoride Spectrophotometry Catalysis Interferences General

"Determination Of Total Nitrogen In Waters By A Continuous-flow Method Involving Alkaline Peroxodisulfate Digestion"
Bunseki Kagaku 1986 Volume 35, Issue 1 Pages 32-37
Aoki, T.;Uemura, S.;Munemori, M.

Abstract: Water (at 2 mL min-1) is continuously mixed with 0.1 M K2S2O8 (6 M in NaOH and plus 0.1% of Se), at a flow rate of 1.5 mL min-1, and the mixture is heated in a reaction coil (80 cm x 1.5 mm) at 175°C. After cooling in an ice bath, the reaction mixture is passed to a debubbler and mixed with 4% TiCl3 solution (0.7 mL min-1), thereby reducing NO3- to NH3, which is passed to a double-tube separation unit. The NH3 in the outer tube passes through a micro-porous PTFE membrane into the inner tube, through which phthalaldehyde reagent is passed (0.3 mL min-1), and the fluorescence of the emergent solution is measured at 486 nm (excitation at 370 nm). The response (obtained in <10 min) is rectilinearly related to concentration. of N from 0.02 to 10 mg l-1, the detection limit is 9 µg l-1, and the coefficient of variation at the 0.2 mg L-1 level is 2.5% (n = 4). There is no interference from coexisting inorganic salts.
Nitrogen, total Fluorescence Sample preparation Gas diffusion Heated reaction Interferences Microporous membrane Online digestion Teflon membrane Debubbler

"Online Concentration And Flow Analysis Of Trace Amounts Of Bismuth With Anion-exchange Method And Ion-exchanger Absorptiometry"
Bunseki Kagaku 1987 Volume 36, Issue 11 Pages 656-661
Yoshimura, K.

Abstract: Bismuth (0.012 to 0.5 nmol) in various samples (e.g., 1 l of water) was pre-concentrated as a chloro-complex from 0.1 to 0.6 M Cl- by using a Dowex 1-X8 anion-exchange column (Cl- form; 100 to 200 mesh). Bismuth was desorbed with 0.15 M H2SO4 at a flow rate of 1.2 mL min-1 and mixed with a solution containing 1 M KI at 0.3 mL min-1. After introduction into the flow-through cell, the light path portion of which was filled with QAE Sephadex A-25 anion exchanger, the light attenuation due to the iodo-complexes of Bi (concentrated on the anion exchanger in the cell) was measured directly at 472 nm, with high precision. The calibration graph for Bi was rectilinear and the method was applied to samples of rocks and metals.
Bismuth Ion exchange Spectrophotometry Preconcentration Dowex Resin Sephadex Solid phase detection

"Application Of Flow Injection Analysis Method To Water Quality Analysis"
Bunseki 1987 Volume 36, Issue 4 Pages 245-252
Korenaga, T.

Abstract: A review is presented, covering the period from 1982 to 1986. The dissolved components, e.g., metal ions, N compounds, P compounds and anions, determined by flow injection are tabulated. (156 references).
Ammonia Metals Nitrate Nitrite Phosphate Review Silica

"Determination Of Boron By Spectrophotometric FIA Using Azomethine H"
Bunseki Kagaku 1993 Volume 42, Issue 6 Pages 351-355
Nose, K.;Zenki, M.;Shimoishi, Y.

Abstract: A sample solution containing 1 ppm B was injected into a carrier stream of water and mixed with a reagent stream of 0.25% azomethine H, 1% asorbic acid, 1% EDTA and 0.8 M (NH4)2HPO4 buffer (pH 7.2) in a reaction tube (10 m x 0.5 mm) at 0.9 mL min-1. Absorbance was measured at 425 nm. The calibration curve was rectilinear from 0.1 to 1 ppm B with coefficient of variation (n = 15) of 0.6% and 0.2% for 0.2 and 0.8 ppm B, respectively. The method was used for the determination of B in eye lotions.
Boron Spectrophotometry EDTA

"Determination Of Ammonia/ammonium Ion In Water By Continuous-flow Chemiluminescence After Derivatization To An Isoindole"
Bunseki Kagaku 1993 Volume 42, Issue 10 Pages 625-629
Takeuchi, K.;Fushimi, C.;Nakamura, K.;Ibusuki, T.

Abstract: A continuous-flow chemiluminescence system for the cited determination is described; flow diagram given. Online derivatization of NH3 was carried out with OPA reagent (10 mM o-phthaldialdehyde/15 mM 2-mercaptoethanol/10 mM phosphate buffer of pH 10.5). A 0.5 mM bis-(2,4,6-trichlorophenyl)oxalate (TCPO) acetonic solution and 0.5% H2O2 were used as an oxalate chemiluminescence system. The flow rates of the sample, OPA reagent, TCPO and H2O2 solution were 0.48, 0.24, 2.1 and 0.24 ml/min, respectively. The calibration graph was rectilinear from 2.9 ng/ml (detection limit) to 6 µg/ml of NH3. Primary amines were derivatized and detected in addition to NH3, but the chemical species usually found in rainwater samples did not interfere with the assay.
Ammonia Ammonium Chemiluminescence Interferences

"Determination Of Arsenic And Selenium By Hydride Generation Atomic Absorption Spectrometry (flow Injection Or Continuous-flow) Method Combined With A Hydride Collecting Trap"
Can. J. Anal. Sci. Spectrosc. 1995 Volume 40, Issue 5 Pages 117-124
Siska, R.;Borszeki, J.;Gegus, E.

Abstract: A hydride collecting cold trap hydride generation AAS method has been developed using a flow injection (FI) or a continuous-flow (CF) system, applicable to the high sensitivity determination of arsenic and selenium, characterized by a detection limit of 10^-20 pg/mL. The best relative detection limits and sensitivity for this system could be achieved using the CF operation mode. Accuracy and reproducibility of the method were investigated by the analysis of dilute solutions produced by decomposition of international CRM samples of various types. The results of the determinations agree well with the certified values. Reproducibility of the measurements is good considering especially the extreme low initial concentrations. The remarkable feature of the method is the relatively low blank value which is partly due to the use of high purity acids and reagents, and partly to the very low risk of contamination when the work is done in a closed system. Further on, several water samples were investigated by this method, the arsenic and selenium content of which could not be determined previously. Also numerous food samples having low content of As and Se were analyzed. (12 references)
Arsenic Selenium Spectrophotometry Cold trap Optimization Reference material Volatile generation Volatile generation

"Spectrophotometric Determination Of Phenols By Flow Injection Analysis"
Chem. Anal. 1991 Volume 36, Issue 5-6 Pages 869-877
Kojlo, A.;Wolyniec, E.;Puzanowska Tarasiewicz, H.;Poltorak, J.;Grudniewska, A.

Abstract: Two procedures were carried out for the determination of phenols in water by flow injection analysis with spectrophotometric detection: (i), sample solution was reacted with 0.3% 4-aminoantipyrine solution in the presence of 0.9% K3Fe(CN)6 solution and borate buffer solution of pH 9.5, the flow-rate through out was 1.3 mL min-1 and detection was at 510 nm. (ii), A stream of 0.02 M NaNO2 was mixed with a stream of 1 mM p-nitroaniline in a reaction coil, the mixture was cooled to 0 ±3°C, and mixed with a portion (200 µL) of phenol solution and borate buffer solution of pH 9.5, the flow-rate through out was 1.8 mL min-1 and detection was at 475 nm. The detection limits were 0.06 and 0.03 ppm of phenol for methods i and ii, respectively. The results obtained for both methods compared well with one another. The influence of interfering compounds for both methods is graphically presented. The results of the determination of phenols in 20 samples of running water are tabulated.
Phenols Spectrophotometry Buffer Interferences

"Flow Injection Analysis Of Aqueous Ozone Based On The Ozone Decoloration Reaction Of 1-(2-hydroxy-5-sulfophenylazo)-2-napthol"
Chem. Express 1989 Volume 4, Issue 6 Pages 369-372
Onari, Y.

Abstract: The determination of ozone (O3) in water based on the decoloration reaction of 1-(2-hydroxy-5-sulfophenylazo)-2-naphthol was examined by using flow injection analysis (FIA) technique. The precision of FIA signal was good and the rapid determination (120 samples/h) of sub mg/L - mg/L levels of aqueous O3 were obtained. (SFS)
Ozone Spectrophotometry Indirect

"Selective Determination Of Iodide And Iodate In Brine Waters By Atmospheric Pressure Helium Microwave-induced Plasma Atomic-emission Spectrometry With Continuous-flow Generation Of Volatile Iodine"
Chem. Express 1991 Volume 6, Issue 1 Pages 5-8
Nakahara, T.;Yamada, S.;Wasa, T.

Abstract: A method is described for the determination of iodide and iodate in brine by atmospheric pressure helium microwave-induced plasma AES. The method is based on the continuous evolution of volatile iodine by oxidation of iodide with sodium nitrate. Differentiation of iodide and iodate is achieved by pre-reduction of iodate to iodide with ascorbic acid. The detection limit is 2.3 ng mL-1 of iodine. Recoveries of added iodine were 94.2 to 103. 5%.
Iodate Iodide Spectrophotometry Selectivity

"Comparison Of Methods In Analytical Practice. 2. Determination Of Ammonium In Water"
Chem. Labor Betr. 1997 Volume 48, Issue 1 Pages 12-14
Schwedt, G.;Laue, D.

Abstract: A comparison is made between spectrophotometry based on the indophenol reaction, direct potentiometry with a polymer-based ion-selective electrode, and FIA with diffusion of NH3 into a mixed indicator for the determination of NH4+. Apparatus and procedures used, limits of detection and determination, linear ranges, analysis times and other performance criteria are tabulated. Spectrophotometry is the most sensitive method, potentiometry has the widest range of measurement, and FIA is the most suitable for automation.
Ammonium Spectrophotometry Potentiometry Electrode Automation Method comparison Gas diffusion

"Flow Injection Analysis Of Inorganic Ortho- And Polyphosphates Using Ascorbic Acid As A Reductant Of Molybdophosphate"
Chem. Lett. 1980 Volume 9, Issue 5 Pages 499-502
Yukio Hirai, Norimasa Yoza and Shigeru Ohashi

Abstract: A spectrophotometric method based on the formation of heteropoly blue complex was applied to the flow injection analysis of inorganic ortho-and polyphosphates such as diphosphate and triphosphate. Ascorbic acid was used to reduce molybdophosphate. Total amounts of inorganic ortho-and polyphosphates could be determined at a sampling rate of 45 samples/h with a relative standard deviation of less than 1%.
Phosphate Polyphosphates Spectrophotometry Heated reaction

"Direct Potentiometric Measure Of The Fluoride, Chloride, Cyanide, Sulfide, Nitrate, And Ammonium Ions In Waters And Waste Waters"
Chem. Tech. 1975 Volume 4, Issue 5 Pages 183-188
Oehme, Friedrich

Abstract: Photometric and direct potentiometric methods for the determination of the more important ions present in waters and effluents are compared, and the fundamentals and possibilities of potentiometric ion measurements are reviewed. The construction, suitablity, stability, reproducibility, and selectivity of ion-sensitive electrodes used in continuous measuring application are discussed. 28 references (SFS)
Fluoride Chloride Cyanide Sulfide Nitrate Ammonium Potentiometry Apparatus Detector

"Spectroscopic Analysis Of Electrochemical Processes By Using A Column-electrolysis Method"
Denki Kagaku 1993 Volume 61, Issue 1 Pages 100-101
Oyama, M.

