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

Classification: Chemometrics -> Standard additions calibration

Citations 147

"Spectrophotometric And Spectrofluorimetric Determination Of Famotidine And Ranitidine Using 1,4-benzoquinone Reagent"
Anal. Lett. 1999 Volume 32, Issue 7 Pages 1403-1419
Abdel Kader S. Ahmad; M. Abdel Kawy; M. Nebsen

Abstract: Spectrophotometric and spectrofluorimetric methods were adopted for the analysis of Famotidine and Ranitidine depending on their reaction with 1,4 Benzoquinone reagent at pH 5.2 and 5.6, respectively. The absorbances of the resulting condensation products were measured at 502 and 508 nm for Famotidine and Ranitidine, respectively. Concentrations adhering to Beers law were from 40-160 µg mL-1 for Famotidine and from 20-100 µg mL-1 for Ranitidine. Furthermore the resulting condensation products exhibited fluorescence at 665 nm when excited at 290 nm and the calibration graphs were rectilinear from 0.4-1.4 µg mL-1 for Famotidine and from 0.21 µg mL-1 for Ranitidine. Different parameters affecting these reactions were thoroughly studied. Also these methods were applied to the pharmaceutical preparations and the results were satisfactory. The validities of the methods were ascertained by the standard addition technique revealing fine results in consideration to the mean recovery percent and standard deviation. The spectrofluorimetric method was a hundred times more sensitive then the spectrophotometric method. The proposed methods were sensitive, accurate, and precise as statistically compared with the official methods of analysis of Famotidine and Ranitidine.
Pharmaceutical Plasma Human Spectrophotometry Fluorescence

"Use Of Flow Injection Sample-to-standard Addition Methods For Quantification Of Metals Leached By Selective Chemical Extraction From Sewage Sludge"
Anal. Chim. Acta 1999 Volume 381, Issue 2-3 Pages 297-305
I. Lavilla, B. Perez-Cid and C. Bendicho

Abstract: The flow injection sample-to-standard addition method (FI-SAM) proposed by Israel and Barnes and a modification of it was employed for determination of the extractable contents of chromium, lead, nickel and zinc in a sewage sludge sample obtained from an urban wastewater processing plant. The new calibration method was a modification of the one established by Israel and Barnes in which the sample was injected into a blank solution and two different standard solutions. The advantages of this modified calibration method were: (i) sample consumption was minimized in comparison with the reverse flow injection method since the sample was not used as carrier; (ii) a blank that was matrix matched to the sample was not required; (iii) a similar precision was observed in comparison with the original procedure. For studying FI-SAM calibration strategies, extractable metals obtained by using two known sequential extraction schemes (Tessier and BCR) were determined. Only fractions that required calibration with the standard addition method for metal determination were considered. FI-SAMs compensate for interference effects caused by concomitants co-extracted at each stage of the sequential extraction scheme from sewage sludge, for all metals studied except for chromium.
Chromium Lead Nickel Zinc Sludge Spectrophotometry

"Standard Addition Method In FIA. Comparison Between Different Assemblies"
Anal. Chim. Acta 1999 Volume 379, Issue 1-2 Pages 89-97
P. Campíns-Falcó, F. Bosch-Reig and F. Blasco-Gómez

Abstract: A comparison between the different proposed methods to perform the standard addition in an online way (flow injection analysis) is made. The different assemblies (reverse and conventional FIA) and the employed standards in every method are compared. Three analyzes were carried out, two of them were analyzes of samples of pH indicators (methylorange and chlorophenol red) prepared at an acid pH, while the standards were prepared at a basic pH. The third analysis was the analysis of chloride in different synthetic waters with a perfectly known composition for all the ions present in the samples. Besides a new method to perform the online standard addition is proposed, trying to reduce the consumption of reagents and sample. This new method makes use of a 6-port multiposition valve electrically actuated.
Methylorange Chlorophenol Red Chloride Water Spectrophotometry

"A Comparison Between ICP-MS And AFS Detection For Arsenic Speciation In Environmental Samples"
Talanta 2000 Volume 51, Issue 2 Pages 257-268
Jose Luis Gómez-Ariza, Daniel Sánchez-Rodas, Inmaculada Giráldez and Emilio Morales

Abstract: Performances of two atomic detectors, Inductively Coupled Plasma-Mass Spectrometry (ICP-MS) arid Atomic Fluorescence Spectrometry (AFS) have been compared for arsenic speciation in environmental samples. Instrumental couplings, based on the use of high performance liquid chromatography (HPLIC), hydride generation (HG), and the two atomic detectors were used for the speciation of arsenite, arsenate, dimethylarsinic acid and monomethylarsonic acid. Optionally, arsenobetaine was also determined using on-line ultraviolet (UV) photooxidation. The detection limits ranging from 0.1 to 0.3 µg L-1 (as As) and the precision > 10% RSD obtained with HPLC-(UV)-HG-AFS were comparable with those obtained with HPLC-(UV)-HG-ICP-MS. Both instrumental coupling were applied to the NRCC-TORT-1 and several environmental samples, such as seawater, freshwater, sediments, bivalves and bird eggs, taken from two areas with different degrees of pollution. No influence of the sample matrix was observed on the results using external calibration and standard additions met:hods, for both coupled techniques.
Arsenate ion Arsenite Arsenoβine Dimethylarsinic acid monomethylarsonic acid NRCC TORT-1 Lobster Sea Environmental River Oyster Spoonbill Fluorescence Mass spectrometry Sample preparation HPLC

"Development Of A Sequential Injection System In The Capillary Format For Determinations Of The IpaC Protein"
Anal. Chim. Acta 2000 Volume 409, Issue 1-2 Pages 3-8
D. M. Spence, E. D. Knoll, B. T. Ruotolo and J. Bjerregaard

Abstract: A sequential injection (SI) system in the capillary format is reported for protein concentration determinations employing sample volumes in the microliter to nanoliter range. By incorporating a programmable syringe pump and computer control over the selection valve and data acquisition system, the invasion plasmid antigen C (IpaC) protein concentration in a purified sample was determined. Results of flow rate, temperature, and injection studies are presented. Replicate measurements of a bovine serum albumin (BSA) standard resulted in a relative standard deviation in peak area of 3.1%. In addition, protein concentrations as low as 5 x 10^-6 M were determined in less than 3 min. This system was subsequently applied to the determination of a real IpaC sample using multiple standard additions. The error in the determination, relative to a spectrophotometric method of determination, was 7.1%. The total sample consumption for the calibration and unknown concentration determination was 60 µl.
Protein, IpaC Blood Serum

"Precision Attainable In The Determination Of Silver By Flame Atomic Absorption Spectrometry - Analysis Of Thermoelectric Silver-doped Tellurides"
Anal. Chim. Acta 2000 Volume 408, Issue 1-2 Pages 183-190
Jitka Šrámková, Stanislav Kotrlý and Pavla Jakoubková

Abstract: Effects of the presence of mineral acids and varied matrix composition were investigated to assess the reliability of flame atomic absorption spectrometric determination of Ag in milligram samples of bismuth antimony telluride monocrystals with thermoelectric properties. For optimum conditions, i.e. hydrogen ion concentration of about 1 mol l(-l) in a mixture of HNO3, HCl and tartaric acid, a linear calibration between 0.1 and 3 µg mL-1 of Ag was obtained. In order to achieve a high precision of absorbance readings, it was necessary to minimize the time delay (about 2 h for 1 mol L-1 of H+) between the preparation of solutions and the measurements. Under such conditions, a long-run reproducibility of the slope values and reliable determinations of 100-900 µg g-1 of Ag in 10^-25 mg samples were achieved with relative standard deviation of 1-3%. The 3s detection limit was estimated to be about 0.050 µg mL-1. A modified version of the standard additions technique with three steps was applied to confirm the results close to the limit of determination.
Silver Inorganic compound Spectrophotometry

"A New Sample-injection/sample-dilution System For The Flow Injection Analytical Technique"
Anal. Chim. Acta 1999 Volume 381, Issue 2-3 Pages 287-295
Milko Novic, Iñaki Berregi, Angel Ríos and Miguel Valcárcel

Abstract: A new sample-injection/sample-dilution system for the flow injection analytical technique is proposed. The system is based on two variable-speed computer-controlled peristaltic pumps and a specially designed commutator located at the merging point. One of the pumps delivers a sample and the other a carrier solution. The pumps are run in such a way that the total flow rate after the merging point remains permanently constant. The volume of the injected sample is determined by the time the sample delivering pump is on, whilst the dilution of the sample is determined by relative flow rates of sample and carrier solutions. Two additional possibilities are offered by the proposed system. Firstly, the volume of the injected sample plug can be varied in a simple way, and secondly, for the first time, the injection of a sample plug having an exactly predetermined concentration profile for the measured analyte at the merging point can be carried out. By introducing a third pump delivering a standard solution of the measured species, the system is able to perform a quantitative determination of an analyte, either by the standard addition method or by forming a calibration curve using only one standard solution.
Spectrophotometry

"Flow Injection Systems With Inductively-coupled Argon Plasma Atomic Emission Spectrometry. 2. The Generalized Standard Addition Method"
Anal. Chim. Acta 1983 Volume 145, Issue 1 Pages 169-178
E. A. G. Zagatto, A. O. Jacintho, F. J. Krug and B. F. Reis

Abstract: In multicomponent analysis by inductively-coupled argon plasma emission spectrometry, the generalized standard addition method is useful in overcoming matrix and/or spectral interferences. As this method requires many standard additions, it becomes cumbersome when done manually if many elements are to be determined. By using a flow injection system, the standard addtion manipulations required can be significantly simplified and completed within a shorter period of time with much less sample material. A flow injection system with merging zones is used to demonstrate the method for analyzes of a Ni/Cu/Zn standard and of alloys. The reproducibility of measurements of the injected sample, with or without additions of standards is always better than 99%. The results obtained compare well with those obtained by the manual procedure and also with those obtained by atomic absorption spectrometry.
Copper Nickel Zinc Alloy Industrial Spectrophotometry

"A Simple Procedure For Standard Additions In Flow Injection Analysis. Spectrophotometric Determination Of Nitrate In Plant Extracts"
Anal. Chim. Acta 1983 Volume 155, Issue 1 Pages 131-138
M. F. Giné, B. F. Reis, E. A. G. Zaatto, F. J. Krug and A. O. Jacintho

Abstract: A standard solution of NO3- is injected into water as carrier, creating a zone that undergoes continuous dispersion as it is carried through a coil. After a pre-selected time interval, Δt, a segment of the dispersed zone is introduced into a second water carrier stream and, simultaneously, the sample is injected into its carrier stream. The two established zones merge and undergo all the required physico-chemical steps before reaching the detector. The amount of standard added is determined by the value of Δt, so that several standard additions can be made by varying Δt. Application of the method is illustrated by the spectrophotometric determination of NO3- in extracts of plant leaves. Results on seven samples (12 additions per sample) agreed well with those by the corresponding manual procedure.
Nitrate Plant Sample preparation Spectrophotometry

"Determination Of Molybdenum In Steels By Flow Injection Spectrophotometry"
Anal. Chim. Acta 1984 Volume 161, Issue 1 Pages 245-255
F. J. Krug, O. Bahia and E. A. G. Zagatto

Abstract: The SCN- method was used with detection at 480 nm. The effects of Fe(III), acidity, reagent concentration. and interfering species were investigated by using the merging-zones approaching for flow injection analysis; this reduced drastically the number of standard and reagent solution required. The routine procedure developed (details given) was applied to 12 standard steels; the results obtained agreed well with those of ICP-AES and of AAS by the method of standard additions, and with the certified values. Possible interference by V, Cu, W, Co(II) and Ni(II) and means of overcoming it are discussed. Steel samples were dissolved in aqua regia; 270 solution could be analyzed in 1 h for 0.1 to 4% of Mo, with coefficient of variation <2%.
Molybdenum Alloy Spectrophotometry

"A Fast Procedure For Standard Additions In Flow Injection Analysis"
Anal. Chim. Acta 1985 Volume 171, Issue 1 Pages 337-343
M. C. U. Ara&uacute;jo, C. Pasquini, R. E. Bruns and E. A. G. Zagatto

Abstract: A method based on the concentration. vs. time profile generated by the injection of a single standard solution is described. Details of the apparatus (with a diagram) and a procedure for determining Na, Ca and K (in aqueous ethanol) by flame photometry are presented. The method can be used to correct for sudden changes in operating conditions, and it is shown that matrix modifications have little or no effect on the results. Errors of <3% were obtained when the ethanol conent was increased from 0 to 10% (v/v). The whole procedure takes 2 min.
Calcium Potassium Sodium Spectrophotometry

"Sequential Injections In Flow Systems As An Alternative To Gradient Exploitation"
Anal. Chim. Acta 1985 Volume 173, Issue 1 Pages 289-297
E. A. G. Zagatto, M. F. Gin&eacute;, E. A. N. Fernandes, B. F. Reis and F. J. Krug

Abstract: Because zone-sampling from a pronouced concentration. gradient (cf. Reis et al., Anal. Abstr., 1981, 41, 2J20; Gine et al., Ibid., 1984, 46, 7G1) is prone to imprecision due to flow fluctuations, sampling from a zone of virtually constant concentration. resulting from the merging of, e.g., three plugs of the sample solution injected simultaneously at different positions into the carrier stream ('sequential injections') has been investigated. Such a zone corresponds to one of the maxima or minima of the resultant concentration. - time profile, and the concentration. corresponding to this zone can be adjusted by varying the lengths of the mixing coils between the injection positions. An injection manifold is described for the determination of Mn in rocks by sequential-injection zone-sampling - AAS; output corresponding to a wide range of concentration. (e.g., 80 to 6000 µg g-1; up to 20 µg mL-1 injected) can be accomodated on a single recorder chart. A manifold is also described for the zone-sampling introduction of standard additions to the sample solution for the determination of Cu in ethanol by flow injection AAS.
Manganese Copper Organic compound Geological Spectrophotometry

"Heterogeneous Samples In Flow Injection Systems. 2. Standard Addition"
Anal. Chim. Acta 1985 Volume 174, Issue 1 Pages 123-132
Jeffrey J. Harrow and Jir&iacute; Janata

Abstract: The effect of undefined dispersion in flow injection analysis of heterogeneous samples can be eliminated by the method of standard additions, a significant improvement over the direct calibration method. Because flow injection analysis is a precise dilution method, the initial free volume of the sample (e.g., total volume minus haematocrit, for whole blood) must be known in order to produce accurate results for such samples. The Gran plot technique is adapted for use in flow injection analysis and it is shown that the dispersion, D, can be obtained from these experiments. In homogeneous samples, flow injection analysis with standard additions provides a means of determination which does not assume a constant dispersion and which can be used with both linear and logarithmic detectors. It is thus a robust method, which is not affected by changes in dispersion, such as those caused by bubbles or viscosity.
Potassium Whole Potentiometry

"Voltammetric Determination Of Doxorubicin In Urine By Adsorptive Preconcentration And Flow Injection Analysis"
Anal. Chim. Acta 1985 Volume 176, Issue 1 Pages 105-112
Edward N. Chaney, Jr. and Richard P. Baldwin

Abstract: A flow injection system has been applied to the earlier manual procedure (Anal. Chem., 1982, 54, 2556). The sample (6 µL) is injected into a carrier stream (0.1 mL min-1) of 0.2 M acetate buffer (pH 4.5) and passed into a detector cell equipped with a thin-layer carbon-paste working electrode (area 0.071 cm2) and a silver - AgCl reference electrode. A potential of +0.3 V is applied to the carbon-paste electrode until a stable response is obtained. Then the potential is scanned from +0.3 to +0.7 V in the differential pulse mode at 2 or 5 mV s-1. The height of the oxidation peak at +0.57 V is rectilinearly related to concentration. in the range 1 to 1000 nM-I. In order to overcome variable matrix effects in urine samples, the method of standard additions is used for quantitation. The flow injection procedure gives better discrimination against adsorbable sample components (e.g., uric acid) than the manual technique.
Doxorubicin Urine Electrode Voltammetry

"Multicomponent Determinations In Flow Injection Systems With Square Wave Voltammetric Detection Using The Kalman Filter"
Anal. Chim. Acta 1985 Volume 178, Issue 2 Pages 239-246
Caroline A. Scolari and Steven D. Brown

Abstract: Square-wave voltammetry was used in a flow injection system for detection of electroactive species. A Kalman filter was an effective aid in the separation of closely overlapping responses. A standard-additions graph for dopamine in 0.28 M H2SO4 was obtained and the peak responses were rectilinearly related to concentration. The voltammetric responses of Pb(II) and TlI in 0.9 M HNO3 on working electrodes of mercury on gold and mercury on vitreous carbon were also rectilinearly related to concentration.
Dopamine Lead Thallium Electrode Electrode Voltammetry

"Combination Of Flow Injection Techniques With Atomic Spectrometry In Agricultural And Environmental Analysis"
Anal. Chim. Acta 1986 Volume 179, Issue 1 Pages 325-340
Zhaolun Fang, Shukun Xu, Xiu Wang and Suchun Zhang

Abstract: A review is presented, with 37 references, in which the applications of the coupled techniques are discussed with emphasis on agricultural and environmental analyzes.
Arsenic Cadmium Selenium Agricultural Environmental Ion exchange Spectrophotometry Spectrophotometry Spectrophotometry Spectrophotometry Spectrophotometry

"Flow Constant-current Stripping Analysis For Antimony(III) And Antimony(V) With Gold Fiber Working Electrodes. Application To Natural Waters"
Anal. Chim. Acta 1987 Volume 202, Issue 1 Pages 123-129
Huang Huiliang, Daniel Jagner and Lars Renman

Abstract: To determine Sb(III), a sample was made 20 µM in KI (to mask Bi(III)) and 0.1 M in HCl and the solution was passed at 1 mL min-1 through a flow cell system containing a 10 µm gold-fiber working electrode, a Ag - AgCl reference electrode and a platinum counter electrode (cf. Anal. Abstr., 1987, 49, 10J160); electrolysis was carried out for 10 min at -0.4 V. Then, either 2 M HCl or 4 M HCl - 4 M CaCl2 was passed through the cell and stripping was effected at a constant current of 0.5 µA. To determine the sum of Sb(III) and Sb(V) (and hence Sb(V) by difference), electrolysis was carried out in 20 µM-KI - 4 M HCl. The method of standard additions was used for evaluation. Results obtained for Sb(V) in river water reference sample SLRS-1 were in excellent agreement with the certified value.
Antimony(3+) Antimony(5+) NRCC SLRS-1 River Amperometry Electrode

"Linear Calibration Graph Applicable To The Indirect Determination Of Sulfate"
Anal. Chim. Acta 1990 Volume 238, Issue 2 Pages 431-435
Tzyh-Chyang Tang and Hsuan-Jung Huang

Abstract: The equations derived from the equilibrium relationship between a solution of SO42- and solid PbSO4 extended the applicability of linear calibration and standard addition methods to the indirect determination of SO42- and improved the reliability of the results. The method was demonstrated by flow injection analysis.
Sulfate

"Spectrofluorimetric Determination Of Diquat By Manual And Flow Injection Methods"
Anal. Chim. Acta 1991 Volume 244, Issue 1 Pages 99-104
T. P&eacute;rez-Ruiz, C. Mart&iacute;nez-Lozano and V. Tom&aacute;s

Abstract: In the manual method, sample solution, containing 0.03 to 9 µg of diquat (I), was mixed with 2 mL of 0.5 M borax buffer (pH 8), 1 mL of 0.5% sodium dithionite and water to 10 mL and, after 5 min, the resulting stable radical of I was detected fluorimetrically at 497 nm (excitation at 428 nm). The method was also adapted for use in a flow injection procedure (diagram of apparatus and details given. The calibration graph was rectilinear from 3 to 900 and 18 to 4000 µg L-1 of I by the manual and flow injection methods, respectively; the detection limit by the manual method was 0.4 µg L-1 and coefficient of variation were 2%. The method was applied in the determination of I in commercial herbicide formulations, water, potatoes, flowers and soil (sample prep. described) and in serum and urine directly with use of a standard additions method.
Diquat Blood Serum Urine Environmental Vegetable Plant Environmental Fluorescence

"Determination Of Mitozantrone Using Phase-selective A.c. Adsorptive Stripping Voltammetry In A Flow System With Selectivity Enhancement"
Anal. Chim. Acta 1992 Volume 256, Issue 2 Pages 231-236
Juan Carlos Cortina Villar, Agustin Costa Garc&iacute;a and Paulino Tu&ntilde;on Blanco*

Abstract: Urine was diluted 1:20 to contain standard additions of 25 nM-, 50 nM- and 75 nM-mitozantrone (final concentration.), and 0.1 mL portions of these solution were injected into a carrier stream of 0.1 M HClO4 (pH 1.12; 1.5 mL min-1). The mitozantrone became adsorbed on a carbon-paste electrode (prep. described), from which it was stripped by a.c. voltammetry. For 1 µM-mitozantrone in urine, the value obtained was 0.985 µM with a coefficient of variation (n = 5) of 3.7%. A flow cell incorporating a stationary carbon paste electrode coupled with a.c. voltammetry was used. Preconcentration. and determination of the cancer chemotherapy drug mitoxanthrone (I) were achieved via a flow injection approach utilizing adsorption of the drug on the electrode, followed by medium exchange and a.c. voltammetry on the adsorbed surface. A linear response was obtained in the concentration. range 5 x 10^-9-1.5 x 10^-7 M with aqueous samples. The method was used for the determination of I in urine without any sample pretreatment; the relative standard deviation obtained was 1.1% (n = 5) with a concentration. of 1 x 10^-6M. The proposed method is more selective than other methods suggested for the determination of I in urine and plasma samples, which usually require some kind of sample pretreatment.
Mitozantrone Urine Blood Plasma Voltammetry

"Multi-site Detection In Flow Analysis. 1. Relocation Of Spectrophotometric Detector"
Anal. Chim. Acta 1992 Volume 261, Issue 1-2 Pages 59-65
E. A. G. Zagatto*, H. Bergamin Fo., S. M. B. Brienza and M. A. Z. Arruda, Ana Rita A. Nogueira, Jos&eacute; L. F. C. Lima

Abstract: Arrangements are described (with diagrams) whereby one spectrophotometric detector can be re-positioned to allow (a) parallel monitoring of several sample zones flowing through different analytical channels or (b) sequential monitoring at different sites within one channel. System (b) can be applied to procedures based on differential kinetics or requiring further processing of a previously analyzed sample. For example, a sample is mixed with all the required solution except the chromogenic reagent and the blank signal is measured at the initial position; the chromogenic reagent is then added and the detector is relocated for measurement further along the channel; the approach can also be used for methods involving standard additions or for determining a potentially interfering species before the sample reaches the site at which the analyte is determined. System (a) was applied to the determination of Fe and Al in plant digests (procedures described) by spectrophotometry at 530 nm after the addition of 1,10-phenanthroline and ascorbic acid reagents (for Fe) and Eriochrome cyanine R - ascorbic acid (for Al). System (b) was used for the sequential determination of Fe(II) (with 1,10-phenanthroline) and Fe(III) (after reduction with ascorbic acid) in natural water. Drawbacks and advantages of each system are discussed. Multi-site detection is achieved when a single detector is allowed to locate at different positions in the manifold. Relocation of the detector is accomplished by connecting its inlet and outlet tubes to strategic manifold sites. The potential and limitations of detector relocation in flow injection spectrophotometry and the influence of the dead volume of the flow cell plus accessories, manifold dimensions and commutation timing are discussed. Anal. throughput is improved with multi-site detection, but the system becomes more sensitive to effects of detector dead volume The feasibility of the approach is demonstrated in the determination of aluminum and iron in plant digests involving parallel monitoring and in the speciation of iron involving serial monitoring.
Aluminum Iron Plant Sample preparation Spectrophotometry

"Fluorimetric Determination Of Samarium(III) And Europium(III) In Neodymium Oxide By Separation With A Resin Column"
Anal. Chim. Acta 1992 Volume 266, Issue 1 Pages 67-71
Shaorong Liu* and Jian Meng, Wenhua Liu

Abstract: As only a limited amount of Nd is tolerated when the 2-thenoyltrifluoroacetone - 1,10-phenanthroline - Triton X-100 method (cf. Taketatsu and Sato, Ibid., 1979, 108, 429) is used to determine Sm or Eu, online separation of the Nd from the analytes is carried out with use of a column of P507 resin (75 mesh), which contains 2-ethylhexyl 2-ethylhexylphosphonate. The flow injection manifold used is shown diagrammatically. The optimum eluent is 0.25 M HCl - 0.5 M NaCl. By using the standard addition method, Eu can be determined without interference from Sm in up to 40-fold amount; interference by Eu in the determination of Sm is corrected for by blank subtraction and application of the standard addition method. The method was applicable in the analysis of Nd2O3 containing >0.05% of Sm and >0.005% of Eu.
Samarium Europium Inorganic compound Fluorescence

"Direct Determination Of Benzene In Gasoline By Flow Injection Fourier Transform Infrared Spectrometry"
Anal. Chim. Acta 1993 Volume 274, Issue 2 Pages 267-274
M&aacute;ximo Gallignani, Salvador Garrigues and Miguel de la Guardia

Abstract: Gasoline samples (300 µL), diluted 1:9 in hexane, were directly injected into hexane carrier (flow rate 0.28 mL min-1). Peak-height FTIR absorbance measurements were performed at 675 cm-1 and the baseline was established between 712 and 650 cm-1. The calibration graph was rectilinear from 0.02% (detection limit) to 0.8% benzene and the coefficient of variation (n = 5; 0.4% level) was ~1%. The results agreed with those obtained by offline and online standard additions methods. A rapid quality control method was developed which involved the online injection of gasoline samples (diluted 1:9 in hexane) into a carrier stream of 0.5% benzene in hexane; in this case the baseline corresponded to the max. benzene level in gasoline allowed by EC legislation. Samples with a benzene content higher than this upper limit gave positive peaks. The procedure was used to analyze a series of commercial gasoline samples and the results compared well with those of GC.
Benzene Oil Spectrophotometry

"Determination Of Picomolar Concentrations Of Titanium, Gallium And Indium In Seawater By Inductively Coupled Plasma Mass Spectrometry Following An 8-hydroxyquinoline Chelating Resin Preconcentration"
Anal. Chim. Acta 1993 Volume 282, Issue 1 Pages 63-74
Kristin J. Orians, Edward A. Boyle

Abstract: Seawater (4 l) was filtered through a polycarbonate membrane filter (0.4 µm), acidified to pH 1.5-2 with 6 M HCl, treated with 50-500 µL of 49Ti solution (50 ppb) and set aside for 2-24 h. The pH was adjusted to 4±0.3 with aqueous NH3 and the solution was pumped (4.5-5 ml/min) through a column (5 cm x 8 mm i.d.) containing 2 mL of quinolin-8-ol on a polymeric vinyl solid support. The column was washed with 3 mL of 0.02 M potassium hydrogen phthalate followed by 15 mL of water, and elution was effected with five 2 mL portions of 2.4 M HNO3. The eluate was split into two equal portions, one for direct analysis (Ti) and one for further concentration by evaporation (Ga and In, 3000-fold concentration). Analyses were performed by ICP-MS in the continuous-aspiration (0.8 ml/min) mass-scan mode (45.4-49.6 amu, Ti) or with use of FIA with a 300 µL sample loop in the peak-jump mode with standard additions (Ga and In). The detection limits for Ti, Ga and In were 0.2-0.4, 0.02 and 0.01 parts per 1012, respectively. The overall precision was 6-10% for concentrations greater than twice the detection limit and up to 20% for values near the detection limit.
Titanium Gallium Indium Sea Mass spectrometry Spectrophotometry

"Flow Injection Flame Atomic Absorption Spectrometry For Slurry Atomization. Determination Of Calcium, Magnesium, Iron, Zinc And Manganese In Vegetables"
Anal. Chim. Acta 1993 Volume 283, Issue 1 Pages 393-400
P. Vi&ntilde;as, N. Campillo, I. L&oacute;pez Garc&iacute;a and M. Hern&aacute;ndez C&oacute;rdoba*

Abstract: Washed cauliflower, bean, citrus and apple leaves were cut up, dried at 90°C, ground and calcined at 500°C for 1.5 h. The residue was ground and, for the determination of Fe, Mn and Zn with direct calibration, suspended in 10% glycerol solution containing 1% HCl, sonicated for 5 min and stirred for 10 min. The slurry was injected into a water carrier stream, which passed to the air-acetylene flame of the AAS instrument. The peak height of the transitory signal was measured. In the alternative standard addition method, the carrier was 10% glycerol/1% HCl containing added Mn(II), Fe(III) or Zn. For the determination of Ca and Mg, the ash was suspended in 1% HCl containing 1% La and 0.02% Triton X-100 and the slurry was injected into the online dilution device shown diagrammatically (Lopez Garcia et al., J. Anal. Atomic Spectrom., 1992, 7, 1291) with the same HCl-based solution as carrier. The determination limits were 12.4, 3.3 and 5.7 µg/g for Fe, Zn and Mn, respectively, and the corresponding RSD (n = 10) were 1.7, 0.9 and 0.8% at 57, 16 and 20 µg/g, respectively. In grapefruit leaves containing 0.4% Mg and 5.18% Ca, the RSD (n = 10) were 1.2 and 1.1%, respectively.
Calcium Magnesium Iron Zinc Manganese Vegetable Vegetable Leaves Plant Spectrophotometry

"Determination Of Lead By Flow Injection Inductively Coupled Plasma Mass Spectrometry Comparing Several Calibration Techniques"
Anal. Chim. Acta 1994 Volume 293, Issue 1-2 Pages 171-181
Jan Goossens, Luc Moens and Richard Dams*