Abstract: A review, with 8 refs., is given on the title subject, describing a pulse-electrolysis stopped-flow method with the anal. of rate processes of fast chemical reactions, and a resonance Raman scattering method with some examples. Future prospects of the application of these methods are also described. (SFS)
Electrochemical analysis Raman Stopped-flow

"The Flow Injection Analysis Technique. A Fast Method For The Determination Of Nitrogen In Water"
Eau Ind. Nuisances 1985 Volume 90, Issue 1 Pages 53-55
Robert, P.;Boulet, P.;Lerique, M.D.

Abstract: A flow injection analysis (FIA) application, i.e., the FIAstar Tectator, for rapid N determination in water comprises a central unit having an injection system, a chemifold, and reagent flasks; a detector with a printer, and a sample feed unit. Results can be obtained in 30 s with low consumption of reagents (0.3 - 1 mL/min), rapid passage from one sample to the next, and little maintenance of the app. N determination is based on the reaction of aqueous NH4+ with NaOH to produce NH3 gas and a color change in an indicator that can be measured photometrically. The determination of nitrites is based on the sulfanilamide-naphthyl-ethylene diamine reaction and colorimetric analysis at 540 nm. Nitrates can be determined by adding a Cd column that permits the reduction of nitrates to nitrites. Several different types of detectors can be coupled to the app. (fluorimeters, photometers, spectrophotometers, etc.) and the unit itself can be used in other applications: measurement of alkynes, phosphates, Si, Al etc.
Ammonia Nitrogen Spectrophotometry Tecator

"AAS Determination Of Trace Lead In Waters And Human Hair With Online Flow Injection Coprecipitation With Zinc Diethyldithiocarbamate As Carrier"
Fenxi Ceshi Xuebao 1997 Volume 16, Issue 1 Pages 25-29
Jin Jingchao, Chen Hengwu

Abstract: Hair (0.5 g) was digested with 10 mL of HNO3 and 1 mL of HClO4 by heating on a sand bath to near-dryness. The digest was dissolved in 4 mL of 6 M HCl with heating, and the solution was mixed with 5 mL each of 0.15% Zn(II) solution and 10% ascorbic acid and diluted to 50 mL with water. The solution was then submitted to online pre-concentration by diethyldithiocarbamate coprecipitation and flow injection GFAAS (flow diagram and procedure given). The detection limit was 2.7 ng/ml of Pd, and the RSD (n=11) was 1.3% at 200 ng/ml. The method was also used to determine Pb in water, with recoveries of 97-106%.
Lead Sample preparation Spectrophotometry Preconcentration Coprecipitation

"Determination Of Trace Thorium In Water By Flow Injection Fluorescence Spectrophotometry With Micro-column Online Preconcentration"
Fenxi Huaxue 1991 Volume 19, Issue 9 Pages 1075-1077
Shen, Z.;Zhang, Y.;Guo, D.;Huang, Y.

Abstract: An online pre-concentration time-resolved flow injection fluorimetric method was developed for the determination of Th in water based on measurement of the fluorescence intensity of the Th - morin - TOPO - sodium lauryl sulfate complex in 0.2 M H2SO4. The calibration graph was rectilinear for 80 ng of Th; the detection limit was 2.5 ng l-1. The coefficient of variation (n = 11) for 50 ng of Th was 3.6%. Sample throughput was 30 h-1.
Thorium-232 Fluorescence Column Preconcentration

"Novel Flow Injection Chemiluminescence Method For The Determination Of Nickel In Water Samples"
Fenxi Huaxue 1993 Volume 21, Issue 9 Pages 1052-1054
Li, H.;Yu, Z.A.

Abstract: Water (60 µL) was injected into the flow injection analyzer. (diagram shown) and carried by water (59 ml/min) to mix with a stream of 0.4 mM anthracene green (4.9 ml/min) prior to mixing with 2 M H2O2 (5.3 ml/min) in a PTFE reaction tube (14 cm x 0.8 mm) and 2 M KOH in a carrier stream of water (6.2 ml/min). Chemiluminescence intensity was measured. The calibration graph was linear for 5-300 ng/ml of Ni with detection limit of 0.11 ng/ml. After masking with sodium thiosulfate, 25-fold Co2+ did not interfere with the analysis.
Nickel Chemiluminescence Interferences

"Flow Injection Stopped-flow Catalytic-spectrophotometric Determination Of Trace Nitrite"
Fenxi Huaxue 1993 Volume 21, Issue 10 Pages 1237-1237
Yang, S.R.;Jie, Y.W.;Chen, H.Y.

Abstract: Water was treated with 0.2 M H2SO4 and diluted with water. Sample solution, 20 µM-Janus green and 6 mM KBrO3 (all containing 32 mM H2SO4) were fed at 1.7 ml/min into a reaction tube of an automatic flow injection analyzer. for 30-60 s, at 50°C for 90 s. The absorbance of the products was measured at 630 nm vs. water. Beer's law was obeyed up to 50 ng/ml of nitrate and the detection limit was 0.2 ng/ml. Recoveries ranged from 94-103%. The RSD was 3.7%.
Nitrite Spectrophotometry Stopped-flow

"Flow Injection Spectrophotometric Determination Of Sulfate In Water With Dimethylsulfonazo-III"
Fenxi Huaxue 1998 Volume 26, Issue 2 Pages 207-210
Sun, A.;Liu, D.;Guo, W.

Abstract: A new flow injection method for determination of sulfate in water is developed, based on the decoloration reaction between sulfate and Ba2+-dimethylsulfonazo-III complexes. A cation-exchange column which was used for removing of interference ions and a sample loop are mounted on the multifunction injection valve. The calibration graph of the proposed method is linear over the range 0-26 mg/L for sulfate. The ion-exchange column can be regenerated simultaneously during sample injection, the proposed method may be used for automatic monitoring of sulfate in water system.
Sulfate Ion exchange Spectrophotometry Interferences Indirect Injector Valve

"Determination Of Trace Anionic Surfactants Using Online Solvent Extraction-flow Injection Fluorimetry"
Fenxi Huaxue 1998 Volume 26, Issue 5 Pages 568-570
Gao, J.;Zhang, Z.;Zhu, Z.

Abstract: A method for determining trace amounts of anionic surfactants using online solvent extraction-flow injection fluorimetry has been developed. The linear range of determination is 0.01-0.20 mg/L. The sampling rate was 20 sample/h. The method has been used to determine trace anionic surfactants in water samples with satisfactory results.
Surfactants, anionic Fluorescence Solvent extraction

"Flow Injection Online Preconcentration With Anion Exchange Resin And Flame Atomic Absorption Spectrometric Determination Of Trace Copper"
Fenxi Huaxue 1998 Volume 26, Issue 11 Pages 1369-1371
Liu, J.;Chen, H.W.;Mao, X.

Abstract: A novel flow injection online µcolumn pre-concentration system with anion exchange-resin as sorbent was developed for flame atomic absorption spectrometric (FAAS) determination of trace copper in water. Under the optimized conditions, an enrichment factor of 23 was achieved for a loading period of 150 s. A detection limit (3s) of 0.2 µg/L and a relative standard deviation of 1.6% for 11 measurements of 40 µg/L copper standard solution were obtained at the sampling frequency of 20/h. Most ions existing in fresh water samples did not interfere with the copper determination The proposed method has been successfully applied to determine the trace amt. of copper in water samples.
Copper Spectrophotometry Ion exchange Preconcentration Resin Interferences Optimization

"Determination Of Copper In Water Samples By Flow Injection Solvent Extraction - Inductively Coupled Plasma Atomic-emission Spectrometry"
Fenxi Shiyanshi 1991 Volume 10, Issue 3 Pages 7-10
Wang Xiaoru and R. M. Barnes

Abstract: Sample is injected into the analyzer. (at 2.2 mL min-1) and is transferred to a 1.5-m extraction coil for extraction with 0.02% dithizone in CCl4 (at 0.03 mL min-1) for 80 s, before analysis of the organic extract by ICP-AES at 324.7 nm with use of an ultrasonic nebulizer. For 100 ng mL-1 of Cu, the coefficient of variation (n = 6) was 2.5% and the detection limit was 0.1 ng mL-1. A pre-concentration of ~100-fold can be achieved. Sampling rate was 25 h-1. The method was applied to NBS water standards and results compared well with certified values.
Copper Spectrophotometry Sample preparation Nebulizer Preconcentration Solvent extraction Reference material Dithizone

"Microamount Flame Atomic Absorption Technique And Its Application"
Fenxi Shiyanshi 1993 Volume 12, Issue 1 Pages 77-81
Gao, Y.Q.;Wu, R.;Chi, K.;Wu, H.Z.

Abstract: A theoretical model of the cited technique was developed (equations given) in order to improve sensitivity. Three examples are discussed: (i) trace Au in ores was determined using a combination of a high efficiency nebulizer (HEN), a high performance hollow cathode lamp (HPHCL), a slotted quartz tube (SQT) and FIA with a detection limit of 0.2 ng mL-1 of Au; (ii) trace Pb in water was determined using a combination of HEN, HPHCL and SQT with a detection limit of 1.6 ng mL-1 of Pb; and (iii) trace As in water was determined using a combination of HPHCL, SQT and a HG-3 hydride generator with a detection limit of 3 ng mL-1 of As.
Arsenic Spectrophotometry Spectrophotometry Theory

"Research On Ion-exchanger Phase Absorptiometry Combined With Flow Injection Analysis - Determination Of Trace Amounts Of Bismuth In Water"
Fenxi Shiyanshi 1993 Volume 12, Issue 4 Pages 26-28
Zhao, Z.Y.

Abstract: The apparatus used for the cited determination is illustrated and a type 721 spectrophotometer is fitted with a flow-through cell (8 x 3 mm i.d.), packed with 717 anion-exchange resin (65 mesh). Water was mixed with KI-saturated solution, the mixed solution was introduced into the carrier stream [0.25% KI solution containing 4.5% H2SO4 (w/v) and 1 mM Na2S2O3] and the attenuation of incident light of BiI3 on resin in the cell was continuously monitored at 490 nm. The Bi(III) content was determined by accumulation or stop-sampling methods. Results agreed with those obtained by AAS.
Bismuth Ion exchange Spectrophotometry Apparatus Method comparison Solid phase detection

"Study On The Determination Of Vanadium By Flow Injection Chemiluminescence Based On Coupled Reaction"
Fenxi Shiyanshi 1998 Volume 17, Issue 1 Pages 41-44
Li Weihua,Wang Zhanling,Li Jianzhong and Zhang Zhujun*

Abstract: A new method for determining V(IV) by flow injection chemiluminescence was developed. It is based on the oxidation of I- by K2Cr2O7 induced by V(IV), and the subsequent chemiluminescence reaction of luminol oxidized by I2. The CL intensity is linear to V (IV) concentration. over the range of 1 x 10^-5 ~ 1 x 10^-9 mol/L. The detection limit is 7 x 10^-10 g/mL, the relative standard deviation is 2.8% for 11 measurements of 8 x 10^-9 g/mL V(IV) standard solution The method was used to determine V in hair and water samples with satisfactory results.
Vanadium(IV) Chemiluminescence Indirect

"Approach For Improving The Linear Range In Flow Injection Analysis"
Fenxi Shiyanshi 1998 Volume 17, Issue 1 Pages 76-78
Wu, G.;Wu, N.