Abstract: A method for the determination of Pb in wine and urine was developed using a flow injection (FI) system coupled to ICP-MS. The FI system permitted online sample dilution and online internal standardization. Three calibration procedures were compared, viz., online isotope dilution, online standard additions and external calibration. The standard-additions method was preferred with respect to accuracy, precision and flexibility. The FI system was designed so the three streams (A, B and C at 0.6 ml/min each) were merged at two consecutive T-junctions. Streams A and C carried the sample and 50 µg/l of Tl solution (internal standard), respectively. A selector valve was fitted into the third channel so that stream B carried either 0.14 M HNO3 or 100 µg/l of Pb solution in 0.14 M HNO3 (for calibration). A 70 µL portion of the merged streams was injected into the primary carrier stream (0.14 M HNO3 at 1.5 ml/min), transported to the nebulizer and analyzed by ICP-MS. The 200-210 u mass range was scanned entirely. The method was applied to undiluted wines and standard reference urine samples.
Lead Wine Urine Mass spectrometry Mass spectrometry

"Spectrophotometric Determination Of Catecholamines With Metaperiodate By Flow Injection Analysis"
Anal. Chim. Acta 1995 Volume 300, Issue 1-3 Pages 293-297
J. J. Berzas Nevado*, J. M. Lemus Gallego and P. Buitrago Laguna

Abstract: A solution (200 µL) of adrenaline or isoprenaline was injected into a 3 ml/min stream of 0.1% NaIO4 carrier, passed through a 4.3 m-long reactor and mixed with 0.05 M acetic acid/acetate buffer of pH 4.8 also flowing at 3 ml/min. The absorbance was monitored at 491 nm. The calibration graph was linear in the range 5 µM-1 mM, with a working range of 20 µM-0.2 mM. The RSD was 0.5% (n = 10) and the throughput was 120 samples/h. The method was applied to the analysis of pharmaceutical preparations. Powders were dissolved in 0.02 M buffer and liquids were diluted with the buffer prior to injection. The concentrations of the catecholamines were determined from calibration graphs or by the standard additions method.
Adrenaline Catecholamine, derivatives Isoprenaline Pharmaceutical Spectrophotometry

"Generalized Standard Addition In Flow Injection Analysis With UV-visible Photodiode Array Detection"
Anal. Chim. Acta 1995 Volume 304, Issue 2 Pages 229-236
Iben Ellegaard Bechmann*, Lars N&oslash;rgaard and Carsten Ridder

Abstract: A FIA system with spectrophotometric diode-array detection was constructed to perform generalized standard addition calibrations. The two line system allowed an undiluted sample stream to be merged with a carrier stream into which the standards were injected. The flow the passed through a knitted coil to the detector cell. The method measured the concentration of the analyte by a single injection and also provided multivariate calibration and outlier detection. The method was demonstrated by determining methyl orange and bromothymol blue in buffered solutions. Samples containing one and two analytes were analyzed as well as samples containing direct interferences. The relative errors were up to 4% for samples containing one analyte and 2-7% for samples containing two analytes. A flow injection analysis system which implements the generalized standard addition method is constructed. The FIA system, which is a model system, is furnished with a photodiode-array spectrophotometer as a detector and is a two-line system one line transports the undiluted sample, which is merged with the second line, into which the standard is injected and dispersed to obtain different amounts of added standard. The performance of the constructed flow system and the partial least-squares solution to the generalized standard addition model is investigated with indicator samples, and an outlier detection technique capable of detecting direct interferences is implemented. By introducing two chasing zones in the standard stream a two analyte calibration space will be spanned, and a generalized standard addition can be performed. Samples containing one analyte and two analytes as well as samples containing direct interferences are analyzed to test the FIA system and the outlier detection method
Bromothymol blue Methyl orange Spectrophotometry

"Electrocatalytic And Flow Injection Determination Of The Antioxidant T-butylhydroxyanisole At A Nickel Phthalocyanine Polymer Modified Electrode"
Anal. Chim. Acta 1995 Volume 305, Issue 1-3 Pages 49-56
M. A. Ruiz, M. G. Bl&aacute;zquez and J. M. Pingarr&oacute;n*

Abstract: A nickel phthalocyanine polymer film was deposited on a glassy carbon disc electrode (3 mm diameter) from a solution containing 2 mM Ni(II)-4,9,16,23-tetraaminophthalocyanine monomer and 0.5 M tetraethylammonium perchlorate in DMSO by cycling the potential between -0.2 and +0.9 V vs. SCE at 200 mV/s for the desired number of cycles. The prepared electrode was used at +0.7 V in a FIA system with Ag/AgCl/3 M KCl reference and Au counter electrodes for the determination of the antioxidant t-butylhydroxyanisole (BHA). A carrier solution (3.3 ml/min) containing 0.1 M perchloric acid and 2% methanol was used and the injection volume was 200 µL. The calibration graph was linear for 0.01-10 mg/l BHA, the detection limit was 2.7 µg/l and the RSD (n = 10) for 0.5 mg/l BHA was 1.8%. The electrode responded to sodium bisulfite, t-butylhydroxytoluene, t-butylhydroquinone, ascorbic acid and propyl gallate (PG) and relative errors of higher than 10% were obtained for interferent:BHA concentration ratios of 2:1, 1:2, 1:10, 1:4 and 1:5 respectively. The method was applied to the determination of BHA in biscuits using a standard additions calibration procedure.
3-tert-butyl-4-hydroxyanisole Food Amperometry Electrode Electrode

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

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

"Online Determination Of Vanadium By Adsorptive Stripping Voltammetry"
Anal. Chim. Acta 1995 Volume 312, Issue 1 Pages 15-25
Gillian M. Greenwaya,* and Georg Wolfbauerb

Abstract: A FIA method was developed based on the adsorption of a V-cupferron complex onto a mercury film electrode followed by cathodic stripping. The wall jet detection cell was fitted with a glassy carbon working electrode, a Ag/AgCl (3 M KCl) reference electrode and a stainless steel counter electrode. The Hg film was deposited in situ (details given) The water carrier stream was switch to the ligand stream containing 20 µM-cupferron and 0.05 M KBrO3 in 0.1 mM acetate buffer at pH 4.6 for the determination of V. Analyte solution was injected into the ligand stream and a deposition potential of +200 mV was applied to the working electrode. After 90 s the voltammogram was recorded in the differential pulse mode with a scan rate of 10 mV/s, a pulse amplitude of 50 mV and an end potential of +50 mV. All flow rates were 0.2 ml/min. The calibration graph was linear up to 3.5 µg/l of V with a detection limit of 8 ng/l. The RSD (n = 10) were 3.5%. The method was applied to the determination of V in tap water. To determine V in matrices which contain a high salt concentration, such as seawater, the measurements were carried out by anodic stripping. A deposition potential of 0 V was applied for 100 s and then the potential was scanned to +150 mV. The RSD for the determination of 1.3 µg/l V in seawater was 7% using a standard additions calibration procedure.
Vanadium Water Sea Electrode Voltammetry

"Quantitative Analysis Of Sulfadiazine Using Photochemically Induced Fluorescence Detection In Bulk Solution And In A Flow Injection System"
Anal. Chim. Acta 1995 Volume 314, Issue 1-2 Pages 45-50
J. J. Aaron,*, M. I. Acedo Valenzuela, M. Sanchez Pena, F. Salinas and M. C. Mahedero

Abstract: Room temperature photochemically-induced fluorescence methods were described for the determination of sulfadiazine (I). For the bulk solution method, portions of a standard solutions of I in 50% aqueous methanol were transferred to a 1 cm quartz cuvette and irradiated with a high-pressure mercury lamp for 2.5 min. The fluorescence intensity was then measured at 353 nm (excitation at 295 nm). The calibration graph was linear from 0.1-4.1 µg/ml of I and the detection limit was 40 ng/ml. The RSD (n = 10) was 1.7% for 2.6 µg/ml of I. For the FIA method, 300 µL of a standard solution containing 0.2-6.5 µg/ml of I was injected into a water carrier stream (4.2 ml/min) and passed through a photoreactor (length 250 cm) to the detector cell. The fluorescence intensity was measured at 352 nm (excitation at 295 nm). A linear calibration graph was obtained and the detection limit was 27 ng. The RSD (n = 10) was 2.1% for 2.1 µg/ml of I. The methods were applied to the determination of I in pharmaceutical preparations using a standard additions calibration procedure. Results agreed well with those obtained by an HPLC method.
Sulfadiazine Pharmaceutical Fluorescence

"Determination Of Codeine In Process Streams Using Flow Injection Analysis With Chemiluminescence Detection"
Anal. Chim. Acta 1996 Volume 318, Issue 3 Pages 309-317
Neil W. Barnett*, Tim A. Bowser, Richard D. Gerardi and Brent Smith

Abstract: A FIA method is described for the determination of codeine in aqueous solutions obtained during full-scale process extraction of alkaloids from Papaveraceae somniferum. The method was based on the chemiluminescence of tris(2,2'-bipyridyl)ruthenium, Ru(bipy)32+. A 20 µL volume of 4 mM Ru(bipy)32+ was injected into a 10 mM acetate carrier stream (10 ml/min) of pH 6 and transported through a solid-phase reactor consisting of lead dioxide immobilized on silica gel to produce Ru(bipy)33+. The flow was then merged with the sample stream (10 ml/min) and propelled to the detector where the chemiluminescence was measured with a photomultiplier tube. The calibration graph was linear for 0.01-1 µM-codeine, the detection limit was 5 nM and the RSD (n = 5) for 0.5 µM-codeine was 1.6%. Process solutions were diluted 105-fold with acetate buffer of pH 6 prior to analysis and a standard additions calibration procedure was used.
Codeine Industrial Chemiluminescence

"Standard Additions In Flow Injection Analysis Based On Merging Zones And Gradient Exploitation: Application To Copper Determination In Spirits"
Anal. Chim. Acta 1996 Volume 319, Issue 1-2 Pages 153-158
Edvan C. Silvaa, Mario C. U. Ara&uacute;joa, Ricardo S. Honoratoa, J. L. F. Costa Limaa, Elias Ayres Guidetti Zagattob,* and Sandra Maria Boscolo Brienzab

Abstract: A standard addition method for FIA was described which required only one standard solution and provided a series of addition levels for each injection. The dual-channel flow manifold was equipped with a sample injection loop (LS and LA, 200 µL) in each channel to allow the simultaneous injection into two water carrier streams (both at 1.8 or 3.2 ml/min). The two streams were merged and passed to the detector where the transient signal was monitored. The standard addition measurement was performed by filling loops LA and LS with water and sample solution, respectively, and recording the transient signal. Loops LA and LS were filled with standard and sample solutions, respectively, and a second transient signal was recorded. About 150 measurements were made along the tailing edge of each transient signal to provide about 150 addition levels (at 0.1 s intervals) per determination. The data was processed using a computer program written in C-language. The mathematical model accounted for dispersion and asymmetric effects relating to the merging zone process. The methodology was tested by determining K (by flame photometry) in synthetic samples and Cu (by AAS) in spirits. The RSD (n = 7) for 1-10 mg/l Cu was 5% in the presence of pronounced matrix effects. The proposed system allowed a sampling frequency of ~e;60/h.
Copper Beverage Spectrophotometry

"Automated Determination Of Lactulose In Milk Using An Enzyme Reactor And Flow Analysis With Integrated Dialysis"
Anal. Chim. Acta 1996 Volume 324, Issue 1 Pages 37-45
Michael Mayer, Meike Genrich, Wolfgang K&uuml;nnecke and Ursula Bilitewski*

Abstract: The automated FIA method was based on the enzymatic hydrolysis of lactulose to fructose and galactose followed by the separation of fructose by dialysis and its detection by fructose dehydrogenase (FDH) catalyzed oxidation with ferricyanide as electron acceptor. The manifold allowed a sample stream (0.1 ml/min) to be merged with the reaction buffer stream (0.1 ml/min) containing 185 iu/ml β-galactosidase in phosphate buffer of pH 5. The flow was propelled through a reaction coil (1.3 m x 0.8 mm i.d.) operated at 50°C and the donor channel of the dialysis cell. The acceptor channel (64 mm x 2 mm x 0.5 mm) of the dialysis cell contained stationary 2 mM potassium ferricyanide in phosphate/citrate buffer of pH 5.5. After a dialysis period of 180 s, the acceptor solution was pumped through the FDH enzyme reactor to an amperometric detector where the ferrocyanate was re-oxidized. The amperometric detector was equipped with a screen-printed Pt electrode at +385 mV vs. Pt reference. The method was applied to the analysis of milk samples using a standard-addition calibration procedure. Lactulose concentrations of up to 12.28 mM were measured and these results were confirmed by a photometric method. The sampling frequency for the proposed method was 17 samples/h.
Lactulose Milk Amperometry Electrode

"Determination Of Arsenic(III) And Arsenic(V) By Flow Injection Hydride-generation Atomic Absorption Spectrometry Via Online Reduction Of Arsenic(V) By Potassium Iodide"
Anal. Chim. Acta 1997 Volume 343, Issue 1-2 Pages 5-17
Steffen Nielsen and Elo H. Hansen

Abstract: The flow injection method for the determination of total As was based on the online reduction of As(V) to As(III) by ascorbic acid/KI reagent. Sample (100 µL) in a 4 M HCl carrier stream (9.5 ml/min) containing 0.5% ascorbic acid and 1% KI was propelled through a reaction coil (150 cm x 0.5 mm i.d.) at 140°C and a cooling coil (75 cm x 0.5 mm i.d.) at 10°C and then merged with 0.05 M NaBH4 (1.6 ml/min). The mixture was passed to a gas-liquid separator and arsine and H2 were swept to the atomizer cell (at 900°C) by an Ar carrier stream. The absorption signal for As was recorded at 193.7 nm. The same flow manifold was used for the selective detection of As(III) by using a carrier stream of 0.03 M HCl which did not contain the reducing reagents. The detection limits were 37 ng/l for total As and 111 ng/l for As(III). The RSD (n = 10) for 5 µg/l total As and As(III) were Calibration graphs were linear for 0.1-10 µg/l total As. The method was validated by analyzing certified drinking water using the multiple standard additions calibration procedure. A volume-based flow injection (FI) procedure is described for the determination and speciation of trace inorganic arsenic, As(III) and As(V), via hydride generation-atomic absorption spectrometry (HG-AAS) of As(III). The determination of total arsenic is obtained by online reduction of As(V) to As(III) by means of 0.50% (w/v) ascorbic acid and 1.0% (w/v) potassium iodide in 4 M HCl. The combined sample and reduction solution is initially heated by flowing through a knotted reactor immersed in a heated, thermostatted oil bath at 140°C, and subsequently, for cooling the reaction medium, a knotted reactor immersed in a water bath at 10°C. By using the very same volume-based FI-HG-AAS system without the heating and cooling reactors, and employing mild hydrochloric acid conditions, As(V) is not converted to arsine, thereby allowing the selective determination of As(III). The injected sample volume is 100 µl while the total sample consumption per assay is 1.33 ml, and the sampling frequency is 180 samples per hour. The detection limit (3s) for the online reduction procedure was 37 ng L-1 and at the 5.0 µg L-1, the relative standard deviation (RSD) was 1.1% (n=10) by calibrating with As(III) standards; by calibrating with As(V) standards the detection limit was 33 ng L-1 and the RSD was 1.3% (n=10). For the selective determination of As(III) the detection limit was 111 ng L-1 and the RSD was 0.7% (n=10) at 5.0 µg L-1. Both procedures are most tolerant to potential interferents. Thus, without impairing the assay, interferents such as Cu, Co, Ni and Se could, at a As(V) level of 5 µg L-1, be tolerated at a weight excess of 2000, 30000, 200 and 200 times, respectively. The assay of a certified drinking water sample by means of multiple standard addition (five levels; each three replicates) was 9.09±0.05 µg L-1 (certified value 9.38±0.71 µg l-1). 11 References
Arsenic(3+) Arsenic(5+) Water DWQI VKI-3-30494 Spectrophotometry