Abstract: It has been verified that in flow injection analysis with spectrophotometric detection and constant injected sample volume, the following expression is valid: c=a+b ln(1-h/h0), where c is the sample concentration, a and b are coefficients depending on experimental conditions, and h is the sample peak height, h0 is the steady state height which is almost unchanged with increasing sample concentration. Using this expression, the applicable concentration. linearity range can be enlarged, and the sample with higher concentration. can be analyzed.
Chloride Spectrophotometry Linear dynamic range

"Determination Of Aluminum In Water And Soils"
FIAstar Newsletter 1985 Volume 2, Issue 1 Pages 2-NA
Moller, J.

Abstract: NA
Aluminum Spectrophotometry Tecator

"Determination Of Water Soluble Surfactants By Liquid/liquid Extraction Based On Flow Injection Analysis"
FIAstar Newsletter 1986 Volume 4, Issue 1 Pages 1-NA
Sahlestrom, Y.

Abstract: NA
Surfactants Spectrophotometry Sample preparation Extraction Tecator

"A Continuous-flow System For Measuring In-vitro Oxygen And Nitrogen-metabolism In Separated Stream Communities"
Freshw. Biol. 1991 Volume 26, Issue 3 Pages 495-506

Abstract: 1. This paper describes a continuous-flow system that we have used extensively for measurement of oxygen exchange and nitrogen transformations in different communities of lowland streams, i.e. the water, the sediment, and the macrophyte-biofilm community. The system, which is set up on the stream bank, consists of several macrophyte and sediment chambers equipped with a double-flow system that ensures an internal water velocity close to that in the stream and which, by continuously renewing the water, mimics diel fluctuation in stream temperature and water chemistry. Water temperature and dissolved oxygen are measured continuously and the data stored on magnetic tape. Water samples are collected in a refrigerator and analyzed using standard chemical procedures. 2. The application of the system is illustrated using results obtained during a 2-day summer experiment in a shallow macrophyte-rich stream. The biological processes in the stream were mainly associated with the macrophyte-biofilm community and the sediment, those in the water being negligible. Oxygen release was confined to the macrophyte-biofilm community, the sediment consuming oxygen both by day and by night. Whole-system gross production and dark respiration occurred at similar rates (6-7g O2 m-2 day-1), net balance being about zero. Inorganic nitrogen was consumed both by the sediment and to a greater extent by the macrophytes, the diel average consumption being 1g N m-2 day-1. 3. The sum of the activity in the macrophyte and sediment chambers corresponded to the overall activity of the stream section as determined by upstream/downstream mass balance. This indicates that the results obtained with the continuous-flow chambers realistically describe the oxygen and the nitrogen metabolism of the stream.
Nitrogen Oxygen In vitro monitoring

"Identification Of Chemical Behaviour Of Chromium In Water By Flow Injection Spectrophotometry"
Gaodeng Xuexiao Huaxue Xuebao 1990 Volume 11, Issue 2 Pages 140-143
Wei, Q.;Wang, S.;Wang, L.

Abstract: A method is described for the sequential determination of Cr(VI) and total Cr in water by flow injection analysis - spectrophotometry. Chromium(VI) was measured directly after treatment with diphenylcarbazide and total Cr was measured after the pre-oxidation of Cr(II) to Cr(VI) in a PbO2 column at 80°C. Calibration graphs were rectilinear from 0.5 to 3.0 mg mL-1. Sample throughput was 120 and 200 h-1 for total Cr and Cr(VI), respectively.
Chromium(VI) Chromium Column Calibration

"Flow Injection Analysis Method For The Indirect Determination Of Cyanide With The Ternary Copper(II)-Chrome Azurol S-CTAMB Complex"
Gaodeng Xuexiao Huaxue Xuebao 1990 Volume 11, Issue 10 Pages 1141-1143
Zhao Shanlin, Zhang Sousong

Abstract: The flow injection analysis method for the indirect determination of cyanides with a ternary complex of Cu(II)-CAS-CTMAB was studied and proposed. The experimental parameters were discussed by means of experiments. The cyanides in the industrial waste water from the procedure in the Chemical Fiber Plant of Fushun were determined. It is shown that this method is simple, sensitive and accurate.
Cyanide Spectrophotometry Indirect

"Kinetic Spectrophotometric Determination Of Trace Nitrite Using A Stop-flow Injection Method"
Gaodeng Xuexiao Huaxue Xuebao 1993 Volume 14, Issue 4 Pages 492-494
Zhang, G.;Liu, S.;He, X.;Shi, H.

Abstract: Based on the catalytic effect of trace nitrite on the oxidation of C. I. Basic Violet 10 by potassium bromate, a new kinetic spectrophotometric method for the determination of nitrite was established using a stop-flow injection technique. Absorbance at 555 nm and 30°C was monitored; the stop-flow time was 50 s and the optical path length was 1 cm. Beer's law was obeyed from 0.24 (detection limit) to 9.0 ng/ml of nitrite. The interferences from over 20 ions were examined. The method was used to determine nitrite in water (sampling frequency 60/h) and gave satisfactory results.
Nitrite Spectrophotometry Kinetic Stopped-flow Catalysis Interferences

"Determination Of Nickel, Copper, And Mercury By Flow Injection Preconcentration Coupled With HPLC"
Gaodeng Xuexiao Huaxue Xuebao 1998 Volume 19, Issue 11 Pages 1746-1748
Akbar, A.;Shen, H.;Xu, G.M.;Yin, X.F.

Abstract: A home designed pressure tight pre-concentration column combined with an HPLC six-port valve was used to interface the FI sorbent extraction pre-concentration system and HPLC. Based on this system, a method for determination of trace amt. of Ni, Cu and Hg in water samples after online derivatization and pre-concentration as their diethyldithiocarbamate complexes has been developed. The sensitivity and selectivity can be further improved by using time programming for absorption measurement. The detection limit 0.16 µg/L, 0.41 µg/L and 1.1 µg/L, and the relativity standard deviation, 3.6%, 4.5% and 3.9%, were found for Ni (II), Cu(II) and Hg(II), respectively.
Nickel Copper Mercury Spectrophotometry HPLC Preconcentration Solid phase extraction

"Automated Determination Of Arsenic, Antimony, Selenium And Mercury In Water"
GIT Fachz. Lab. 1997 Volume 41, Issue 5 Pages 475-476
Sinemus, H.W.;Stabel, H.H.;Kleiner, J.;Radziuk, B.

Abstract: The hydride-forming elements and Hg were concentrated by pumping the sample and the reducing solution (NaBH4 or SnCl2, respectively) into a manifold, entraining the hydride or Hg vapor in Ar and introducing the gas stream into a pyrolytic graphite tube equipped with an Ir-coated platform for AAS determination. The operating program of the automated system is shown. For the determination of As, Sb and Se, samples were collected in fluorinated ethylene/propene or polyethylene terephthalate co-polyester vessels and stabilized with 0.2% HCl, and were treated with 37% HCl, KI, ascorbic acid, hydroxylammonium chloride and sulfamic acid to reduce As and Sb in higher oxidation states or with 37% HCl, sulfamic acid and ammonium sulfate to reduce Se(VI). Samples to be analyzed for Hg were collected in hard glass vessels and stabilized with HNO3/potassium dichromate and H2SO4. Organic Hg compounds were decomposed ultrasonically in the presence of KMnO4 and ammonium persulfate. Hydroxylammonium chloride was added to reduce permanganate before the analysis. Very small amounts of Hg were pre-concentrated on Au/Pt gauze. Characteristic masses for As, Sb and Se were 24, 38 and 45 pg, respectively. Down to 3 ng/l of Hg could be detected.
Mercury Arsenic Antimony Selenium Sample preparation Spectrophotometry Preconcentration Volatile generation Automation Volatile generation

"Application Of Kelgraph To Electrochemical Detectors For Flow Injection Analysis And High Performance Liquid Chromatography"
Gov. Rep. Announce. Index 1983 Volume 83, Issue 2 Pages 4961-4961
Weisshaar, Duane E.

Abstract: The active area of Kel-F graphite composite (Kelgraf) electrodes determined from short time chronoamperometric data agree well with the weight percent of graphite in the composite and with the percent conducting carbon on the surface determined from x-ray photoelectron spectroscopy (XPS). The performance of Kelgraf as an electrode for electrochemical detection in flowing streams is discussed, including the determination of the optimum electrode composition and the linear dynamic range of the detector. The detector was applied to the determination of phenols in groundwater and coal gasification waste water. Detection limits ranged from 3-15 pg for a variety of phenols. No fouling of the electrode was evident. Evidence based on chronoamperometry, XPS, SEM, cyclic voltammetry and capacitance measurements point to the existence of a partial thin film of Kel-F over portions of the graphite sites. The implications of the presence of such a film are also discussed.
Phenols Electrode HPLC

"Study On The Determination Of Magnesium By Flow Injection Analysis - Flame AAS Using A Single-standard-solution Continuous-dilution Calibration Technique"
Guangpuxue Yu Guangpu Fenxi 1990 Volume 10, Issue 1 Pages 38-41
Hou, X.;Xu, P.;Sun, Z.

Abstract: The method is based on that described by Tyson et al (cf. Talanta, 1984, 31, 9). A simple flow injection analysis - flame AAS apparatus was designed and applied to determine Mg in water and geological samples. The absorbance was measured at 285.2 nm. The coefficient of variation is 0.41% and recoveries were 99.3 to 101% when determining 50 to 250 µg of Mg.
Magnesium Spectrophotometry

"Rapid Determination Of Sulfide In Water By Flow Injection Analysis"
Huanjing Huaxue 1983 Volume 2, Issue 3 Pages 64-68
Wang, Lijun; Zhang, Shen; Zhu, Yangming; Wang, Qinsheng

Abstract: Sulfide in water was determined by flow injection analysis (FIA) using methylene blue spectrophotometry with a linear calibration for concentrations in the range 3.5-200 mM. The relative standard deviation was 1.05% for 20 determinations of a 56.0 mM S2- sample. Cr(VI) at <0.5 mM shows no interference in the analysis The method can be used to analyze 60-80 samples/h.
Sulfide Electrode Interferences

"Determination Of Cyanide In Soil And Water By Flow Injection Analysis"
Huanjing Huaxue 1984 Volume 3, Issue 1 Pages 48-52
Cui, Hungbo; Zhu, Zhaohai; Fang, Zhaolun

Abstract: Cyanide in waters and soils is determined by flow-injection analysis using ion-selective electrode method with a AgI-Ag2S membrane electrode. The linear detection range and recoveries are 0.2-10 ppm and 98-102%, respectively; the relative standard deviation is 1.2% at the 1 ppm level. The optimal injection frequency for a sample at 0.2 mg/L was 120 samples/h.
Cyanide Electrode Electrode Optimization

"Application Of Amperometric Flow-through Gold Tubular Detector Determination Of Trace Sulfide Ion By Flow Injection Analysis"
Huanjing Huaxue 1984 Volume 3, Issue 5 Pages 75-79
Ma, Huichang; Yan, Huiyu