"Standard Additions In Flow Injection Analysis With Atomic Absorption Spectrometry"
Anal. Chim. Acta 1997 Volume 357, Issue 1-2 Pages 151-156
B. Haghighi, N. Maleki and A. Safavi*

Abstract: A standard additions method in flow injection atomic absorption analysis has been described. The proposed method was applied to the determination of calcium in synthetic samples with and without chemical interference and the results were compared with those obtained by the conventional standard additions method in atomic absorption spectrometry. The influence of parameters of the how injection system was studied. The results showed that the proposed method was independent of such parameters. The relative standard deviations within and between analyzes were found to be 1.61 and 1.81%, respectively, at the 1.5 µg mL-1 Ca level. The method was used for the determination of calcium in tap water.
Calcium Water Spectrophotometry

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

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

"Calibration Procedure For Flow Injection Flame Atomic Absorption Spectrometry With Interferents As Spectrochemical Buffers"
Anal. Chim. Acta 1998 Volume 367, Issue 1-3 Pages 101-110
Pawe

Abstract: The flow injection calibration procedure was developed to correct for interferences in flame atomic absorption spectrometry. For this purpose a sample and standard solutions were injected one after the other into the carrier stream containing some reagents known to usually produce strong interference effects. Affecting the analyte in both zones to the same extent they were able to act as spectrochem. buffers. As an example, calcium in synthetic samples containing aluminum, titanium and vanadium, and also in iron ore samples, was determined The procedure appeared to be quite effective in overcoming interferences even as strong as nearly 90%, providing anal. results with average accuracy equal to ~5%. Precision attained was 2-3 times inferior than that obtained using conventional FI calibration.
Calcium Iron Spectrophotometry

"A Time-based Flow Injection-cold Vapor-atomic Absorption Spectrometry System With Online Microwave Sample Pre-treatment For The Determination Of Inorganic And Total Mercury In Urine"
Anal. Chim. Acta 1998 Volume 369, Issue 1-2 Pages 57-67
M. Gallignani*, H. Bahsas, M. R. Brunetto, M. Burguera, J. L. Burguera and Y. Petit de Pe&ntilde;a

Abstract: A time based injection system used in conjunction with cold vapor generation atomic absorption spectrometry and microwave-aided heating oxidation with potassium persulfate has been developed for the determination of total and inorganic mercury in urine samples. Inorganic mercury is determined after reduction with SnCl2 while total mercury is determined after an online oxidation step with persulfate prior to the reduction step to elemental mercury with SnCl2. The difference between total and inorganic mercury determines the organomercury content in samples. Experimental parameters were optimized by the univariate optimization method. A linear calibration graph was obtained in the range 0.2-20 µg L-1 of Hg2+ by using injection times from 0 to 12 s of a solution of 20 µg L-1 of either inorganic or organic mercury. The detection limit based on 3s of the blank signal was 0.1 µg Hg L-1 regardless of the mercury species under evaluation. The relative standard deviations for five independent measurements were 1.5% and 1.0% for total and inorganic mercury. The recoveries of different amounts of inorganic and organic mercury added to urine samples ranged from 98.5% to 102.2% and from 97.0% to 103%, respectively. Good agreement with certified values of the total mercury containing urine reference materials were also obtained. With the proposed procedure, 20 urine samples of unexposed subjects from Merida city were measured; and the values lay in the range between 1.8 and 6.7 µg l-1. In addition, the use of a mercury standard solution as the carrier converts the flow injection manifold used in this work to an online standard addition system which permits a rapid and simple test for monitoring the mercury levels in these samples.
Mercury(II) Mercury Urine Spectrophotometry Sample preparation

"A Novel Thermal Biosensor: Evaluation For Determination Of Urea In Serum"
Anal. Chim. Acta 1998 Volume 372, Issue 3 Pages 341-348
Bjarni Bjarnason*, Peter Johansson and Gillis Johansson

Abstract: A novel thermal biosensor has been made based on heat conduction through a BiTe-thermocouple on alumina plates. The sensing element was in close thermal contact with a gold tube enzyme reactor in a flow injection system. It was successfully applied to bovine serum samples where urea could be determined from a calibration graph or by standard addition. The linear range of the system was 0.5-15 mM with a detection limit of 0.5 mM. A throughput of up to 60 samples per hour was achieved.
Urea Cow Serum Sensor Thermistor

"Estimation Of The Method Evaluation Function For The Determination Of Hydride-generating Arsenic Compounds In Urine By Flow Injection Atomic Absorption Spectrometry"
Talanta 1992 Volume 39, Issue 5 Pages 469-474
Ann J. L. M&uuml;rer*, Anne Abildtrup, Otto M. Poulsen and Jytte Molin Christensen,

Abstract: The method described by Hansen et al. (Ann. Occup. Hyg., 1991, 35, 603) was used to validate the analysis in which the samples were injected into a carrier stream and mixed with 0.5% NaBH4 solution in 0.04% NaOH. The generated arsines were carried from a gas - liquid separator by Ar to a quartz cell at 900°C and were determined at 197.3 nm. The evaluation procedure demonstrated that standard-additions calibration was necessary for acceptable performance at low concentration. (i.e., after a low-dose exposure). By this means a limit of detection of 2.9 µg L-1 was achieved. A direct flow injection atomic-absorption spectrometric (FIA-AAS) method for the assessment of inorganic As compounds and their metabolites was developed and statistically evaluated by the estimation of the method evaluation function (MEF), which provides detailed information on the analysis performance of the method. i.e., the average combined uncertainty and the magnitude of potential systematic errors. The method evaluation study demonstrated that the use of standard addition was a necessity to obtain an acceptable method performance at low concentrations. typical for low dose exposure. In contrast, the use of calibration curves resulted in a method with reduced sensitivity and high systematic error. The developed method, using standard addition, had a limit of detection (2.9 µg/mL) sufficiently low for the determination of hydride-generating As species in urine from non-exposed and low exposed persons. Organoarsenicals such as arsenobetaine and arsenocholine are not detected by this method. Hence, the contribution of these compounds derived from a diet containing seafood does not affect the monitoring of inorganic As compounds after occupational or environmental exposure. The high capacity of the FIA-AAS system (31-min per sample measured by standard addition) together with the low limit of detection makes this method suitable for biological monitoring of inorganic As exposure even though standard addition is required.
Arsenic Urine Spectrophotometry

"Interference By Volatile Nitrogen Oxides In The Determination Of Mercury By Flow Injection Cold Vapor Atomic Absorption Spectrometry"
Talanta 1993 Volume 40, Issue 5 Pages 729-735
Inge Rokkj&aelig;r, Boy Hoyer* and Nina Jensen,

Abstract: Volatile nitrogen oxides, formed as reduction products of HNO3 during sample decomposition, interfered with the flow injection AAS determination of Hg by scavenging the reducing agent, thus inhibiting Hg reduction. The interference effect was observed in the determination of Hg in sewage sludge digests and caused poor reproducibility of the mercury peak shape, the peak height being more affected than the peak area. Calibration by standard addition prevented systematic errors in the Hg determination and the interference could be remedied by purging the sample with Ar.
Mercury Sludge Spectrophotometry

"A Kinetic Dual Standard Additions Method For Simultaneous Determination Of Interfering Binary Mixtures Compensated By A Synergic Coefficient. Simultaneous Determination Of Molybdate And Tungstate"
Talanta 1996 Volume 43, Issue 3 Pages 391-396
Wang Jianhua* and He Ronghuan

Abstract: Mixtures of 0.2 µg/ml of Mo(VI) and 0.6 µg/ml of W(VI) [40 µL] were injected into a carrier stream of 0.1% starch solution at a flow rate of 2.4 ml/min. This was mixed with 10 mM KI, then with 9.7 mM H2O2. All solutions were adjusted to pH 3 (no flow rates given). The iodine-starch complex was formed in a mixing coil (30 cm x 0.5 mm i.d.) at 25°C and the flow was stopped 30 s after injection; absorbance was measured at 589 nm. Recoveries were 98.2% and 101.5% for Mo and W, respectively; corresponding RSD were 2% and 1.8% (n = 5). The method was applied to a steel sample and other simulated samples with good recoveries and slightly higher RSD (results tabulated).
Molybdenum Tungsten Alloy Spectrophotometry

"Validation Of The Determination Of Copper And Zinc In Blood Plasma And Urine By ICP-MS With Cross-flow And Direct Injection Nebulization"
Talanta 1997 Volume 44, Issue 8 Pages 1389-1396
J. Szpunar*, J. Bettmer, M. Robert, H. Chassaigne, K. Cammann, R. Lobinski and O. F. X. Donard

Abstract: Use of a Perkin-Elmer cross-flow nebulizer and a direct-injection nebulizer (Microneb 200, CETAC, Omaha, Ne, USA) were compared for the ICP-MS determination of Cu and Zn using an Elan 600 instrument (Perkin Elmer SCIEX). Plasma and urine were diluted 20- and 10-fold, respectively, in 0.05% HNO3 and 10 µg/l 89Y was added as internal standard. Isobaric interferences were eliminated for 65Cu and most of the Zn nuclides. Flow injection direct-injection nebulization was optimized for the analysis of 1-2 µL samples (parameters tabulated). Standard additions was used to eliminate matrix effects. Results using the flow injection method on reference materials agreed with the certified values.
Copper Zinc Blood Plasma Urine Mass spectrometry

"The H-point And Generalized H-point Standard Additions Methods For Flow Injection Procedures"
Talanta 1998 Volume 47, Issue 1 Pages 193-202
P. Camp&iacute;ns-Falc&oacute;*, F. Blasco G&oacute;mez and F. Bosch-Reig

Abstract: This paper establishes the fundamentals of the H-point standard additions method (HPSAM) and generalized H-point standard additions method (GHPSAM) in the flow injection technique. Two kinds of anal. signals can be employed, FIA peaks and spectra. Different anal. problems were studied: determinations of one analyte in the presence or absence of matrix effect when different blank features are present, and determination of two analytes in the presence of blank bias error affecting the development of one of them. The determination of chloride with Hg thiocyanate which presents a matrix effect, and the determinations of Ca and/or Mg with arsenazo III were examined The methods were compared with conventional data treatment and proved able to isolate the analyte signal from the global one, thus providing accurate and precise results in the determination of the above mentioned species in bottled waters. No additional experimental work is needed to apply the methods.
Chloride Calcium Magnesium Water Spectrophotometry

"Immobilization Of 8-hydroxyquinoline Onto Silicone Tubing For The Determination Of Trace Elements In Seawater Using Flow Injection ICP-MS"
Talanta 1998 Volume 47, Issue 2 Pages 439-445
S. N. Willie*, H. Tekgul and R. E. Sturgeon

Abstract: A rapid and simple online method is described for the pre-concentration of Mn, Co, Ni, Cu, Zn, Cd and Pb from seawater using 8-hydroxyquinoline immobilized onto silicone tubing (Sil-8-HQ) via the Mannich reaction. Recoveries 35-95% and limits of detection in the ppt range were obtained using a 2 m long Sil-8-HQ tube with a sample flow rate of 1.0 mL/min. A tube could be subjected to sample loading and elution cycles over 200 times. The capacity was 1.5 and 1.3 µg/cm2 for Cu and Mn, respectively. Cu, Cd, Co, Pb, Mn, Zn and Ni were determined in coastal and open ocean seawater using flow injection inductively coupled plasma mass spectrometry (FI-ICP-MS). Good agreement with certified values for the certified reference materials NASS-4 and CASS-3 was demonstrated when quantitation was undertaken by the method of additions
Manganese Cobalt Nickel Copper Zinc Cadmium Lead Sea NRCC NASS-4 NRCC NASS-3 Mass spectrometry

"Flow Injection Sample Introduction Methods For Atomic Absorption Spectrometry"
Analyst 1983 Volume 108, Issue 1283 Pages 153-158
Julian F. Tyson, John M. H. Appleton and Ahyar B. Idris

Abstract: The essential features of flow injection analysis are described and the use of flow injection methodology for sample introduction for flame atomic-absorption spectrometry is briefly reviewed. A flow injection analogue of the standard additions method has been devised and applied to the analysis of chromium in some BCS standard steels. The results showed good agreement with the certificate values. The use of a concentration gradient forming mixing chamber to provide a novel method of rapid, single-standard calibration is described and the results of preliminary experiments with magnesium show the method to be viable. The potential usefulness of both methods is critically evaluated.
Chromium Magnesium Industrial Spectrophotometry

"Determination Of Chromium In Steel By Flame Atomic Absorption Spectrometry Using A Flow Injection Standard Additions Method"
Analyst 1984 Volume 109, Issue 1 Pages 23-26
Julian F. Tyson and Ahyar B. Idris

Abstract: The determination of Cr in steel by AAS is briefly reviewed, and the basis of the flow injection standard-additions method (in which the sample solution is used as the carrier stream) is described. The effects of Fe concentration, fuel-to-oxidant ratio and dissolution procedure were investigated, and a method that requires no releasing agents and involves use of pure Cr standard solution is described. The selection of appropriate flow injection conditions by using the single well-stirred mixing chamber model for dispersion is discussed. The procedure permits a straightforward instrument-optimizing strategy to be used and can be readily adapted to the determination of more than one element in each sample.
Chromium Industrial Alloy Spectrophotometry

"Potentiometric-stripping Analysis Of Lead And Tin With A Continuous-flow System"
Analyst 1984 Volume 109, Issue 7 Pages 905-907
Saverio Mannino

Abstract: The flow cell is as used by Anderson et al. (cf. Anal. Abstr., 1983, 44, 2J123) and contains mercury-film (on vitreous carbon, prepared in situ) working and counter-electrodes and a silver - AgCl reference electrode. The sample is pumped through the cell at a constant rate and electrolysis is carried out for an appropriate time at -1.2 V. Then de-aerated ammonium citrate buffer solution (pH 4.6) containing 10 ppm of Hg(II) is passed through the cell for 30 s, the flow is stopped and the potentiometric-stripping curve is recorded. Quantitation is by the method of standard additions. The method was applied to eight samples of fruit juices or soft drinks, and results agreed with those by AAS (for Pb) or anodic-stripping voltammetry (for Sn). The proposed method can be used to determine 0.1 ppb of Sn and Pb.
Tin Lead Fruit Beverage Electrode Potentiometric stripping analysis