Abstract: The amperometric detector using a Au-tubular electrode is suitable for trace sulfide determination in surface water and pulp wastewater at pH > 5-6 and applied external voltage +300 mV. The linear response covers three orders of magnitude in the ppb ppm range, the relative standard deviation is ≤3%, and the detection frequency is 60/h. Interference by phenol and cyanide is insignificant at pH 5-6.
Sulfide Amperometry Electrode Interferences

"Flow Injection Analysis By Ion-selective Electrodes, A Detachable Solid Membrane Chloride Ion-selective Electrode Used In The Determination Of Chloride In Soil Water Extracts"
Huanjing Kexue 1981 Volume 2, Issue 5 Pages 376-380
Gao Zhan; Lu Mingyuan

Abstract: The flow injection mol. determine the Cl- contents at 10^-3 - 10^-1 M in leachates with volume >10 mL with relative standard deviations 1-2%. The response potentials 50-150 mV are linearly related to Cl- concentrations <10-3 - 1 x 10^-1 M. For leachate samples containing Cl-, the method yields Cl- contents 0.12 and 0.98% compared to 0.14 and 0.92% determined by a volumetric method.
Chloride Electrode Method comparison

"Determination Of Trace Arsenic In Water By Flow Injection Hydride Generation Atomic Absorption Spectrometry"
Huanjing Wuran Yu Fangzhi 1998 Volume 20, Issue 4 Pages 35-37
Xu Guangming A.Ali Lu Xiaohua Yan Xuefeng

Abstract: A method for determination of trace As in water by flow injection hydride generation atomic absorption spectrometry was presented, L-cysteine was used as pre-reductive agent to reduce As(V) to As(III). The linear range was 0-15.0 µg L-1, linearly dependent coefficient γ 0.9999°C, detection limit 0.05 µg L-1, relative standard deviation 1.8%, and recovery of As 95-104%.
Arsenic Spectrophotometry

"Water Analysis In The UK Using FIAstar"
InFocus 1985 Volume 8, Issue 1 Pages 4-NA
Hemmings, P.;Shaw, A.

Abstract: NA
Alkalinity Spectrophotometry Tecator

"Improved Determination Of Aluminum Species In Waters Using FIA Separation-fluorimetric Detection Techniques"
Int. J. Environ. Anal. Chem. 1993 Volume 50, Issue 3 Pages 161-171
B. Fairman a; A. Sanz Medel

Abstract: A flow injection fluorimetric method for the speciation of labile monomeric Al in water was compared with a standard spectrophotometric method (cf. Dougan and Wilson, Analyst, 1974, 99, 413). Water was injected into a stream of dilute NaCl solution (1 ml/min) which was either passed through an ion-exchange column (5 cm x 3 mm) of Amberlite IR-120 (for measurement of non-labile monomeric Al) or diverted past the column (for measurement of total monomeric Al). The column eluate or diverted stream was merged with a stream of 8-hydroxyquinoline-5-sulfonic acid/hexadecyltrimethylammonium bromide in 0.4% 1,10-phenanthroline monohydrate/H2O/sodium acetate trihydrate buffer of pH 6 (0.45 ml/min) and passed through a reaction coil (2 m x 0.5 mm). The fluorescence intensity of the resulting solution was measured at 500 nm (excitation at 390 nm). The difference in peak heights obtained for samples which did or did not pass through the column was proportional to the concentration. of labile monomeric Al. The calibration graph was rectilinear for 1-10 000 µg/l and the RSD at 50 µg/l was 1.4%. The method had better precision, detection limit, analysis time, sample size and column characteristics than the standard method.
Aluminum Fluorescence Amberlite 8-hydroxyquinoline-5-sulfonic acid Speciation Standard method Method comparison

"Use Of Segmented Micro-continuous-flow Analysis And FIA In Water Analysis"
Int. Lab. 1990 Volume 20, Issue 7 Pages 33-34
Straka, M.R.

Abstract: Recent developments in these techniques are summarized. The term 'micro-continuous' flow analysis is used to mean that in which the i.d. of the tubing is reduced from 2.4 mm to 1 mm. This change, together with electronic control of the timing, and hence the size, of the segmenting air bubbles, and detector cells that do not require de-bubbling of the analytical stream before spectrophotometry, all contribute to lower dispersion. This permits faster sampling rates (up to 200 h-1) and also reduces the required volume of sample and reagents. The relative merits of µsegmented and non-segmented flow injection analysis are compared, so that the appropriate technique for a chosen application may be selected.
Segmented flow Detector

"Online Trace Enrichment For Determination Of Aldicarb Species In Water Using Liquid Chromatography With Post-column Derivatization"
J. AOAC Int. 1986 Volume 69, Issue 6 Pages 985-989
Chaput D.

Abstract: Water samples were filtered (0.45 µm membrane) and degassed with He, and then applied to a loop-mounted cartridge concentration column (3.7 cm x 4.6 mm) of LiChrosorb RP-8 (10 µm) preceding an analytical column (25 cm x 4.6 mm) of LiChrosorb RP-8 (10 µm) operated at 35°C. Gradient elution from aqueous 18 to 60% methanol and back to aqueous 18% methanol was effected at a flow rate of 1.5 mL min-1. Aldicarb and its sulfoxide and sulfone in the eluate were hydrolyzed with KOH to methylamine and the fluorophore was formed with phthalaldehyde and 2-mercaptoethanol (cf. Krause, Ibid., 1980, 63, 1114). The fluorescence was measured at 418 nm with excitation at 365 nm. The minimum detection limit was <70 ng L-1 for each of the three compounds.
Aldicarb HPLC Fluorescence Post-column derivatization

"Continuous-flow Vapor Generation For Inductively Coupled Argon Plasma Spectrometric Analysis. 1. Selenium"
J. AOAC Int. 1990 Volume 73, Issue 3 Pages 404-410
Tracy ML, M&ouml;ller G.

Abstract: Sample (~1.5 g of solid or ~10 mL of liquid) is wet ashed with HNO3, H2SO4 and HClO4 at ~310°C; details are presented for treatment of different samples. The digest is cooled to room temp., 5 M HCl is added and the solution is diluted. In a simple continuous-flow manifold, sample solution is mixed with 12 M HCl and then 0.6% NaBH4 solution The H2Se produced is separated off by a standard pneumatic neublizer, and Se is determined by ICP-AES at 196.090 nm. The detection limit is 0.4 µg l-1, or 4 µg kg-1 for a nominal 1-g sample. The calibration graph is rectilinear for 4 mg kg-1. The method has been applied to biological tissues and fluids and to water. Results show good agreement with those by AAS and NAA.
Selenium Spectrophotometry Dilution Nebulizer Detection limit Calibration

"Automation Of A Flow Injection System For Multispeciation"
J. Autom. Methods Manag. Chem. 1986 Volume 8, Issue 2 Pages 70-74

Abstract: The flow injection system is shown in a diagram, and has been used to determine Cr(III) and Cr(VI) in aqueous solution The sample is mixed with H2SO4 and the resulting solution is split into two streams; one is mixed with a solution containing Ce(IV) to oxidize Cr(III) to Cr(VI) and the other is mixed with 1,5-diphenylcarbazide reagent. After passage through separate reactor coils the streams are combined and a plug with two reaction zones is formed in a third reactor coil. This plug is monitored at 540 nm; the two peaks detected correspond to Cr(VI) and total Cr in the sample. The calculation of the results is described in detail.
Chromium(III) Chromium(VI) Spectrophotometry Review Speciation

"Flow Injection Analysis Of Water. 1. Automatic Preconcentration Determination Of Sulfate, Ammonia And Iron(II)/iron(III)"
J. Autom. Methods Manag. Chem. 1993 Volume 15, Issue 4 Pages 141-146

Abstract: A simple flow injection manifold (illustrated) is described for the sequential determination of sulfate, NH4+ and Fe2+/Fe3+ in industrial water. For the determination of sulfate, a turbidimetric method using BaCl2 as derivatizing reagent was used. For NH4+, the Berthelot reaction (i.e., the reaction between hypochlorite and phenol in the presence of NH4+ in a basic medium) was used and the absorbance of the colored product was measured at 636 nm. For the speciation of Fe, Fe2+ was determined by treating a portion of sample solution with 1,10-phenanthroline and the absorbance of the orange complex formed was measured at 510 nm. For the determination of total Fe another portion of sample solution was passed through a copperized-cadmium redox column to reduce Fe3+ to Fe2+ followed by reaction with 1,10-phenanthroline. The concentration. of Fe3+ was calculated by difference. A micro-column of a suitable ion-exchange material was used for the online pre-concentration. of each analyte prior to injection. Results are tabulated. The system may be fully automated.
Sulfate Ammonia Iron(2+) Iron(III) Spectrophotometry Turbidimetry Preconcentration Speciation

"Flow Injection Analysis Of Water. 2. Integrated System For Automatic Multi-determination"
J. Autom. Methods Manag. Chem. 1993 Volume 15, Issue 4 Pages 147-150

Abstract: The automation of an integrated flow injection system (see previous abstract) for the determination of ammonia, sulfate and Fe2+/Fe3+ in industrial water is described. The system was designed for the determination of individual analytes in a large batch of samples, as manual selection of parameters and units for each individual analyte is required.
Sulfate Ammonia Iron(2+) Iron(III) Multidetection

"Automatic Calibration For Online Process Monitoring In Continuous-flow Systems"
J. Autom. Methods Manag. Chem. 1995 Volume 17, Issue 1 Pages 17-20

Abstract: Automatic calibration in a continuous-flow system was achieved by incorporating a flow gradient unit in the sample channel. The unit (cf. Anal. Chim. Acta, 1990, 239, 211) was controlled via a switching value so that a concentration gradient of the standard was delivered into the system, with the concentration varying with time after the flow-rate gradient was started. This enabled the calibration to be checked as frequently as was required. The system was applied to the determination of hydrazine (I) in water. The sample stream (1.4 ml/min) was merged with a stream (0.4 ml/min) of 0.5 M HCl and then with a stream (0.4 ml/min) of 4% 2,4-dimethylaminobenzaldehyde in methanol/HCl and passed through a reaction coil (625 cm x 0.8 mm i.d.) before detection at 460 nm (manifold illustrated). The calibration graphs generated using a standard I solution of 0.5, 1 or 1.5 µg/ml were linear. The RSD was 1.5%. The results for the analysis of I in water using a 1 µg/ml standard solution for calibration after every three samples are presented.
Hydrazine Spectrophotometry Calibration Gradient technique Process monitoring

"The Principles Of Flow Injection Analysis As Demonstrated By Three Lab Exercises"
J. Chem. Educ. 1979 Volume 56, Issue 10 Pages 677-680
Hansen, E. H.; Ruzicka, J.