"Determination Of Lead In Blood Using Flow Injection And A Nebulizer Interface For Flame Atomic Absorption Spectrometry"
Analyst 1988 Volume 113, Issue 4 Pages 591-594
Olle Nygren, Carl-Axel Nilsson and Anders Gustavsson

Abstract: Blood samples (4.0 g), deproteinized by shaking with HNO3 - trichloroacetic acid followed by centrifugation, were injected into the flow system and were carried by water (2 mL min-1) via shrinkable tubing to the nebulizer interface, which consisted of a concentric glass nebulizer mounted in an aerosol chamber heated by two tapes (operated at 220 V a.c.) and connected to the flame AAS burner head. The nebulizer gas was air (1.5 l min-1), and an air - acetylene flame was used. Evaluation of the absorbance signal was improved with use of a personal computer system. The calibration graph, obtained by the standard-additions method, was rectilinear from 0.3 to 4.5 µM; the detection limit was 0.06 µM-Pb, which was a 12-fold improvement compared with that obtained with unmodified instrumentation, and the coefficient of variation was 5% at 0.5 µM-Pb in blood (n = 3). The method was used to determine Pb in blood samples from exposed workers. Results correlated well with those of an electrothermal atomization - AAS method.
Lead Blood Spectrophotometry

"Flow Injection Sample-to-standard Additions Method. Spectrophotometric Determination Of Hydrochloric Acid And Orthophosphate"
Analyst 1989 Volume 114, Issue 7 Pages 843-848
Yecheskel Israel and Ramon M. Barnes

Abstract: An equation is proposed that allows calculation of sample concentration. from two transient signals obtained from injection of sample and blank solution of matrix-matched composition. The equation was applied in the sample-to-standard additions determination of (i) HCl and (ii) phosphate in rock digests. For (i), a two-channel manifold was used with HCl as carrier (2 mL min-1), 0.2 M Na acetate - 50 mg L-1 bromocresol green - 0.002% of Triton X-100 as reagent (2.8 mL min-1) and detection at 444 nm. In general, the coefficient of variation was 1%. For (ii), a three-channel manifold was used, standard rock digests solution were used for sample and carrier (1.2 mL min-1), the reagent solution (prep. described) was molybdovanadate in dilute HNO3 (1.5 mL min-1), the diluent solution (1.2 mL min-1) was water or dilute HNO3 and detection was carried out between 410 and 450 nm. The coefficient of variation was 1%. In both instances, an autosampler was used to provide a sample throughput of 80 to 100 h-1.
Hydrogen chloride Phosphate Geological Sample preparation Spectrophotometry

"Bismuth(III) Hydride Generation, Its Separation And The Determination Of Bimuth(III) By Atomic Absorption Spectrometry Using Flow Injection"
Analyst 1990 Volume 115, Issue 5 Pages 567-569
Wing-Fat Chan and Ping-Kay Hon

Abstract: Sample (200 µL) containing Bi(III) was injected into a water stream (4.3 mL min-1) and mixed with NaBH4 solution in a reaction coil. From the gas - liquid separator comprising a PTFE membrane backed by a stainless-steel screen (10 mm x 60 mm, 200 mesh), the BiH3 diffused into a N stream (280 mL min-1) to be carried into the absorption cell. The detection limit was 0.17 ng with a rectilinear response up to 50 ppb of Bi, and a sample rate of 300 h-1 was achieved. The method was applied satisfactorily to standard gun-metal. Interference from Cu and other metals can be avoided by using the standard addition method.
Bismuth(3+) Spectrophotometry

"Flow Injection Sample-to-standard Additions Method Using Atomic Absorption Spectrometry Applicable To Slurries"
Analyst 1991 Volume 116, Issue 8 Pages 831-834
Ignacio L&oacute;pez Garc&iacute;a, Francisca Ortiz Sobejano and Manuel Hern&aacute;ndez Cordoba

Abstract: The flow injection sample-to-standard additions method of Israel and Barnes (Ibid., 1989, 114, 843) has been extended and tested on aqueous slurries of iron oxide pigments by using a standard analyte solution as carrier. The equation derived allows the calculation of analyte concentration. in a sample from only the signal from injection of the slurry and that from a standard solution The equation was applied to 0.2% slurries of Zn and 1% slurries of Cu, Mn and Cr. Results agreed well with those obtained by conventional methods.
Chromium Copper Manganese Zinc Inorganic compound Spectrophotometry

"Spectrophotometric Determination Of Lead In Tap Water With 5,10,15,20-tetra(4-N-sulfoethylpyridinium)porphyrin Using Merging Zones Flow Injection"
Analyst 1993 Volume 118, Issue 7 Pages 933-936
Jeffery A. Schneider and James F. Hornig

Abstract: Determination of lead at concentrations of ≥15 µg L-1 in aqueous samples was achieved by selective reaction with 5,10,15,20-tetra(4-N-sulfoethylpyridinium)porphyrin at pH 9.4 and 30°C in a merging zones flow injection manifold followed by detection at 480 nm after an elapsed time of 45 s. Interference by aluminum (125-fold excess), cadmium (25-fold excess), copper (25-fold excess), manganese (200-fold excess) and zinc (200-fold excess) was eliminated by the use of 1.0 mol I-1 NH3-NH4CI as a buffer/masking agent; interference by iron (10-fold excess) was eliminated by the addition of 1% v/v of acetylacetone to the reagent mixture and use of the method of standard additions for sample analysis. Recoveries from tap water samples, to which various amounts of lead had been added, ranged from 98 to 109% with a detection limit of 10 µg L-1 when iron was present in the sample matrix and 4.2 µg L-1 when it was not. Results of analyzes of tap water samples using this method were in good agreement with those obtained by electrothermal atomic absorption spectrometry. Water (150 µL) was injected into a carrier stream of water simultaneously with 75 µL of 8 µM-5,10,15,20-tetra(4-N-sulfoethylpyridinium)porphyrin in 1 M NH3/NH4Cl buffer solution of pH 9.4 containing 1% acetylacetone. The injected zones merged at a mixing tee and passed through a knitted coil reactor (3 m x 0.8 mm) before the absorbance was measured at 480 nm. The system flow rates were kept at 2 ml/min to provide a mean residence time of 45 s for all analytes and the procedure was carried out at 30°C. The carrier stream was propelled through the system by gas displacement; a diagram of the manifold is given. Recoveries of Pb were 98-109%. The detection limit was 10 µg/l of Pb when Fe was present in the sample matrix and 4.2 µg/l when it was not.
Lead Water Spectrophotometry

"Selective Continuous-flow - Stopped-flow - Continuous-flow Determination Of Sulfite In White Wines Using Immobilized Sulfite Oxidase On A Rotating Reactor"
Analyst 1994 Volume 119, Issue 9 Pages 2093-2096
Maria Olimpia Rezende and Horacio A. Mottola

Abstract: White wine was adjusted to pH 8 with 1 M NaOH and kept at room temperature for 10 min. A 5 mL portion was then diluted to 25 mL with 0.1 M phosphate buffer of pH 7.5 and the resulting solution (53 µL) was injected into a carrier stream (1.38 ml/min) of 0.1 M phosphate buffer of pH 7.5 and merged with a reagent stream (1.38 ml/min) of 0.05 M hexacyanoferrate(III). The mixture was pumped through a column packed with ascorbate oxidase immobilized on controlled-pore glass (CPG) and then into a flow-through cell, where contact was made with a rotating (840 rpm) disc containing sulfite oxidase immobilized on CPG (preparation described). The flow was stopped and the hexacyanoferrate(II) produced was detected amperometrically at a stationary Pt ring electrode at a potential of +0.38 V vs. Ag/AgCl. A diagram of the flow system used is given. The analysis could be performed without use of the ascorbate oxidase column by employing the standard additions method. The calibration graph was linear from 0.1-0.8 mM sulfite. Recoveries were quantitative. The results obtained agreed with those obtained by the official AOAC modified Monier-Williams method.
Sulfite Wine White Amperometry Electrode Electrode

"Determination Of Chloride Ions By Reaction With Mercury Thiocyanate In The Absence Of Iron(III) Using A UV-photometric, Flow Injection Method"
Analyst 1995 Volume 120, Issue 1 Pages 183-186
Joanne Cirello-Egamino and Ian D. Brindle

Abstract: The reaction between chloride ions and mercury(II) thiocyanate was studied and a method for the determination of chloride ions in water was developed. The sample (2.5-20 µL) was injected into a carrier stream (1.2 ml/min) of 0.023 and 0.035% mercury(II) thiocyanate. The sample plug passed through a knitted reactor (length 80 cm) before UV detection at 254 nm. The method was applied to tap water; the standard addition method was used for quantitation of chloride ions. The calibration graph was linear upto 40 µg/ml of chloride; the detection limit was 0.16 µg/ml. Sulfate, Mg(II) and Ca(II) ions did not interfere; bromide and iodide ions interfered at levels of 10^-100 µg/ml. The performance of the method was compared with that of the widely applied method for chloride determination in water in which Fe(III) is included as a reagent and the absorbance of the thiocyanate complex formed is measured at 450 nm. The results obtained from the two methods were statistically indistinguishable.
Chloride Water Spectrophotometry

"Continuous-flow And Flow Injection Potentiometry Of Complex-bonded Metal Ions By The Standard Additions Method"
Analyst 1995 Volume 120, Issue 6 Pages 1651-1655
Ivelin Rizov and Liliana Ilcheva

Abstract: Equations are derived that enable the standard additions method to be used in the determination of complex-bonded metal ions by continuous-flow (CF) and flow injection (FI) potentiometry. The approach allows the application of both single and multiple standard additions. The method is illustrated by the potentiometric determination of the total content of complex-bonded Ag ions in the presence of an excess of complex-forming agent (sodium thiosulfate). The RSD (n = 10) were 0.3 and 0.7% for the CF and FI systems, respectively.
Silver Potentiometry

"Sensitive Determination Of Manganese Using Flow Injection And Chemiluminescent Detection"
Analyst 1995 Volume 120, Issue 8 Pages 2119-2127
Andrew R. Bowie, Peter R. Fielden, Roger D. Lowe and Richard D. Snook

Abstract: A reagent stream (3.7 ml/min) consisting of 0.25 mM 7,7,8,8-tetracyanoquinodimethane/4 mM didodecyldim ethylammonium bromide/0.3 mM Eosin Y and a stream (3.7 ml/min) of 0.01 M NaOH were mixed in a 2 m coil. The mixed stream was transferred to a spiral flow cell where it was mixed with an aqueous carrier stream (3.7 ml/min) into which the sample (90 µL) had been injected. The chemiluminescence intensity produced was measured. Three flow regulators (each consisting of 1 m of coiled tubing) were employed on each of the stream lines to act as pulse dampeners. Diagrams of the manifold and spiral flow cell used are given. The calibration graph was linear from 0-100 ppb of Mn, the detection limit was 4.5 ppb and the RSD (n = 20) was 4.9-5.3%. Interference from Fe was masked with desferrioxamine and the standard additions method was used for quantification of Mn. The method was applied to the analysis of Mn in potable water. The results obtained showed reasonable agreement with those obtained by electrothermal AAS.
Manganese Water Chemiluminescence

"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 Water Spectrophotometry

"A Variable Dispersion Flow Injection Manifold For Calibration And Sample Dilution In Flame Atomic Absorption Spectrometry"
J. Anal. At. Spectrom. 1986 Volume 1, Issue 4 Pages 273-276
Julian F. Tyson, James R. Mariara and John M. H. Appleton

Abstract: The manifold comprised six tubes of different dimensions (6 cm x 0.7 mm, and 18, 26, 60, 131 and 229 cm x 1.1 mm) in parallel, with a six-way switching valve at each common end. These tubes gave measured dilution factors (dispersion coefficient) of 5.93, 8.67, 10.35, 14.87, 25.99 and 38.84, respectively, which, when applied to the concentration. (5 ppm) of standard Mg solution (12.5 µL of which was passed down each tube), permitted a calibration graph to be established. When solution containing 6, 12.5, 12.5 and 35 ppm of Mg were passed down the tubes that gave dilution factors of 14.87, 14.87, 25.99 and 38.84, respectively, the concentration. found from the calibration graph were 6.1, 12.5, 12.4 and 33.8 ppm. Calibration with solution containing Ca, Cr or Ni gave 98 to 102% recovery of 75, 180 and 180 ppm of the respective metals from at least one of the tubes. The dilution factors were independent of concentration, but their uncertainty did render the over-all precision inferior to that for conventional calibration.
Chromium Copper Magnesium Nickel Spectrophotometry

"Determination Of Copper In Concentrated Matrices By Flow Injection With Inductively Coupled Plasma Atomic Emission Spectrometry"
J. Anal. At. Spectrom. 1988 Volume 3, Issue 2 Pages 375-380
David E. Davey and Georg J. H. Metz

Abstract: Flow injection ICP-AES has been applied to determine Cu in solution containing sulfate compounds, e.g., H2SO4, Na2SO4, K2SO4, MgSO4 and ZnSO4, of which ZnSO4 has a particularly strong effect on Cu emission. Samples were mixed with carrier solution in a four-way rotary valve fitted with a 150 µL sample loop and placed 20 cm from the Meinhard nebulizer. The determination of Cu at its 327.4-nm line was achieved by direct calibration with matrix-matched standard solution and by standard additions. The effects of major matrix elements and of carrier stream flow rate were studied. At a flow rate of 10 mL min-1, the coefficient of variation was 2 to 6% and noise levels were reduced relative to those at lower flow rates. The technique was applied to determine Cu in Burt filtrates from a zinc plant; recoveries at 10 mL min-1 were 100 to 103%. The method was compared with a xanthate procedure and was found to be more rapid and precise.
Copper Process liquor Spectrophotometry

"Determination Of Germanium By Hydride Generation Inductively Coupled Plasma Atomic Emission Spectrometry Combined With Flow Injection"
J. Anal. At. Spectrom. 1988 Volume 3, Issue 4 Pages 579-582
Fumio Nakata, Hiroshi Sunahara, Hiroyoshi Fujimoto, Manabu Yamamoto and Takahiro Kumamaru

Abstract: The sample (20 to 40 mg) of single-crystal gallium arsenide was dissolved in HNO3 and the solution was diluted with water to 25 mL. A 1 mL aliquot was analyzed by a system (illustrated) consisting of a PTFE flow injection manifold by which the sample is mixed with sodium phosphate buffer (pH 6.5), NaBH4 solution and Ar (carrier gas), and a gas - liquid separator, constructed from micro-porous PTFE (cf. Yamamoto et al., Anal. Chem., 1987, 59, 2446), that delivers the generated hydrides directly into the sample introduction tube of the ICP torch (central orifice 0.6 mm i.d.) for determination of Ge at 265.18 nm. The calibration graph was rectilinear for 1 ng mL-1 to 10 µg mL-1 of Ge; the detection limit was 0.4 ng mL-1. By using the method of standard additions, recovery of 4 ng mL-1 of Ge from non-doped, Zn-doped and Si-doped gallium arsenide was satisfactory, but no indigenous Ge was detected. The method was also applied in the analysis of poly(ethylene terephthalate) (sample prep. described); recoveries were 90 to 120%, and 2.5 to 3.1 ng mL-1 of Ge was detected, which is better than the detection limit (5 ng mL-1) of the official method. The sample throughput was ~150 h-1.
Germanium Inorganic compound Polymer Spectrophotometry

"Flow Injection Calibration Of Inductively Coupled Plasma Atomic Emission Spectrometry Using The Generalized Standard Additions Method"
J. Anal. At. Spectrom. 1988 Volume 3, Issue 5 Pages 673-678
Maria Fernanda Gin&eacute;, Francisco Jos&eacute; Krug, Henrique Bergamin Filho, Boaventura Freire dos Reis, Elias Ayres Guidetti Zagatto and Roy Edward Bruns

Abstract: The generalized standard-additions method, employing least squares regression, was applied to obtain the calibration matrix for multi-element analysis by ICP-AES. The method is based on response variations following known additions of interfering and test elements. As a number of additions are required, a flow injection system that permits high sampling rates and low consumption of sample is used. The zone sampling approach is applied as it allows selection of regions with different mean concentration. The flow injection apparatus is coupled to an ICP-AES instrument, the operating parameters of which are adjusted to minimize inter-element effects. The method was applied in the analysis of rock reference materials and results agreed well with certified values. The reproducibility of the calibration matrix was >99.5%.
Trace elements Geological Environmental Spectrophotometry

"Design And Optimization Of A Flow Injection Hydride Generator And Its Use For Automated Standard Additions"
J. Anal. At. Spectrom. 1990 Volume 5, Issue 8 Pages 675-679
raham D. Marshall and Jacobus F. van Staden

Abstract: The flow injection hydride generator is described and depicted schematically. The sample is injected into an acidic carrier stream which is subsequently merged with the reductant. The apparatus allows rapid analysis, ease of automation and simple inline handling of interferences. To determine, e.g., As, the sample was injected into a stream of 4.8 M HCl (1.8 mL min-1) and mixed with a stream of aqueous NaOH (10 g l-1) containing 1.0% of NaBH4 in a reaction tube (50 cm x 1.5 mm). An Ar stream (35 mL min-1) was used to strip the AsH3 from the solution in a separator with a cotton gauze membrane and the As was determined by AAS at 193.7 nm. Calibration graphs were rectilinear for 40 ng to 0.5 µg mL-1 of As with coefficient of variation 2.9% (n = 10); the detection limit was 8 ng mL-1 of As. The detection limits of Bi, Sb, Se and Te were 2, 10, 6 and 3 ng mL-1, respectively, while those of Ge, Pb and Sn were similar to flame AAS values.
Arsenic Germanium Lead Tin Spectrophotometry

"Direct Determination Of Copper And Iron In Edible Oils Using Flow Injection Flame Atomic Absorption Spectrometry"
J. Anal. At. Spectrom. 1991 Volume 6, Issue 7 Pages 581-584
Vincente Carbonell, A. R. Maur&iacute;, Amparo Salvador and Miguel de la Guardia

Abstract: A procedure is described that allows the determination of Cu and Fe in oil without prior treatment or dilution. Samples are continuously aspirated (1 mL min-1) into the flame using a single manifold and organic standard solutions of Cu and Fe in oil are injected via a flow injector loop into the flow. The variation in the absorbance values from the baseline is measured and the direct standard additions method used to determine Cu and oil content of samples. The instrumental and flame conditions are optimized to obtain the best sensitivity and repeatability with direct introduction of oil samples.
Copper Iron Oil Spectrophotometry

"Online Enrichment And Determination Of Trace Sulfur In High-purity Iron Samples By Flow Injection And Inductively Coupled Plasma Atomic-emission Spectrometry"
J. Anal. At. Spectrom. 1992 Volume 7, Issue 4 Pages 661-665
Kei Yamada, Cameron W. McLeod, Osamu Kujirai and Haruno Okochi

Abstract: The sample was dissolved in HNO3 - HCl (1:1) and the solution was passed through a column of activated acidic alumina 90 to enrich the SO42- (eluted with aqueous 2 mM NH3) and remove the Fe. The standard-addition method was used. The limit of detection was 0.3 ppm. Flow injection systems were combined with an inductively coupled plasma atomic emission spectrometer for the development of online enrichment and determination of trace amounts of S in high-purity iron samples (obtained as Certified Reference Materials from the Iron and Steel Institute of Japan). An alumina microcolumn was used for the enrichment of sulfate and the removal of Fe. The properties of several types of alumina were compared. The effects of Fe, diverse elements and acids on the adsorption of sulfate were investigated. The detection limit (3s) of S in high-purity iron is 0.3 µg g-1. A standard additions method and 2 online standard addition methods were used for the determination The possibility of S vaporization at the trace amt. level is evaluated.
Sulfur High purity Sample preparation Spectrophotometry

"Multipurpose Flow Injection System. 1. Programmable Dilutions And Standard Additions For Plant Digests Analysis By Inductively Coupled Plasma Atomic-emission Spectrometry"
J. Anal. At. Spectrom. 1992 Volume 7, Issue 6 Pages 865-868
Boaventura Freire dos Reis, Maria Fernanda Gin&eacute;, Francisco Jos&eacute; Krug and Henrique Bergamin Filho

Abstract: Combinations of the injector commutator and solenoid valves provided a simple way of achieving different flow injection configurations for standard additions and dilutions. Results for Ca, Mn and Zn in three vegetable samples agreed well with reported values. A flexible flow injection system to perform multipurpose functions related to sample handling is proposed. The flow network consists of a sliding injector commutator, solenoid valves, and other minor components. A dedicated microcomputer controls these devices, facilitating the definition of different flow configurations. Merging zones, zone sampling, intermittent flow, sequential injections, zone trapping, and stopped-flow are possible. Online programmed dilutions and standard additions for simultaneous determinations on plant digests by inductively coupled plasma atomic emission spectrometry were chosen to demonstrate some features of the system. Sample dilutions were accomplished by confluence at different points along the analysis path through a proper programming of the solenoid valves. Standard additions were performed by merging the sample zone with an aliquot delivered from a trapped standard zone in a modified version of the zone sampling process. To minimize matrix effects from the nitric-perchloric acid digests, a sequential dilution procedure is proposed for the major elements and standard additions for the minor constituents. No other standardization procedure was necessary and results were calculated by using the least squares regression method. Results obtained with the proposed procedure compared well with the reported values for plant reference materials.
Calcium Manganese Zinc Vegetable Sample preparation Spectrophotometry

"Sensitive Method For Determination Of Lead By Potassium Dichromate-lactic Acid Hydride Generation Inductively Coupled Plasma Atomic-emission Spectrometry"
J. Anal. At. Spectrom. 1993 Volume 8, Issue 6 Pages 821-825
M. C. Vald&eacute;s-Hevia y Temprano, M. R. Fern&aacute;ndez de la Campa and Alfredo Sanz-Medel

Abstract: For the continuous-flow determination of Pb as PbH4 by hydride-generation ICP-AES, generation with use of 0.3% K2Cr2O7/3% lactic acid and 5% NaBH4 in 0.1% NaOH as reagents was chosen and optimization of the detection limit was studied. With use of a r.f. forward power of 700 W and detection at 220.353 nm, a detection limit of 2 ng/ml of Pb was obtained with an RSD of 1.3% at 50 ng/ml. The cited method was applied to the determination of Pb in soft-drinks, sediment and lichen reference materials. Soft drinks, containing 11-66 ng/ml, were injected directly and Pb was determined with the aid of a standard-additions procedure.
Lead Environmental Soft drink Plant Spectrophotometry

"Use Of Flow Injection Cold Vapor Generation And Preconcentration On Coated Graphite Tubes For The Determination Of Cadmium In Seawater By Electrothermal Atomic Absorption Spectrometry"
J. Anal. At. Spectrom. 1996 Volume 11, Issue 11 Pages 1081-1086
Pilar Bermejo-Barrera, Jorge Moreda-Pi&ntilde;eiro, Antonio Moreda-Pi&ntilde;eiro and Adela Bermejo-Barrera

Abstract: Seawater was collected in 100 mL glass bottles and acidified with 0.1 mL 16 M HNO3 to prevent adsorption of Cd(II) on the glass walls. Portions (9 ml) were treated with HCl and gallium(III) nitrate to give final concentrations of 0.25 M and 0.5 µg/ml of Ga in 10 mL. This solution (0.5 ml) was injected into the carrier, 0.25 M HCl, which was pumped into the generator at 9 ml/min for 30 s, together with 2% NaBH4 in 0.5% NaOH, pumped at 5 ml/min for 30 s. The CdH2 generated was transferred through a quartz tube (2 cm x 0.5 mm i.d.) to the integral platform of a pyrolytic graphite furnace tube with a stream of Ar (150 ml/min) for 30 s. The furnace tube had been coated with Ir (details given); at 20°C the CdH2 was rapidly adsorbed to the coating. The Cd was then atomized at 1300°C for 4 s without gas flow and measured at 228.8 nm. The Ga(III) gave the best catalytic yield of CdH2 of several cations tried. Calibration graphs (no ranges given) in the carrier solution or prepared from synthetic or real seawater by standard additions had similar slopes, indicating no matrix interference; the detection limit was 4 ng/l. At 0.25-0.5 ng/l the in batch RSD were 0.2-0.4% (n = 11). The method was applied to six seawater samples (0.04-1.2 µg/1) giving RSD of 1.6-4.2% (n = 4).
Cadmium Sea Spectrophotometry

"Determination Of Total Mercury In Sediments By Microwave-assisted Digestion - Flow Injection Inductively Coupled Plasma Mass Spectrometry"
J. Anal. At. Spectrom. 1997 Volume 12, Issue 1 Pages 53-56
&Aacute;GNES WOLLER, HERV&Eacute; GARRAUD, FABIENNE MARTIN, OLIVIER F. X. DONARD and P&Eacute;TER FODOR

Abstract: Dry sediment (0.25 g) was digested in an open vessel with 8 mL of HNO3 and again after cooling for 5 min and addition of 2 mL of 30% H2O2, in both instances at 20 W for 5 min. The digest was then diluted with water to the required concentration range of Hg; 5 mL portions of the analytical solution contained 0.1% of Triton X-100, 0.1% of EDTA, 0.1% (v/v) of aqueous NH3, 20 ng/ml of Tl (internal standard), and standard additions of 0-40 ng of Hg. The analysis was based on the ICP-MS detection of 202Hg, while 200Hg was detected for confirmation. The detection limit was 1 ng/g. Recoveries were 95-105%, and results for the reference materials PACS-1, IAEA-356 and S19 agreed well with the certified values.
Mercury Environmental NRCC PACS-1 IAEA 356 IAEA S19 Mass spectrometry Sample preparation

"Determination Of Cadmium In Aqueous Media By Flow Injection Cold Vapor Atomic Absorption Spectrometry. Application To Natural Water Samples"
J. Anal. At. Spectrom. 1998 Volume 13, Issue 4 Pages 295-300
Mar&iacute;a Liva Garrido, Riansares Mu&ntilde;oz-olivas and Carmen C&aacute;mara

Abstract: A simple, sensitive, and rapid flow injection system for Cd cold vapor generation coupled to atomic absorption spectrometry (FI-CV-AAS) was developed. A vesicular medium of didodecyldimethylammonium bromide (DDAM) was investigated in order to understand the possible mechanisms occurring in Cd cold vapor generation and the influence of this surfactant as a catalyst. Similar experiments in an aqueous medium were carried out with optimization of the physical and chemical parameters. Identical analysis characteristics such as linearity and precision, and similar detection limits (0.15 and 0.05 µg/L for DDAB and aqueous media, respectively), were found for both reaction media; hence, the use of surfactants was not necessary for Cd cold vapor generation. Validation of the method was carried out by determining the Cd content in several certified waters. The method was applied to the anal. of some natural waters by the standard additions calibration method.
Cadmium Environmental Spectrophotometry

"Standard Addition Method In Flow Injection Analysis With Inductively Coupled Plasma Emission Spectrometry"
Anal. Chem. 1984 Volume 56, Issue 7 Pages 1188-1192
Yecheskel Israell and Ramon M. Barnes

Abstract: A rapid 'inverse' flow injection analysis method was developed, based on measurement of the two transient signals relating to the concentration. of the analyte in the continuously flowing sample and the added standard under identical conditions in ICP-AES A simple mathematical model was derived and applied to the determination of Si in aqueous solution in the range 0.4 to 400 ppm; recoveries were 96.9 to 104.6%. The optimum operating conditions for the ICP-AES, determined by simplex optimization, are tabulated. The standard-addition method equation derived and signal-to-noise ratios are discussed with reference to the experimental parameters. The recoveries of Si decreased with increasing viscosity of the sample solution
Silicon Industrial Spectrophotometry

"Simultaneous Flame Photometric Determination Of Lithium, Sodium, Potassium, And Calcium By Flow Injection Analysis With Gradient Scanning Standard Addition"
Anal. Chem. 1985 Volume 57, Issue 7 Pages 1457-1461
Zhaolun Fang, Joel M. Harris, Jaromir Ruzicka, and Elo H. Hansen

Abstract: A fast-scanning monochromator coupled to a digital oscilloscope was used to obtain analyte emission spectra (from 350 to 800 nm) from an air - acetylene flame. The method was applied to the determination of Na, K and Ca in 1 M ammonium acetate extracts of soil and in tap-water, the coefficient of variation for the metals being 3.9, 3.2 and 4.6%, respectively (n = 11). Addition of Li as an internal standard gave an improvement to 2.5% for Na but did not affect the coefficient of variation for the others. The results agreed closely with those obtained by a conventional flame-photometric method.
Sodium Potassium Calcium Environmental Water Spectrophotometry

"Online Standard Additions With Direct Injection Nebulization For Inductively Coupled Plasma Mass Spectrometry"
Anal. Chem. 1991 Volume 63, Issue 15 Pages 1626-1631
Daniel R. Wiederin, Ronald E. Smyczek, and R. S. Houk

Abstract: A flow injection system is described (with diagram) for online standard additions in trace element determination by the cited technique. Carrier solution is passed through Tefzel tubing (0.5 mm i.d.) to a PEEK tee (0.25 mm i.d.) connected to two high-pressure metal-free flow injection valves via Tefzel tubing. Sample solution are injected via one valve and standard solution are sequentially injected via the second valve. The valves are connected to a second PEEK tee via fused-silica transfer lines (50 µm i.d.). Solutions are passed from the second PEEK tee to the nebulizer through a fused-silica tube. To minimize salt deposition, the direct injection nebulizer tube diameter was reduced to 1 mm, and the tip was modified to accommodate the reduction and the make-up gas flow rate was increased to 0.4 l min-1. The system was applied in the determination of 9 elements in NIST SRM 2670 Toxic Metals in Freeze-Dried Urine. Correction for instrumental drift, viscosity and background effects are discussed.
Trace elements NIST 2670 Urine Mass spectrometry