Abstract: Three lab. experiments are described to illustrate a continuous-flow anal. technique, in which samples are injected into a continuously moving stream. The sample then mixes with and reacts with reagents in the stream (or added downstream) prior to its passage through a detecting device. Significant factors in this flow injection analysis technique are sample injection, reproducible timing, and controlled dispersion. The described experiments are for determination of chloride in water samples, determination of phosphate in output from a chromatography column, and titration of a strong acid with a strong base.
Acids Bases Chloride Phosphate Phosphates Spectrophotometry Education Review Titrations

"Investigation Of Temperature Effects On Dispersion In A Flow Injection Analyzer. A Laboratory Exercise."
J. Chem. Educ. 1988 Volume 65, Issue 7 Pages 645-647
C. L. M. Stults, A. P. Wade and S. R. Crouch

Abstract: A lab. experiment is described that illustrates the effect of temperature upon dispersion in a flow injection analyzer. The experiment shows that sample dispersion decreases with increasing temp.
Alizarin red 4-Nitrophenol Spectrophotometry Computer Dispersion Education Reverse Temperature Theory

"Comparison Of Continuous Flow Analysis Techniques - A Laboratory Exercise"
J. Chem. Educ. 1989 Volume 66, Issue 12 Pages 1060-1062
C. L. M. Stults , Paul R. Kraus , S. K. Ratanathanawongs , Chas. J. Patton and S. R. Crouch

Abstract: A lab. experiment is described that demonstrates the differences between air-segmented continuous-flow and nonsegmented continuous-flow (or flow-injection) anal. The determination of chloride and nitrite are used to demonstrate these differences. The dispersion characteristics of the 2 techniques are compared by monitoring the absorbance of phenol red at 540 nm.
Nitrite Spectrophotometry Education Air segmentation

"A Microconduit Flow Injection Analysis Demonstration Using A 35-mm Slide Projector"
J. Chem. Educ. 1990 Volume 67, Issue 3 Pages 262-263
Ian D. McKelvie, Terence J. Cardwell and Robert W. Cattrall

Abstract: A 35-mm projection demonstration of flow injection analysis is described that combines the advantages of a highly magnified view of the sample zone as it undergoes dispersion and the ability to show a 3-line flow injection analysis manifold. The microconduit slide described can be used to illustrate any 3-line flow injection analysis in which the analyte yields a strongly colored product. The benefits of stopped-flow injection analysis can be shown using the described arrangement.
Bromothymol blue Spectrophotometry Microfluidic Education

"Determination Of Lead In Aqueous Systems By Flow Injection Spectrophotometry"
J. Chem. Soc. Pak. 1996 Volume 18, Issue 1 Pages 25-28
Nabi, A.;Yaqoob, M.;Khatoon, S.

Abstract: A schematic diagram of the flow injection manifold is given. Sample (30 µL) was injected into an NH3/2.1 mM ammonium citrate/10 µM-sodium citrate stream and merged 15 cm downstream with a 1 mM Na2S/0.1 mM NH3 stream. After mixing in a 30 cm coil, the absorbance of the solution was measured at 420 nm. All flow-rates were 1.2 ml/min. The sample throughput was 60 samples/h. The calibration graph was linear from 0.1-10 mg/dl of Pb. The overall repeatability RSD was 1.5%. The effect of diverse ions on the Pb determination are discussed. Cd(II), Co(II) and Fe(III) interfered significantly but could be removed by masking agents.
Lead Spectrophotometry Interferences

"Derivatization Of Alkyl Halides, Acid Chlorides And Other Electrophiles With Polymer-immobilized 8-amino-2-naphthoxide"
J. Chromatogr. Sci. 1988 Volume 26, Issue 10 Pages 501-512
Colgan, S.T.;Krull, I.S.;Dorschel, C.;Bidlingmeyer, B.A.

Abstract: Details are given for the normal- or reversed-phase HPLC determination of the cited compounds, with isocratic or gradient elution and UV, fluorimetric or amperometric detection. The 8-amino-2-naphthoxide was immobilized on AG1-X8 resin (Cl- form; Bio-Rad), which was packed into a column (3.3 cm x 3.9 mm) for use in pre- or post-analytical column derivatization. The acid chlorides react fast enough to allow online derivatization. Detection limits were in the sub-ppb range. The method was applied in the determination of cis- and trans-1,3-dichloropropene in water.
1,3-Dichloropropene HPLC Amperometry Fluorescence Spectrophotometry Immobilized reagent Post-column derivatization PPB

"Continuous-flow Photocatalytic Degradation Of Carbaryl In Aqueous-media"
J. Environ. Sci. Heal. 1993 Volume 28B, Issue 4 Pages 431-435
Peris-Cardells, E.; Terol, J.; Mauri, A. R.; de la Guardia, M.; Pramauro, E. (SFS)

Abstract: The photocatalytic degradation of carbaryl, present in aqueous solutions containing suspended TiO2 particles, has been studied in a continuous flow system, using a polytetrafluoroethylene photochemical reactor, equipped with an UV lamp. In order to optimize the process the effect of pH, catalyst and pesticide concentration, and irradiation time have been evaluated, working in the best conditions, the measured half-life of carbaryl was 26 seconds. More than 99% of carbaryl present in solutions containing 0.2 mg L-1 of pesticide decomposes after less than 1 minute irradiation.
Carbaryl Photochemistry Catalysis Optimization

"Flow Injection Analysis Based On Volumetric Analysis-reaction With Buffer Solutions"
J. Flow Injection Anal. 1984 Volume 1, Issue 2 Pages 2-12
Nobuhiko Ishibashi, Toshihiko Imato

Abstract: Various approaches to acid base reactions in FIA are discussed.
Amino Acids Hardness Electrochemical analysis Spectrophotometry Reactor

"Development Of Micro Spectrophotometric Detector Using Light Emitting Diode And Photo Diode, And Its Application To Flow Injection Analysis"
J. Flow Injection Anal. 1984 Volume 1, Issue 2 Pages 21-29
Takashi KORENAGA and Hisayoshi IKATSU

Abstract: A µspectrophotometric detector was prepared for an application of flow injection analysis (FIA). It was made of a light emitting diode, a silicone photo diode, a logarithmic amplifier, etc. It was relatively small (5-cm height, 10-cm depth, 20-cm width). The detector was tested by an analysis of total iron in water samples with bathophenanthroline disulfonic acid disodium salt. The reproducibility was obtained at a concentration range of 0-1 mg-Fe/L. The limit of detection and precision were 0.02 mg-Fe/L and l.5 %, respectively. The results obtained by this method were compared satisfactorily with those obtained by the atomic absorption spectrophotometric method. The detector was also applied as a detector of FIA by attaching a flow through cell. In the single line FIA system, various concentrations of aqueous oxalate solutions were reproducibly detected with an acidic permanganate reagent solution. The precision with the method was 0.5 %. From these conclusions, the detector developed here was considered acceptable in a µFIA system. It can be advanced to a highly sensitive FIA detector by using a laser beam and a flow through cell having long light path.
Iron Spectrophotometry Apparatus Light emitting diode Photodiode

"Flavin Mononucleotide Sensitized And Polyoxyethylene (20) Sorbitan Trioleate Micelle-enhanced Chemiluminescence For Sulfite Determination By FI Method"
J. Flow Injection Anal. 1984 Volume 1, Issue 2 Pages 31-39
Masayoshi Kato, Masaaki Yamada*, and Shigetaka Suzuki

Abstract: The weak emission arising from the excited sulfur dioxide produced by the oxidation of sulfite by the acidic permanganate solution is sensitized by flavin mononucleotide; the sensitized emission is further enhanced by means of Tween 85(polyoxyethylene(20) sorbitan trioleate) surfactant micelles. This chemiluminescence system is used to determine sulfite by flow injection method. Under conditions of 2 x 10^-6 M KMnO4 (pH 2.5), 1 x 10^-3 M flavin mononucleotide containing 10 g/L Tween 85 surfactant, and flow rates of each reagent (5 mL/min) and carrier stream (12 mL/min), the lower limit of determination is 2 x 10^-7 M (200 µL sample injection), the sampling rate is 300/h, and the relative standard deviation is 4.8 % for 1 x 10^-6 M sulfite (n=10).
Sulfite Chemiluminescence Micelle

"Optimization Of Flow Injection Analysis For The Determination Of Inorganic Phosphates: Effect Of The Reaction Temperature"
J. Flow Injection Anal. 1984 Volume 1, Issue 2 Pages 40-48
Yoshinobu Baba, Hisanobu Hirano, Norimasa Yoza and Shigeru Ohashi

Abstract: The FIA System has been optimized for the sensitive aa quantitative determination of inorganic phosphates. Two variables, residence time and reaciton temperature, were taken into account. Reaction temperature was found to play an important role in improving the sensitivity and quantitation. At the maximum sensitivity the sampling rates were 112 samples/h for orthophosphate and 105 samples/h for pyrophosphate, respectively.
Phosphate Spectrophotometry Optimization Temperature

"Successive Automation On The Measurement Of Chemical Oxygen Demand By Flow Injection Analysis"
J. Flow Injection Anal. 1985 Volume 2, Issue 1 Pages 5-14
Takashi Korenaga

Abstract: COD analysis is successfully coverted to a flow injection approach.
Chemical oxygen demand Spectrophotometry Method comparison

"Highly Sensitive Chromogenic Reagents For The Use In Flow Injection Analysis"
J. Flow Injection Anal. 1985 Volume 2, Issue 1 Pages 15-27
Genkichi NAKAGAWA and Hiroko WADA

Abstract: Design and synthesis of new chromogenic reagents for the use in flow-injection analysis, and their application to the determination of calcium and magnesim, iron and copper in water samples and sera are described. The flow-injection analysis of fluoride ion with La-Alizarin complexone is also presented.
Calcium Copper Fluoride Iron Magnesium Spectrophotometry Tecator Chromogenic reagent

"Flow Injection Analysis Of Silicic Acid. Application To Study The Polymerization Of Silicic Acid"
J. Flow Injection Anal. 1985 Volume 2, Issue 1 Pages 30-39
Takushi YOKOYAMA and Toshikazu TARUTANI

Abstract: Flow injection analysis was developed for the spectrophotometric determination of molybdate reactive silicic acid (MRSA) in the presence of polysilicic acid. A sample solution c.a. 0.07 mL) introduced meets an acidic molybdate reagent stream from another channel and flows together into a reaction tubing. The temperature of the reaction tubinq must be maintained at 90°C. Residence time of the sample in the reaction tubing is about 1 min. The absorbance of molybdosilicic acid is monitored at 450 nm. MRSA in the concentration up to 50 ppm (Si) can be determined at a sampling rate of 36 sarnples/h with good precision.
Silicic acid Spectrophotometry

"Flow Injection Analysis For Phosphorus Compounds"
J. Flow Injection Anal. 1987 Volume 4, Issue 2 Pages 86-97
Norimasa YOZA,* Tokunori YOKOTA,* Annika SJODIN,** and Jurgen MOLLER**

Abstract: A review is presented, with 26 references, of flow injection and HPLC methods for the determination of inorganic and biochemical P. Various Mo reagents are investigated for the determinations and the design of a flow system that can be used convertibly for both flow injection analysis and HPLC is described.
Phosphorus Spectrophotometry Review Speciation

"Sanwich FIA Simultaneous Multidetermination Of Cationic Species In Waters"
J. Flow Injection Anal. 1995 Volume 12, Issue 2 Pages 194-208
Araujo, A.N.;Lima, J.L.F.C.;Saraiva, M.L.M.F.S.