"Online Standard Addition Method With ICP-MS Using Flow Injection"
Anal. Chem. 1995 Volume 67, Issue 9 Pages 1553-1557
Diane Beauchemin

Abstract: A Perkin-Elmer SCIEX ELAN 500 instrument fitted with a mass flow controller, a PlasmaTherm torch and a translational stage for the torch box was used in conjunction with a single-line flow injection manifold in which a peristaltic pump controlled the flow of carrier to a sample injection valve connected to the Meinhard nebulizer by PTFE tubing. Operating conditions used to determine trace metals in 1% HNO3/0.01 M K medium and in standard seawater are tabulated. Initially, 1% HNO3 was used as carrier, into which a multi-element or single-element standard was injected. After rinsing of the loop, the sample was injected. The standard was then used as carrier for a further injection of sample. To minimize rinsing time, for the next run the sample was injected first into the standard carrier and then into the blank carrier, after which the standard was injected into the blank carrier. Sample consumption was reduced, a matrix-matched blank was not necessary, and sensitivity was close to that with continuous sample nebulization. However, precision was poorer than that of peak height calibration. The method was used to determine Mo in standard seawater. A single-line flow injection manifold was used to perform the standard addition method online with ICPMS. The proposed approach requires injection of the sample into two different carriers (i.e., a blank and a standard with a greater concentration than that of the sample), as well as injection of the standard in the blank carrier. The method takes into account the change in sensitivity induced by the sample upon its injection into the standard carrier. In the best conditions, one replicate multielemental analysis by the online standard addition method was accomplished in 200 s (using 100 mL injections). Furthermore, the setup induced only limited dispersion (i.e., the dispersion coefficient was between 1.2 and 2) and therefore provided sensitivity similar to that expected from direct continuous nebulization of the sample. Although precision was poorer than that which is typical of, for instance, external calibration, the proposed method adequately compensated for the effect of a 0.01 M K matrix, allowing the accurate determination of V, Co, Ni, Cu, Zn, Mo, Cd, Sb, and Pb in this matrix. The method was also successfully applied to the direct determination of Mo in seawater. Copyright 1995, American Chemical Society.
Metals, heavy Antimony Cadmium Cobalt Copper Lead Molybdenum Nickel Vanadium Zinc Sea Mass spectrometry

"Comparison Of Continuous-flow And Flow Injection Analytical Techniques For The Photometric Determination Of Traces Of Aluminum In Water And Soil Samples"
Fresenius J. Anal. Chem. 1984 Volume 317, Issue 3-4 Pages 422-426
D. Z&ouml;ltzer und G. Schwedt

Abstract: For the continuous-flow determination of Al, air is added to the stream of test solution from a multi-channel pumping system, then ascorbic acid is added to the sample - air mixture, and, after passage of the resulting mixture through a mixing coil, Chrome Azurol S (C. I. Mordant Blue 29) in aqueous 50% ethanol and acetate buffer are added. After passage through a second mixing coil, the mixture enters a debubbler, and Al is determined in the air-free solution at 546 nm. For flow injection analysis, the sample is injected into a stream of carrier (H2O), ascorbic acid is added, and after passage through a mixing coil, Chrome Azurol S solution in acetate buffer is added. After passage through a second mixing coil, the flowing solution is examined spectrophotometrically at 546 nm. The latter method gives the more symmetrical signals, and its sampling rate and reproducibility are better. The detection limit is ~10 ng mL-1 of Al. The tubing used in either method must be of PTFE (as glass adsorbs Al). In the analysis of soil solution and water, the standard-addition technique must be used.
Aluminum Environmental Environmental Spectrophotometry

"Determination Of Aluminum In Hemodialysis Fluids By A Flow Injection System With Preconcentration On A Synthetic Chelate-forming Resin And Flame Atomic Absorption Spectrophotometry"
Fresenius J. Anal. Chem. 1986 Volume 325, Issue 3 Pages 300-302
Pedro Hernandez, Lucas Hernandez and Jose Losada

Abstract: In a single-line flow injection system, a serum sample (from uraemic patients) containing 25 to 200 ng of Al is injected into a flow of buffer solution (aqueous 0.5 M NH3 - ammonium acetate, pH 8) and passed through a micro-column (2 cm x 2 mm) of anion-exchange resin modified with Chrome Azurol S (C. I. Mordant Blue 29), giving 100% retention of Al at a flow rate <2 mL min-1. The Al is eluted with 100 µL of 1 M NaOH at 1.5 mL min-1 into the N2O - acetylene flame of the spectrometer. Calibration is rectilinear in the range 25 to 200 µg l-1. The detection limit is 15 µg L-1 (<10 µg L-1 with standard additions) and the coefficient of variation is 0.88 to 1.48%.
Aluminum Blood Serum Clinical analysis Spectrophotometry

"New Flow Injection Analysis Methods For The Determination Of Ions. 1. Halides"
Fresenius J. Anal. Chem. 1988 Volume 330, Issue 6 Pages 489-493
F. Frenzel, N. Almhofer, G. Citroni und W. Hager

Abstract: The flow injection system consists of an HPLC pump, a sample injection point and a measuring cell coupled to a potentiostat and a pH meter interfaced with a computer for amperometric recording. The cell is a Plexiglas cylinder with bores for inflow and outflow and Ag - AgCl measuring and reference electrodes; the measuring chamber volume is ~50 mm3. The carrier stream (2 mL min-1) is 1 mM NaClO4 - 1 mM HClO4. A single measurement takes ~2 min including pause. Results for determination of 3 to 450 mg L-1 of Cl- in synthetic and real water samples agree well with potentiometric measurements and the average coefficient of variation is 1.5%. Selectivity coefficient are quoted for the Cl- - I-, Cl- - Br-, Cl- - CN- and Cl- - S2- ion pairs and instructions are given for rectilinear and non-rectilinear calibration in the presence of ion matrix effects, by the method of standard addition and dilution (or precipitation with AgNO3).
Halides Chloride Environmental Amperometry Potentiometry Electrode

"Use Of Flow Injection Analysis Based On Iodometry For Automation Of Dissolved Oxygen (Winkler Method) And Chemical Oxygen Demand (dichromate Method) Determinations"
Fresenius J. Anal. Chem. 1988 Volume 332, Issue 7 Pages 750-755
M. Novic, B. Pihlar and M. Dular

Abstract: In the modified Winkler method, water (300 ml) was mixed with 1 mL of each of the precipitation solution and 1 mL of concentrated H2SO4 and, after 30 min, an aliquot was injected into a stream of water (0.56 mL min-1) and mixed with 0.4 M KI (0.56 mL min-1). After passing through a PTFE reaction tube (50 cm x 0.5 mm), the I3- in solution was determined amperometrically in a wall-jet cell at a vitreous-carbon electrode at -200 mV vs. Ag - AgCl. Dissolved O was determined by the standard-additions method with use of KIO3 as standard. Calibration graphs were rectilinear for up to 30 mg L-1 of dissolved O and the detection limit was 5 µg l-1. Results agreed with those obtained with a WTW OXI 91 oxymeter. The apparatus could also be modified for use in the determination of COD by oxidation of organic compounds with K2Cr2O7 in H2SO4 and reaction of the excess of K2Cr2O7 with KI producing I3- which was determined amperometrically as above.
Chemical oxygen demand Oxygen Environmental Amperometry Electrode Electrode

"Direct Determination Of Copper And Iodine In Milk And Milk Powder In Alkaline Solution By Flow Injection Inductively Coupled Plasma Mass Spectrometry"
Fresenius J. Anal. Chem. 1996 Volume 354, Issue 3 Pages 323-326
S. St&uuml;rup and Arne B&uuml;chert

Abstract: Milk powder (0.2 g) was dissolved in 50 mL 0.05 M KOH/0.07 M tetramethylammonium hydroxide, or 0.5 mL raw milk was diluted with 9.5 mL of the alkaline mixture. Each sample was spiked twice with 5 and 10 µg/l I2 and Cu for standard-addition calibration to overcome matrix effects. Analysis was performed using a FIA system with a 500 µL injection loop, the alkaline mixture as carrier and ICP-MS detection. The analyte masses were monitored at m/z 63 and 127. The measurement time was 70 s/injection, which resulted in a high sample throughput. The detection limits were 0.45 and 0.94 µg/l for I2 and Cu, respectively. The method was applied to monitoring over 100 milk samples.
Copper Iodine Milk Powder Mass spectrometry

"Atomic Absorption Spectrometric Determination Of Mercury In Soil Standard Reference Material Following Microwave Sample Pretreatment"
Microchim. Acta 1995 Volume 119, Issue 1-2 Pages 137-146
Ewa Bulska, Wolfgang Kandler, Piotr Paslstrokawski and Adam Hulanicki

Abstract: Various decomposition methods were compared for the determination of Hg in soil reference material by ETAAS and flow injection cold vapor AAS. Open and closed vessel microwave digestion using 1 M HCl, concentrated HNO3 or aqua regia and digestion under reflux according to the German standard method were used (details given). The temperature program for ETAAS is tabulated; Hg was determined at 253.7 nm with background correction and use of Pd as modifier (details given). For cold vapor AAS, samples were reduced with SnCl2 or NaBH4 and Hg vapors were stripped with Ar and transferred to the absorption cell of the Perkin Elmer FIAS-100 or FIMS systems used. ETAAS was suitable for soil containing 6.25 µg/g Hg. For open microwave digestion with HCl recoveries were 89-98% and RSD were 1-3%. HNO3 decreased the sensitivity. Cold vapor AAS was suitable for lower Hg concentrations. The use of NaBH4 was preferred since the signal did not depend on acid concentration and type. Digestion with HCl or aqua regia was suitable. Calibration graphs using standard additions were linear for 2-20 µg/l Hg and the recoveries were 97-102%.
Mercury Environmental Spectrophotometry Spectrophotometry Sample preparation

"Critical Comparison Of Methods For Mercury Determination In Fish"
Microchim. Acta 1995 Volume 119, Issue 3-4 Pages 305-310
Angelo Bortoli, Michele Gerotto, Maurizio Marchiori, Herbert Muntau and Albert Rehnert

Abstract: Fish was analyzed for Hg by solid-sampling ETAAS using Zeeman background correction without prior mineralization of the sample (no other details given), and by flow injection cold vapor AAS using either microwave or closed pressurized wet digestion. For microwave digestion, homogenized sample (0.5 g in 5 mL concentrated HNO3) was microwaved (Milestone Model MLS 1200), cooled, mixed with 1 mL 35% H2O2, then microwaved again (no operating details given). For pressurized digestion, sample (200 mg) was heated with 1.5 mL concentrated HNO3 at 170°C for 16 h. AAS was performed using a Perkin Elmer 2100 instrument equipped with cold vapor system FIAS 200, using 3% HCl as carrier and 0.1% NaBH4 in 0.05% NaOH as reducing agent (no other details given). Standard additions calibration was used. The recovery for microwave digestion was 98%. The solid-sampling ETAAS method gave better precision. No calibration data, detection limits or RSD are given. Results (tabulated) obtained using the three methods correlated well.
Mercury Marine Spectrophotometry Sample preparation

"Analysis Of Carbide And Intermetallic Phase γ Isolates In Nickel Alloys By Means Of Injection Method Of Flame Atomic Absorption Spectrometry"
Microchim. Acta 1987 Volume 91, Issue 1-6 Pages 201-209
Andrzej Wyci&#347;lik

Abstract: The construction of a PTFE crater manifold and a portable capillary bearing is described for use in a flow injection AAS method for analysis of carbide and intermetallic phase γ' isolates in nickel alloys. The γ' phase was isolated by anodic dissolution in HClO4 - HNO3 - methanol. The isolate was dissolved in HNO3 - HF - water and the solution was evaporated to dryness; the residue was heated to boiling with HCl and HF, NH4F was added to the cooled solution and the solution was diluted with water. Niobium and Ta were determined by the method of Welcher and Kriege (At. Absorption Newsl., 1969, 8, 97); Al, Ti and V were determined by the standard-additions method; the carbide isolates were analyzed by the method of Sauer and Nitsche (Arch. Eisenhuettenwes., 1969, 40, 891). The coefficient of variation for Al, Ti, Mo, Co, W, Nb, Cr and Ta were 3.5 to 4.2, 4.1 to 4.6, 3.8 to 4.2, 2.5 to 2.8, 8.6 to 8.8, 11.2 to 11.6, 3.1 to 3.4 and 10.2 to 10.6%, respectively.
Metals, trace Aluminum Titanium Molybdenum Cobalt Tungsten Niobium Chromium Tantalum Alloy Spectrophotometry

"Organic-phase Enzyme Electrode For The Determination Of Phenols In Olive Oils"
Anal. Lett. 1992 Volume 25, Issue 8 Pages 1399-1409
Wang, J.;Reviejo, A.J.;Mannino, S.