Abstract: The use of the sandwich technique to perform different biparametric determinations of cationic species in waters is described in order to exploit its general performance in which sampling rate, reagent consumption and analytical range is concerned. To achieve this aim a laboratory-made 14 ports rotatory valve is used. Its construction and working mechanism, namely the possibility of this valve enabling the insertion of a sample plug sandwiched between two plugs of different reagents into the carrier stream, are outlined. With this valve three manifolds were developed: Fe(II)/total iron, Cr(VI)/total iron, Al/Cu by normal and reverse FIA modes determinations, respectively, with sampling rates varying between 60 and 120 h-1. Comparative analysis of the results obtained with proposed methodologies and those of the reference methods were also performed showing correlation coefficients varying between 0.988 in determinations for total iron with system for determination of Fe(II)/total iron, and 0.999 in determinations of Cr(VI) and Cu (by reverse FIA mode). The results obtained showed a relative standard deviation lower than 3.7%.
Simultaneous analysis Sandwich technique

"Analysis Of Oxothio Arsenic Species In Soil And Water"
J. Prakt. Chem. Chem. Ztg 1996 Volume 338, Issue 1 Pages 55-59
Georg Schwedt, Melanie Rieckhoff

Abstract: Arsenic species in alkaline extracts of sulfidic and arsenic slags as well as in water in mines were analyzed by ion chromatography and capillary zone electrophoresis. The total arsenic was determined in both kinds of samples by FIA-hydride AAS, in the slags after microwave induced pressure digestion, and in the untreated solid samples also by RFA. Arsenate, arsenite and monothioarsenate ions could be identified and quantified as stable arsenic species.
Arsenate ion Arsenothioate ion Arsenite Sample preparation Spectrophotometry Speciation Volatile generation Volatile generation

"Spectrophotometric Determination Of Calcium By Flow Injection Analysis"
Jilin Daxue Ziran Kexue Xuebao 1984 Volume 22, Issue 3 Pages 113-117
Wei Qingxun

Abstract: Ca determination by flow injection-absorption spectrophotometry is based on an exchange reaction between Ca ion and the Zn complex of EGTA. In the presence of 2.0 x 10^-4 M Zincon and 4.0 x 10^-4 M Zn-EGTA, the linear determination range is 4-32 ppm with a sampling rate of 100 samples/h. The results from natural water anal. are in good agreement with atomic absorption spectrophotometry.
Calcium Spectrophotometry Method comparison

"Determination Of Nitrogen, Phosphorus And Anionic Surfactant In Water By Flow Injection Analysis"
Kankyo Gijutsu 1986 Volume 15, Issue 7 Pages 525-530

Abstract: The application and use of flow injection analysis in the determination of trace nitrogen, phosphorus, and anionic surfactants in water are discussed.
Surfactants, anionic Nitrogen Phosphorus

"Determination Of Manganese By Malachite Green-periodate Catalytic Reaction With Concentrated Reagents And Its Application To Flow Injection Analysis"
Kenkyu Hokoku 1986 Volume 49, Issue 2 Pages 147-152
Kawakubo, S.;Fukasawa, T.;Iwatsuki, M.;Fukasawa, T.

Abstract: Mn was determined by its catalytic action on the redox reaction in malachite green-IO4- system at pH 3.3. The induction period could be eliminated with concentrated solutions of the reagents at higher temperature (48°C). From the decrease in absorbance at 615 nm, 2-200 ng Mn was determined by the batchwise method, whereas 0.03-2 ng Mn/20 µL by flow-injection analysis. (SFS)
Manganese Spectrophotometry Catalysis Heated reaction Indirect

"Chemical Sensors For Water Quality Analysis"
Kogyo Yosui 1991 Volume 395, Issue 1 Pages 80-89
Asano, Y.;Itoh, S.

Abstract: A review is presented, with 12 references, with discussion of pH, redox and ion electrodes, BOD sensors and flow injection analysis using chemical sensors.
Electrode Sensor pH Redox Review

"Turbidimetric Determination Of Sulfate With A Miniaturized Manifold On A Non-segmented High Speed Continuous-flow System"
Lab. Pract. 1978 Volume 27, Issue 10 Pages 863-865
Basson, W.D.;Van Staden, J.F.

Abstract: SO42- 50-200 mg/L was determined in water (200 samples/h) by adding BaCl2 solution and measuring the turbidity at ?15 and 420 nm. A buffer solution containing EDTA di-Na salt and NH4OH was used. (SFS)
Sulfate Turbidimetry

"Matrix Influence In Water Analysis. Determination Of Ammonia-nitrogen According To DIN 38406, Part 23, By Flow-analysis Methods"
LaborPraxis 1993 Volume 17, Issue 5 Pages 48-50
Stadler, M.;Neidhart, B.;Rueter, J.;Papke, G.;Winter, B.

Abstract: Determination was carried out by continuous-flow analysis and FIA in accordance with a DIN method based on absorbance measurement of a NH4+ complex with hypochlorite/salicylate. Equimolar amounts of ethyl-, isopropyl-, n-butyl, dimethyl-, diethyl-, di-isopropyl- and triethyl-amine interfered. In the continuous-flow method, interference can be reduced by preliminary purification of the sample by dialysis.
Ammonia, nitrogen Spectrophotometry Interferences Dialysis Standard method

"Flow Injection Analysis For The Determination Of Ammonium In Water"
LaborPraxis 1997 Volume 21, Issue 4 Pages 72-75
Desor, M.

Abstract: A description is given of the DIN 38406 method for determining ammonium nitrogen in water by FIA. Samples were filtered (0.45 µm) and adjusted to a pH of 3. Portions were injected into a carrier stream of water which then mixed with alkaline EDTA solution. The liberated NH3 diffused through a semi-permeable membrane into an acceptor solution of bromocresol violet, bromothymol blue and cresol red, adjusted to a pH of 5.3, and the absorbance was measured at 590 nm. Calibration graphs were linear from 10^-1000 µg/l N, with a detection limit of 5 µg/l. At 500 µg/l, the RSD was 1.02% (n = 12). The throughput was 60 samples/h. A complete analytical system for this is the Lachat QuikChem Model 8000 (Zellweger Analytics GmbH, Munich, Germany), including a software package for control and evaluation, for use with a PC and Windows. The system can be combined with ion chromatography measurements.
Ammonium, nitrogen Sample preparation Spectrophotometry Gas diffusion Membrane Standard method Lachat

"Determination Of Trace Vanadium By Reversed-flow Injection Catalytic Spectrophotometry"
Lihua Jianyan, Huaxue Fence 1998 Volume 34, Issue 3 Pages 101-103
Liu Xiuping and Zhang Zhiqi

Abstract: A method for the determination of trace V by reversed-flow injection catalytic spectrophotometry was established. The method is based on the catalytic action of V on the oxidation-decoloration of rhodamine B by NaBrO3 with citric acid as activating agent in the presence of OP in H2SO4 medium. The interferences of Fe(III) and Cu(II) were eliminated by using cation resin exchange. The linear range was 10^-200 µg L-1, the detection limit 1.9 µg L-1, and the RSD 1.5%. The method was used for the determination of trace V in water samples with a recovery 90-104%.
Vanadium Ion exchange Spectrophotometry Catalysis Reverse Interferences Resin

"Determination Of Trace Copper By Flame Atomic Absorption Spectrometry Coupled With Flow Injection Online Coprecipitation Preconcentration"
Lihua Jianyan, Huaxue Fence 1998 Volume 34, Issue 6 Pages 246-255
Jin Xin, Liu Jinsong, Chen Hengwu and Mao Xueqin

Abstract: A method for the determination of trace Cu by FIA-FAAS online co-precipitation pre-concentration was presented. FIA online co-precipitation technique for the pre-concentration of trace Cu(II) with DDTC-Ni2+ as co-precipitating carrier was hyphenated with FAAS determination The co-precipitation was carried out in 0.3 M HNO3 medium, the ppt. was collected in a knitted reactor, and the ppt. was dissolved by Me iso-Bu ketone (MIBK) and transferred directly into the nebulizer burner system of a FAA spectrometer. The detection limit (3s) was 0.2 µg L-1, the linear range 0-0.08 mg L-1, and the relative standard deviation 3.0%. The method was applied to determine trace Cu in environmental and biological standard reference materials, and water samples with satisfactory results.
Copper Spectrophotometry Preconcentration Reference material Coprecipitation Diethyldithiocarbamate Knotted reactor MIBK

"Determination Of Arsenic And Selenium By Injection Combined With Cold-trap Collection Of Hydride And Continuous-flow Hydride Atomic Absorption Technique"
Magy. Kem. Foly. 1996 Volume 102, Issue 3 Pages 248-256
Siska, R.;Borszeki, J.;Gegus, E.

Abstract: Continuous-flow and flow injection hydride-generation AAS methods for the determination of As and Se are described, which involve collection of hydrides in a cold trap (diagrams of manifolds given). The detection limits were 10^-20 pg/ml. The results obtained for international standards agreed with the internationally accepted values. Reproducibility was good. The methods were applied to environmental materials (food and water).
Arsenic Selenium Spectrophotometry Cold trap Reference material

"Reliable And Sensitive Method For Determination Of Microcystins In Complicated Matrices By Frit-fast Atom Bombardment Liquid Chromatography/mass Spectrometry"
Nat. Toxins 1995 Volume 3, Issue 1 Pages 41-49
Kondo F, Ikai Y, Oka H, Matsumoto H, Yamada S, Ishikawa N, Tsuji K, Harada K, Shimada T, Oshikata M, et al.

Abstract: A reliable and sensitive method for determination of hepatotoxic microcystins in complicated matrices by frit-fast atom bombardment liquid chromatography/mass spectrometry (Frit-FAB LC/MS) is described. Immonium ions of constituent amino acids, which were obtained together with molecular ion species by FAB mass spectral analysis of standard microcystins RR, YR, LR, and [D-Asp3] and [Dha7]microcystins LR using flow injection system composed of Frit-FAB probe, showed potential for reliable identification of microcystins by Frit-FAB LC/MS. Frit-FAB LC/MS using a microbore column provided not only the baseline separation of standard microcystins RR, YR, and LR but 200-fold higher sensitivity than that using conventional column. Furthermore, when a selected ion monitoring (SIM) technique was used, the detection limits of microcystins RR, YR, and LR were 300, 350, and 400 pg, respectively, at a signal-to-noise ratio of 5:1, and calibration curves of each microcystin showed a linear relationship from 2 ng to 50 ng. Finally, identification and quantitative analyzes of microcystins in water samples were carried out.
Microcystin RR Microcystin YR Microcystin LR [D-Asp3]Microcystin LR [Dha7]Microcystin LR Mass spectrometry

"Flow Injection Spectrophotometric Determination Of Copper Based On The Solvent Extraction Of The Ion Associate Of Dibromocuprate(I) With Cationic Dyes"
Nippon Kagaku Kaishi 1991 Volume 1991, Issue 6 Pages 795-802
Motomizu, S.;Korechika, K.

Abstract: The method was applied to water. Optimum results were obtained by using an ion associate formed between CuBr2- and PEP+ [the propyl derivative of 4-(4-diethylaminophenylazo)-N-alkylpyridinium] extracted into chlorobenzene with a carrier stream of 0.02 M ascorbic acid and a reagent stream containing 0.4 mM PEP+ and 0.03 M KBr (pH 5). A PTFE porous membrane was used to separate the organic phase, and a 3-m dilution coil was used to separate anionic surfactants from the Cu peak at 575 nm. A rectilinear calibration graph was obtained up to 30 µM. The coefficient of variation was 0.7% for 1 µM (n = 11), and the detection limit was 20 nM.
Copper Spectrophotometry Sample preparation Membrane Surfactant Solvent extraction Optimization

"Flow Injection Determination Of Parts Per Trillion Levels Of Cobalt(II) In Water By The Use Of Contact Catalytic Reaction"
Nippon Kagaku Kaishi 1983 Volume 1983, Issue 7 Pages 1023-1027
Maekoya, C.;Mizuniwa, F.;Usami, K.;Osumi, K.

Abstract: The reaction coil (5 m x 1 mm i.d.) was operated at 40°C and was fed with 0.15 M NaCl - 0.015 M Na tartrate at 1 mL min-1 and with 0.01 M Tiron and 0.01 M H2O2 each at 0.2 mL min-1. A 2 mL sample of the water was injected. A rectilinear calibration graph was obtained for 5 to 200 pg mL-1 of Co(II), with a detection limit of 2 pg and a coefficient of variation of 7.8% at 5 pg mL-1. Calcium, Mg, Cr(III), Mn, Fe, Ni and Cu did not interfere at 200-fold concentration. compared with Co(II)
Cobalt(II) Spectrophotometry Interferences Catalysis Heated reaction Tiron PPT

"Acceleration Effect Of Alcohols On Ion Association Of Molybdophosphate With Malachite Green And Its Use In The Sensitive Flow Injection Determination Of Phosphate"
Nippon Kagaku Kaishi 1991 Volume 1991, Issue 12 Pages 1624-1637
Motomizu, S.;Yasuda, Y.;Oshima, M.

Abstract: The effects of methanol, ethanol, propanol and anionic surfactants on the reaction of molybdophosphate with malachite green (C.I. Basic Green 4; I) was investigated. The use of a surface active agent and 25% ethanol can reduce baseline drift in flow injection analysis (FIA); the addition of ethanol also improves the linearity of calibration graphs. With use of 0.11 M Mo(VI), 1.26 M H2SO4, 0.2 mM I, 25% ethanol and 16% Aerosol 22, orthophosphate could be determined in water by FIA, from 1 to 500 ppb.
Phosphate PPB Sensitivity

"Computerized Continuous Monitoring And Analysis Of Ozone In Solution"
Ozone Sci. Eng. 1996 Volume 18, Issue 5 Pages 469-476
A. Kerc; A. M. Saatci

Abstract: This paper presents a method for continuous monitoring of ozone in water by using the Indigo colorimetric technique. The details of an instrument developed and used for this purpose are explained. Data obtained using the continuous ozone reading equipment in monitoring the ozone levels are presented. The instrument also can be used to measure the decay of ozone in ozonated waters, continuously giving a very accurate measure of ozone decay coefficients. 8 References
Ozone Spectrophotometry Computer

"Immobilisation And Characterisation Of Phenylethanol Dehydrogenase From Lactobacillus Kefir And Its Application In A Flow Injection Analysis System"
Process Biochem. 1995 Volume 30, Issue 1 Pages 49-55
Leman Tarhan*, Werner Hummel

Abstract: Phenylethanol dehydrogenase was isolated from Lactobacillus kefir, and some kinetic parameters and properties of native and immobilized phenylethanol dehydrogenase on modified DEAE-Cellulose, Bioran, Mobitec, and VA-epoxy were investigated. The activity of immobilized phenylethanol dehydrogenase was examined in a flow injection analysis system in relation to the concentration of diacetyl in water and beer.
Diacetyl Immobilized enzyme Kinetic

"Jet Separator Membrane Introduction Mass Spectrometry For Online Quantitation Of Volatile Organic Compounds In Aqueous Solutions"
Rapid Commun. Mass Spectrom. 1993 Volume 7, Issue 10 Pages 935-942
L. E. Dejarme, S. J. Bauer, R. G. Cooks, F. R. Lauritsen, T. Kotiaho, T. Graf

Abstract: A new technique is described for the direct detection of volatile organic compounds present in aqueous solutions at levels in the parts per trillion range. The sample is enriched in analyte in two consecutive stages; one utilizes a semi-permeable membrane interface and the other a jet separator. The analyte solution is sampled as it flows coaxially over a semi-permeable capillary membrane, the interior of which is continuously purged by helium. The permeate is pneumatically transported to the mass spectrometer via a jet separator, which is used to remove excess helium and water from the analyte vapor stream. Data are reported for two instruments; in one the membrane/jet separator system is interfaced to a single quadrupole mass spectrometer via a custom-built metal jet separator with a variable capillary gap. In the second, an ion-trap mass spectrometer is used in conjunction with a conventional fixed-gap quartz jet separator. Typical analyte response times are 2-5 min at ambient temperature, and flow injection methods are used for sample delivery. Direct comparisons, made under identical instrumental conditions, show that the jet separator system displays even lower detection limits than a conventional direct-insertion membrane probe. Detection limits in the range 30 parts per trillion to a few parts per billion are observed for selected volatile organic compounds and the response is linear over 3 orders of magnitude. [References: 31]
Organic compounds, volatile Mass spectrometry Mass spectrometry Mass spectrometry Membrane

"Simultaneous Determination Of Urea- And Ammonia-nitrogen In Soil Extracts And Water By High Performance Liquid Chromatography"
Soil Sci. Soc. Am. J. 1988 Volume 52, Issue 4 Pages 969-973
A. Abshahi, S. S. Goyal and D. S. Mikkelsen*

Abstract: A HPLC system is described that utilizes three columns, viz, a guard column of Pellicular refill media - silica, a column of Partisil 10 SCX cation-exchange resin for separation of NH4+, and a column of urease - Nucleosil for catalysis of the hydrolysis of urea to NH4+. The mobile phase is 20 mM KH2PO4 of pH 6.9, and the NH4+ is detected fluorimetrically, after post-column derivatization with phthalaldehyde, at 455 nm (excitation at 344 nm). This rapid method can be applied in analysis of soil, water and fertilizers. Recoveries were almost quantitative.
Ammonia, nitrogen Urea HPIC Fluorescence Sample preparation Catalysis Immobilized enzyme Post-column derivatization

"Improving The Berthelot Reaction For Determining Ammonium In Soil Extracts And Water"
Soil Sci. Soc. Am. J. 1998 Volume 62, Issue 2 Pages 473-480
E. D. Rhine, G. K. Sims*, R. L. Mulvaney, and E. J. Pratt

Abstract: Colorimetric methods based on the Berthelot reaction are used widely for quantitative determination of NH4-N in biological and environmental samples. Studies to evaluate phenol and salicylate, the most commonly used chromogenic substrates, revealed minor interferences by metallic cations, whereas up to a threefold shift in absorbance was observed with 38 diverse N-containing organic compounds. Interferences differed markedly between phenol and salicylate. The possibility of a simple correction was precluded by the fact that interferences were both positive and negative, and depended on the temperature during color development and the concentration of NH4-N. Fourteen compounds were evaluated as alternatives to phenol and salicylate, of which the Na salt of 2-phenylphenol (PPS) proved to be the most promising. Using PPS, macro- and microscale batch methods and an automated flow injection method were developed. These methods are simple, convenient, and sensitive. Using the PPS microscale method, for which the limit of detection is 0.17 mg NH4-N L-1, recovery of NH4-N added to soil extracts ranged from 98 to 104%, with a coefficient of variation of 1.4 to 2.7%. As with phenol and salicylate, precipitation of metal hydroxides was observed. Precipitation was controlled by chelation with citrate rather than ethylenediaminetetraacetic acid (EDTA), which suppressed color development by preventing monochloramine formation. Compared with Berthelot methods that use phenol or salicylate, interference by amino acids was decreased by up to 10-fold. Interference by other organic N compounds was virtually eliminated.
Nitrogen, ammonium Sample preparation Spectrophotometry Interferences

"Interfacing Of Flow Injection Pre-treatment Systems With Capillary Electrophoresis"
Trends Anal. Chem. 1998 Volume 17, Issue 1 Pages 34-41
Petr Kuban and Bo Karlberg*

Abstract: This article reviews the interfacing of flow injection analysis (FIA) with capillary electrophoresis (CE). Various sample pre-treatment procedures such as dialysis and gas diffusion can be fully automated as can the application of the electrokinetic injection principle for introduction of the treated sample into the CE system using a specially designed interface. The practical applicability of the FIA-CE technique has been demonstrated by the determination of small anions in, for instance, water, juice and milk samples. Sample throughput rates can reach 170/h and the repeatability is typically 2% (RSD).
Anions Electrophoresis Sample preparation Review Interface

"Determination Of Microamounts Of Uranium By Flow Injection Analysis"
Youkuangye 1987 Volume 6, Issue 3 Pages 33-37
Xia Buyun Liu Shaorong

Abstract: A spectrophotometric determination of uranium is presented by means of self-made Flow Injection Analysis System controlled by a microcomputer. The method uses 2-(5-bromo-2-pyridylazo)-5-diethyl-aminophenol (Br-PADAP) as chromogenic reagent of uranium at the presence of cetypyridium bromide (CPB) which makes the determination possible in aqueous solution. The common ions in the solution do not interfere the determination of uranium. The range of the determination is 0.1-2.0 mg/L (uranium). The relative standard deviation is less than 2%. About 60 samples can be analyzed per hour. The method is suitable for the analysis of microamount of uranium in waste water of uranium mills.
Uranium Spectrophotometry Computer Interferences

"Determination Of Carbonates In Waters By Online Vapor Generation FTIR"
Vib. Spectrosc. 1998 Volume 16, Issue 1 Pages 61-67
A. P&eacute;rez-Ponce, S. Garrigues and M. de la Guardia*

Abstract: An electrically heated gas-permeation unit (GPU) has been employed for the vapor-generation Fourier transform infrared (FTIR) determination of total carbonate in waters. The developed method is based on the simultaneous injection of 100 l sample and 100 l nitric acid in a two-channel manifold with a merging zone, which provides the generation of CO2 through the GPU, heated at 90°C, from which CO2 is swept by a stream of N2 to a long-path infrared gas cell. Absorbance measurements were made in the range from 2500 to 2150 cm?1 and the corresponding flow injection recordings were obtained as a function of time. The areas of these peaks are interpolated in a calibration equation obtained from aqueous standards of Na2CO3 treated in the same way as samples. The method provides a limit of detection of 4.6 ppm (expressed as mg of HCO3? L-1) and a sampling frequency of 30 h?1. Results obtained for a series of natural waters compare well with those obtained by a titrimetric reference method.
Carbonate Spectrophotometry Volatile generation Gas phase detection

"Flow Injection Immunoanalysis For The Detection Of Pesticides"
Vom Wasser 1989 Volume 73, Issue 1 Pages 345-350
Kraemer, Petra; Stoecklein, Walter; Schmid, Rolf (SFS)

Abstract: Immunochemical analysis is a promising tool for the detection of pesticides. The principle of the competitive ELISA (enzyme-linked immunosorbents assay) was transferred to the system of flow injection immunoanalysis (FIIA). The first results and the possibilities of the FIIA system are presented with the example of the detection of atrazine and aminohexylatrazine. The FIIA shows good correlation with the competitive ELISA technique, and can be used for pesticide production effluent monitoring. (SFS)
Pesticides Immunoassay

"Determination Of Phosphate In Waters By Flow Injection Analysis"
Water Air Soil Pollut. 1990 Volume 52, Issue 3-5 Pages 359-368
F. Mas, J. M. Estela and V. Cerda

Abstract: A flow injection system is described in which water (200 µL) is treated with 0.026 M molybdate ion [prepared from (NH4)6Mo7O24.4H2O] and 0.06 mM Rhodamine B solution in 0.9N-H2SO4 medium at a flow rate of 1.8 mL min-1. Baseline drift was corrected by 0.1% polyvinyl alcohol. The absorbance of the complex was measured at 586 nm. The detection limit was 12 ppb of phosphate at a signal-to-noise ratio of 3:1 and a sampling rate of 55 h-1 was achieved. The coefficient of variation in the determination of 0.02 to 0.4 ppm of phosphate was 0.13 to 0.013.
Phosphate Spectrophotometry Drift Detection limit PPB Signal to noise ratio Drift

"Automated Determination Of Nitrate In Water"
Water SA 1990 Volume 16, Issue 2 Pages 105-108
Pauer JJ; van Vliet HR; van Staden JF

Abstract: The indirect flow injection method was based on the reduction of nitrate to nitrite using online Cd reductor consisting of a 300-mm Cu tube (i.d. 0.35 mm) followed by a 100-mm column packed with Cd granules (0.3 to 0.5 mm diameter); the small i.d. of the reductor tubes limited sample dispersion, thus maintaining a high sampling frequency. Nitrite was then determined colorimetrically by the Shinn method. Precision was good (ltn1%) over nitrate concentration. range of 0.4 to 4.0 mg L-1 and recoveries were >99%. Results agreed with those obtained with a segmented flow method. At a sampling frequency of 100 per h, the carry-over was 1%. In this indirect flow injection method, water was fed via a sampling valve (2.0 mL min-1), together with 1.0 mL min-1 buffer solution, to a cadmium reduction tube consisting of a small-bore copperized cadmium column. The effluent was passed to a mixing coil with 0.16 mL min-1 of color reagent comprising aqueous sulfanilamide and N-(1-naphthyl)ethylenediamine dihydrochloride. The absorbance was measured at 520 nm. Two variations of the method were evaluated: one used the color reagent as prepared and the other used the reagent in a 1:7 dilution. Both methods showed good accuracy and precision, but the latter gave the best compromise between linearity and sensitivity. At a sampling frequency of 100 h-1, the carry-over between consecutive samples was 1%.
Nitrite Automation Buffer Valve Sensitivity Carry over Segmented flow

"Flow Injection Column Preconcentration Coupled With Atomic Absorption Spectrometry For Aluminum Determination"
Xiamen Daxue Xuebao (Ziran Kexue Ban) 1998 Volume 37, Issue 1 Pages 80-87
Yuan Dongxing, Ian L. Shuttler

Abstract: A method has been developed for the speciation anal. of Al in tea soup and water samples using an automated flow injection system coupled with an electrothermal atomic absorption spectrometer. Two pre-concentration materials, 8-quinolinol immobilized on controlled-pore glass and Amberlite XAD-2 copolymer, were investigated. Fast exchangeable Al, hydrophobic Al, and total Al can be determined by control the pre-concentration conditions.
Aluminum Spectrophotometry Preconcentration 8-Hydroxyquinoline Controlled pore glass Amberlite Column

"Biosensors For Analysis Of Pesticides In Water"
Z. Wasser Abwasser Forsch 1991 Volume 24, Issue 1 Pages 15-20
Schmid, R.D.;Gebbert, A.;Kindervater, R.;Kramer, P.M.

Abstract: A review is presented, with 34 references, with emphasis on enzyme- and antibody-based flow injection analysis.
Pesticides Sensor Enzyme Review

"Flow Injection Chemiluminescent Determination Of N-nitrosodimethylamine Using Photogenerated Tris(2,2'-bipyridyl) Ruthenium (III)"
Anal. Chim. Acta 2005 Volume 541, Issue 1-2 Pages 67-72
Tom&aacute;s P&eacute;rez-Ruiz, Carmen Mart&iacute;nez-Lozano, Virginia Tom&aacute;s and Jes&uacute;s Mart&iacute;n

Abstract: A flow injection configuration was developed and evaluated for the chemiluminescent determination of N-nitrosodimethylamine. The method is based on the on-line cleavage of the NNO bond of the nitrosamine by irradiation with ultraviolet light. The dimethylamine generated was subsequently reacted with tris(2,2'-bipyridyl) ruthenium (III), which was generated through the on-line photo-oxidation of tris(2,2'-bipyridyl) ruthenium (II) with peroxydisulfate.After selecting the best operating parameters, the emitted light showed a linear relationship with the concentration of N-nitrosodimethylamine between 1.5 and 148 ng mL-1, with a detection limit of 0.29 ng mL-1. The repeatability was 1.6% expressed as relative standard deviation (n = 10) and the reproducibility, studied on five consecutive days, was 3.2%. The sample throughput was 50 injections per hour. The method was applied to studying the recoveries of N-nitrosodimethylamine in water and different cured meat products.
N-Nitrosodimethylamine Chemiluminescence Photochemistry Optimization

"Flame Atomic Absorption Determination Of Lead Through On-line Preconcentration By Surfactant Mediated Glass Wool Retention"
Int. J. Environ. Anal. Chem. 2006 Volume 86, Issue 1-2 Pages 45-52
Christos Z. Katsaounos, Evangelos K. Paleologos, Miltiades I. Karayannis

Abstract: This work reports on the fabrication of a mini column packed with controlled pore glass and glass wool, and its application for the on-line pre-concentration of lead with the aid of an anionic surfactant (sodium dodecyl sulphate, SDS) and AAS detection. Lead reacts with SDS in a high-ionic-strength environment, and the product is retained and pre-concentrated on a high-surface-area substrate like glass wool. The intervention of controlled pore glass increases the active surface of glasswool and prevents its accumulation into a sticky mass after wetting. Washing the mini column with a methanolic solution of HNO3, causes the retained micellar face to be eluted, and consequently the lead content can be determined with AAS. A pre-concentration factor of 50 along with a signal enhancement due to the combined presence of SDS and methanol yields a detection limit of 1.5 µg/L-1. The correlation coefficient of the calibration curve is 0.999, and the linear range 5-500 µg/L-1. The method was used for the determination of lead in water and wastewater with good results.
Lead Spectrophotometry Controlled pore glass Glass microfiber Preconcentration Column Surfactant

"Kinetic Spectrophotometric Determination Of Copper By Flow Injection Analysis In Cationic Micellar Medium"
Spectrosc. Lett. 2005 Volume 38, Issue 1 Pages 13-22
A. Safavi, M. Mirzaee, M. R. Hormozi Nezhad, N. Saghir

Abstract: A sensitive catalytic kinetic method for the determination of nanogram amounts of copper by flow injection analysis (FIA) is described. The method is based on the catalytic effect of Cu(II) on the reduction of azure B by sulfide in the presence of cetyltrimethylammonium bromide (CTAB). The reaction is monitored spectrophotometrically at 647 nm. The linearity range of the calibration graph is dependent on the concentration of sulfide. The variables affecting the rate of the reaction were investigated and the optimal conditions were established. The method is simple, rapid, precise, sensitive, and widely applicable. The limit of detection is 9.2 ng mL-1, the calibration range is 50-1600 ng mL-1 of Cu(II), sampling rate is more than 60 determinations/hr, and the relative standard deviation of seven determinations of 400 ng mL-1 Cu(II) was 0.9%. The method was applied to the determination of copper in water samples.
Copper(I) Spectrophotometry Kinetic Micelle

"A Sensitive Chemiluminescence Flow Injection Procedure For Assay Of Fluoride In Waters And Humane Urine By Use Of Immobilized Reagents#"
Spectrosc. Lett. 2003 Volume 36, Issue 1-2 Pages 117-131
Zhenghua Song and Ni Zhang

Abstract: A new simple, rapid, selective and sensitive analytical procedure based on chemiluminescence (CL) detection is described for the determination of free fluoride at sub-nanogram levels by use of controlled-reagent-release technology in a flow injection system. The analytical reagents involved in the CL reaction, including luminol and periodate, were both immobilized on anion-exchange resins in a flow injection system. Through water injection luminol and periodate were eluted from the anion exchange column to generate the chemiluminescence, which was enhanced in the presence of fluoride. The increased CL intensity was linear with fluoride concentration in the range from 0.1 to 10 ng mL-1. The limit of detection was 20 pg mL-1 (3s) and the relative standard deviation (RSD) was 1.02% (n = 5) for a 1.0 ng mL-1 fluoride. At a flow rate of 2.0 mL min-1, including sampling and washing, a typical analytical procedure could be performed in 0.5 min with a RSD of less than 3.0%. The proposed method was successfully applied to determine the free fluoride in water and human urine, and the results were in good agreement with those obtained by ion chromatography.
Fluoride Chemiluminescence Method comparison Immobilized reagent

"Automated Radiochemical Procedure For Plutonium And Americium Measurement"
J. Radioanal. Nucl. Chem. 1995 Volume 197, Issue 2 Pages 211-218
A. E. Nevissi and R. S. Strebin

Abstract: A radiochemical separation method for plutonium and americium from aqueous medium has been developed using a pre-packed resin column, a peristaltic pump, and the necessary tubing and valves for flow injection technique. All the radioanalytical operations were conducted in-line. Samples made of plutonium and americium tracers in water were analyzed by this technique and counted by α spectroscopy. The results show that plutonium and americium can be measured simultaneously using this technique.
Plutonium Americium Spectroscopy Resin

"Solid Phase Retention With Reversed Elution In A SIA System With Detection By Flame Atomic Absorption Spectrometry"
Can. J. Anal. Sci. Spectrosc. 2003 Volume 48, Issue 5 Pages 320-324
COSTA Rui C. C. ; ARAUJO Alberto N. ; MONTENEGRO M. Conceicao B. S. M. ; PIMENTEL M. Fernanda ; SILVA Valdinete L.

Abstract: The development of a pre-concentration procedure based on sequential injection analysis with flame atomic absorption spectrometry (SIA/FAAS) for the determination of Mn in water samples presenting a concentration between 4.50 and 200.0 ?g L-1 is described. Mn is retained on-line on a strong cationic resin (AG 50W-X8) and eluted under stopped-flow conditions with a chelating solution. Accuracy of the results attained was assessed by comparison with electro thermal atomic absorption spectrometry providing the relationship [SIA] ?g/L = 1.00 (±0.07)*[ETAAS]?g/L - 0.3 (± 7.6) after analysis of 10 samples. Evaluation of repeatability give a relative standard deviation of 2.9 and 1.8 % after ten replicate of two samples containing 108 and 166 ?g L-1 of Mn, respectively.
Manganese Spectrophotometry

"Rapid Fabrication Of Microfluidic Devices In Poly(dimethylsiloxane) By Photocopying"
Lab on a Chip 2001 Volume 1, Issue 1 Pages 7-9
Aimin Tan, Kenneth Rodgers, John P. Murrihy, Cian O'Mathuna and Jeremy D. Glennon

Abstract: A very simple and fast method for the fabrication of poly(dimethylsiloxane) (PDMS) microfluidic devices is introduced. By using a photocopying machine to make a master on transparency instead of using lithographic equipment and photoresist, the fabrication process is greatly simplified and speeded up, requiring less than 1.5 h from design to device. Through SEM characterization, any µ-channel network with a width greater than 50 µm and a depth in the range of 8-14 µm can be made by this method. After sealing to a Pyrex glass plate with micromachined platinum electrodes, a microfluidic device was made and the device was tested in FIA mode with on-chip conductometric detection without using either high voltage or other pumping methods.
Victoria Pure Blue Conductometry Microfluidic