Abstract: A polished graphite disc (3 mm diameter) was covered with a solution of tyrosinase in 0.05 M phosphate buffer (pH 7.4) and was dried with a heat gun. Olive oil was dissolved in CHCl3 containing 0.1 M tetrabutylammonium bromide and saturated with the phosphate buffer. Amperometric wall-jet detection of phenols was performed at -0.2 V in a flow injection system (0.4 mL min-1) with a 20 µL sample loop. Quantitation was effected by the standard-additions method. The detection limit was 0.4 µM (0.8 ng) of phenol with an analysis rate of 60 samples h-1. The calibration graph was rectilinear up to 0.6 mM.
Phenols Oil Electrode Amperometry Electrode Electrode

"Flow Injection Spectrophotometric Determination Of Free And Total Sulfite In Wines Based On The Induced Oxidation Of Manganese(II)"
Anal. Lett. 1998 Volume 31, Issue 13 Pages 2195-2208
Rosa Lina G. N. P. Silva; Cintia S. Silva; Joaquim A. N&oacute;brega; Eduardo A. Neves

Abstract: The sulfur(IV) content in wines was determined with a flow injection spectrophotometric system by treating each sample in the donor channel with sulfuric acid to release free SO2, which diffuses through a PTFE membrane to the acceptor solution containing Mn(II) in acetate buffer at pH 5.5. The induced oxidation of Mn(II) takes place proportionally to the free S(IV) content and the oxidized species formed reacts with iodide to form iodine which can be spectrophotometrically measured at 352 nm. A linear plot of absorbance vs. S(IV) concentration. is observed up to 26 mg SO2/L with a detection limit of 1.0 mg/L. Matrix effects required the standard additions of sulfite to the samples for obtaining accurate results. A previous treatment of the sample with tris(hydroxymethylaminomethane) and EDTA decomposed the hydrogen-sulfite/aldehyde adducts and allowed the determination of the total S(IV) content. As expected, total S(IV) concentration. in wines has been found to be much higher than free sulfite. A recovery-addition experiment with red and white wines led to recoveries varying from 91.5 to 109.7% by applying the free and total sulfite developed procedures. This is a good indication of the accuracy of both proposed procedures.
Sulfite Wine Red Wine White Spectrophotometry

"Square-wave Adsorptive Stripping Voltammetry Of Nickel(II) In Flowing Systems At A Wall-jet Mercury-film Electrode Plated In Situ"
Electroanalysis 1997 Volume 9, Issue 2 Pages 145-149
Maria M. G. S. Rocha*, Maria M. P. M. Neto, Maria Odete Torres, Amarilis de Varennes

Abstract: In a voltammetric cell the sample solution was pumped at 45 nl/s into 0.1 M KNO3/50 µM-mercury(II) nitrate/0.2 mM dimethylglyoxime with pH adjusted to 9 with KOH. The cell also contains a 0.327 cm2 glassy C disc wall-jet electrode 3 cm from the sample inlet, a saturated KCl/Ag/AgCl reference electrode and a Pt tube counter electrode and cell outlet. The Hg and Ni-dimethylglyoxime complex were adsorbed for 1 min onto the wall-jet electrode at -0.8 V vs. reference electrode before square-wave stripping voltammetry in the negative direction at an amplitude of 50 mV, a frequency of 60 Hz and a step of 5 mV. After 1 h use, the wall-jet electrode was cleaned for 1 min at +0.4 V. Calibration graphs were linear for 0.8 nM to 0.25 µM-Ni(II) with a detection limit of 130 pM. There was no interference from a 10 000-fold excess of Cr(III), Fe(III), Co(II), Cd(II), Hg(II) and Pb(II) but a 5000- and 3000-fold excess of Zn(II) and Mn(II), respectively, interfered. The use of standard additions is recommended for quantification. The method should be useful for the continuous online monitoring of Ni.
Nickel(II) Voltammetry Electrode Electrode Electrode

"Amperometric Differential Determination Of Ascorbic Acid In Beverages And Vitamin C Tablets Using A Flow Cell Containing An Array Of Gold Microelectrodes Modified With Palladium"
Electroanalysis 1998 Volume 10, Issue 13 Pages 887-890
Renato C. Matos, M&aacute;rcio A. Augelli, Jairo J. Pedrotti, Claudimir L. Lago, L&uacute;cio Angnes

Abstract: A simple and attractive method for quantification of ascorbic acid (AA) in beers, soda, natural juices, and commercial vitamin C tablets was developed by combining flow injection analysis and amperometric detection. An array of Au microelectrodes electrochemically modified by deposition of Pd was employed as working electrode which was almost unaffected by fouling effects. AA was quantified in beverages and vitamin tablets using amperometric differential measurements. The method is based on three steps involving the flow injection of the sample plus a standard addition of AA, of the pure sample, and of the enzymatically-treated sample. The enzymatic treatment was carried out with Cucumis sativus tissue, which is a rich source of ascorbate oxidase, at pH 7. The calibration plots for freshly prepared AA standards were linear in the concentration. range of 0.18-1.8 mg/L with a relative standard deviation (RSD) <1%, while for real samples the deviations were 2.7-8.9%.
Ascorbic acid Beer Soft drink Fruit Pharmaceutical Amperometry Electrode Electrode

"Determination Of Anti-carcinogenic Polyphenols Present In Green Tea Using Capillary Electrophoresis Coupled To A Flow Injection System"
J. Chromatogr. A 1998 Volume 827, Issue 1 Pages 113-120
Lourdes Arce, Angel R&iacute;os and Miguel Valc&aacute;rcel*

Abstract: A capillary electrophoresis (CE) method was developed for the simultaneous determination of a number of major ingredients of green tea. The components analyzed were caffeine, adenine, theophylline, epigallocatechin 3-gallate, epigallocatechin, epicatechin 3-gallate, (-)-epicatechin, (+)-catechin, gallic acid, quercetin and caffeic acid. Separation was achieved using a fused capillary column with 0.15 M H3BO3 as buffer at a pH of 8.5, UV detection at 210 nm and 20 kV of voltage. Analysis was carried out after treatment (extraction, filtration and dilution) of the samples in a flow injection system which was coupled to a CE equipment via a programmable arm. The procedure allows the determination of these compounds in <20 min. Quantitative analysis was performed by the standard addition method. Limits of detection ranged between 0.04 µg/mL for flavonols and 1.2 µg/mL for caffeine.
Polyphenols Caffeine Adenine Theophylline Epigallocatechin 3-gallate Epigallocatechin Epicatechin 3-gallate Epicatechin Catechin Gallic acid Quercetin Caffeic acid Leaves Electrophoresis Spectrophotometry

"Electrochemistry Of Ascorbic Acid At Polypyrrole-dodecyl Sulfate Film-coated Electrodes And Its Application"
J. Electroanal. Chem. 1994 Volume 365, Issue 1-2 Pages 197-205
Zhiqiang Gao*, Beshen Chen and Minxian Zi

Abstract: The voltammetric, amperometric and chronoamperometric behavior of ascorbic acid at such electrodes involved an oxidation peak at ~0 V (vs. SCE), i.e., 300 mV more negative than at an uncoated electrode. The properties of such electrodes were superior to polypyrrole films prepared in solution of inorganic anions. The low oxidation potential rendered the proposed electrodes suitable for the FIA determination of ascorbic acid. The RSD at the 30-50 mg level in single- and multi-vitamin tablets were 5.0%, and recoveries of standard additions to these sample solution were 94-107%.
Ascorbic acid Pharmaceutical Voltammetry Amperometry Electrode

"Investigation Of Online Coupling Electrothermal Atomic Absorption Spectrometry With Flow Injection Sorption Preconcentration Using A Knotted Reactor For Totally Automatic Determination Of Lead In Water Samples"
Spectrochim. Acta B 1996 Volume 51, Issue 14 Pages 1891-1908
Michael Sperling*, Xiu-ping Yan and Bernhard Welz

Abstract: Diagrams and a table of the valve sequence of the manifold are presented;incorporates a knotted reactor of PTFE tubing (1 m x 0.5 mm i.d.) on which the Pb(II)-diethyliocarbamate complex (cf. Welz et al., Appl. Sp ectrosc., 1991, 45, 1433) was collected and from which, after drying with a stream of air, the complex was eluted with 50 µL of ethanol and propelled by air to an AS-70 furnace autosampler for Zeeman AAS with use of a transversely heated graphite atomizer (heating program tabulated). The enhancement factor for 0.01-0.05 µg/l of Pb collected at a loading rate of 6.8 ml/min for 1 min was 142 (detection limit 2 ng/l), and for 0.1-2 µg/l at 3 ml/min for 30 s was 21. The RSD (n = 7) at 0.01 and 0.5 µg/l of Pb were 4.9 and 2.9%, respectively. Application to seawater necessitated use of the method of standard additions. Results for standard reference water samples agreed well with the certified values.
Lead Sea Spectrophotometry

"Determination Of Arsenic, Antimony, Bismuth And Mercury In Water Samples By Flow Injection Inductively Coupled Plasma Mass Spectrometry With An In Situ Nebulizer/hydride Generator"
Spectrochim. Acta B 1996 Volume 51, Issue 14 Pages 1813-1821
Chih-Shyue Chen and Shiuh-Jen Jiang*

Abstract: The sample (0.2 mL) is injected into a stream (1 mL/min) of 0.5% cysteine solution in 0.05 M HNO3 that then merges with a stream (1 mL/min) of 0.2% NaBH4 solution in 0.02 M NaOH. The combined streams then pass to a crossflow pneumatic nebulizer with a Scott-type spray chamber for introduction into the ICP of an ELAN 5000 ICP-MS instrument; at the instrument settings tabulated, one data point could be recorded per s. Either the height or area of the flow injection peak could be used as the signal; calibration graphs based on peak heights were linear for 0.1-10 ng/mL of the cited elements, and the detection limits were 3, 17, 3 and 170 pg/mL, respectively. Both direct calibration and the method of standard additions gave satisfactory results for tap water, but for river and seawater use of the method of standard additions was necessary; for seawater it was also necessary to correct for the interference from 40Ar35Cl+ with the determination of 75As+ (equation given).
Antimony Arsenic Bismuth Mercury Water River Sea Environmental Mass spectrometry

"Determination Of Trace Concentrations Of Bismuth By Inductively Coupled Plasma Atomic-emission Spectrometry With Hydride Generation"
Spectrochim. Acta B 1987 Volume 42, Issue 1-2 Pages 119-128
Taketoshi Nakahara, Kuniyuki Nakanishi and Tamotsu Wasa

Abstract: The continuous-flow hydride-generation apparatus used was as described previously (Anal. Chim. Acta, 1981, 131, 73; Appl. Spectrosc., 1983, 37, 539). The sample solution in 1 M HCl and 1% NaBH4 solution in 1% NaOH were pumped at 16 and 5.5 mL min-1, respectively, and the BiH3 evolved was carried to the ICP in a stream of Ar for the emission intensity at 223.06 nm to be measured. The instrumental coefficient of variation (n = 10) for 0.5, 2, 20 and 200 ng mL-1 of Bi were 3.5, 2.8, 2.2 and 1.3%, respectively, the limit of detection was 0.35 ng mL-1, and a graph of emission intensity vs. log. Bi concentration. was rectilinear for ~1 ng mL-1 to ~10 µg mL-1. The method of standard additions was used for actual determinations, in the presence of 0.1 M thiourea to minimize interference. Results for various geological reference standards, standard copper and standard aluminum alloys (digestion procedures described) agreed well with reported or certified values.
Bismuth Alloy Metal Geological Spectrophotometry Sample preparation

"The Determination Of Tin In Steel Samples By Flow Injection Hydride Generation Atomic Absorption Spectroscopy"
Spectrochim. Acta B 1992 Volume 47, Issue 7 Pages 897-906
Susan McIntosh, Zhang Li, Glen R. Carnrick and Walter Slavin*

Abstract: Copper, Ni and Co interfere in the cited determination. The interference occurs in the generation of hydride and not during the atomization of gaseous hydride. Tin was also determined in iron and river sediment samples. Hydride generation was in a saturated boric acid solution with a carrier solution of 2% HCl. Sample digestion in a pressure bomb was compared with that in aqua regia at 1 atmosphere. An Ar and O2 gas stream gas stream gave better sensitivity and peak symmetry than a pure Ar gas stream. The detection limit was 0.05 µg L-1 in a 500 µL sample with a coefficient of variation of 1 to 3% at higher concentration. of Sn. Conditions were studied for the determination of Sn in steel samples using flow injection, hydride generation, and atomic absorption spectroscopy. Interferences were found for the determination of Sn in steel samples and an investigation showed that the interferences occurred in the generation of the hydride, not in the atomization of the gaseous hydride. Conditions for the determination of Sn by flow injection hydride generation were improved by using integrated absorbance signals and by the addition of oxygen to the argon carrier gas stream. Typically, 500 µL of a 10 µg/L Sn standard provided an integrated absorbance signal greater than 0.5 A s. The method provided a detection limit of about 0.05 µg/L in a 500 µL sample. The precision ranged from 1 to 3% RSD at higher concentration levels of Sn. The method of additions yielded accurate results for several steel standard reference materials in those situations where the use of the standard calibration procedure was inadequate.
Tin Alloy Metal River Spectrophotometry Sample preparation

"Determination Of Selenium In Urine By Flow Injection Hydride Generation Electrothermal Atomic Absorption Spectrometry With In-atomizer Trapping"
Spectrochim. Acta B 1997 Volume 52, Issue 12 Pages 1773-1781
Julian F. Tysona,*, Nils G. Sundina, Christopher P. Hannab and Susan A. McIntoshb

Abstract: Following digestion of the sample in a mixture of bromate and hydrobromic acid, the inorganic selenium produced was quantified by trapping hydrogen selenide, formed when a 500 µL sample volume injected into a hydrochloric acid carrier stream merged with a stream of sodium borohydride solution, on the iridium-pretreated interior of a graphite furnace atomizer. A number of parameters relating to the digestion, flow injection manifold and trapping in the atomizer were investigated, including a study of factors affecting the detection limit. It was found necessary to heat the digest under reflux at a temperature of 150°C for 2 h. Quantitative recoveries, from a human urine matrix, of selenite, selenate, trimethylselenium, selenocystine, selenopurine and selenomethionine spikes were obtained. The efficiency of hydride generation, transport and trapping was 75%. The major factors affecting the detection limit were the reagent purity and the volume injected. For high-purity hydrobromic acid and borohydride free of caking agent, the detection limit, based on three times the standard deviation of the blank, was 0.06 µg L-1 for a 1000 µL injection volume corresponding to a detection limit of 3 µg L-1 for a urine sample. The method was validated by the accurate analyzes of Standard Reference Material 2670 from the National Institute of Standards and Technology, and urine samples from an interlaboratory comparison program. The procedure avoids the need for perchloric acid and produces selenium in the + 4 oxidation state and thus no reduction is needed prior to generation of the hydrogen selenide. The use of a graphite furnace atomizer avoids the need for frequent reconditioning of the atomizer surface and the need for the standard additions method, both of which are drawbacks of procedures which make use of the quartz tube atomizer. All sample handling procedures following the digestion were automated by the use of flow injection technology.
Selenium Urine NIST 2670 Spectrophotometry Sample preparation

"The Application Of Flow Injection Iminodiacetic Acid-ethylcellulose Membrane Preconcentration And Separation Technique To Atomic Spectrometry"
Spectrochim. Acta B 1998 Volume 53, Issue 10 Pages 1437-1445
Xiaoru Wang*, Zhixia Zuang, Chenlong Yang and Fan Zhyu

Abstract: A flow injection-based online iminodiacetic acid-ethylcellulose (IDAEC) membrane pre-concentration. and separation technique was developed, which has the advantages of easy operation without membrane plugging problems; a high enrichment factor (>10 for most elements); a high sample throughput (30 samples/h). The characteristics of the IDAEC membrane were systematically studied, including the effect of sample flow rate and analyte concentration. on break-through point; dynamic capacity and the lifetime of the IDAEC membrane. The technique was applied to pond water and seawater anal. in which all elements studied are in ng/mL level. The anal. performance was verified with recovery of a standard addition from seawater.
Pond Sea Spectrophotometry

"Immobilized Enzyme Flow Injection Conductimetric System For The Determination Of Acetylcholine"
Anal. Proc. 1995 Volume 32, Issue 8 Pages 333-335
Oswaldo E. S. Godinho, Tereza C. Rodrigues, Matthieu Tubino, Graciliano de Oliveira Neto and Luiz M. Aleixo

Abstract: Portions of acetylcholine (I) standard solutions were injected into a carrier stream of 0.1 M phosphate buffer of pH 7.4 at 1.19 ml/min and passed through a polyethylene tube (3.5 cm x 3 mm diameter) containing immobilized acetylcholinesterase immobilized on glass beads. The solution was merged with a stream of 2 M H2SO4 at 1.19 ml/min and passed through a PTFE membrane diffusion cell. The acetic acid that diffused through the membrane was carried by a stream of water to a conductimetric cell. The calibration graph was linear from 10 µm to 1 mM I. The method was applied to the analysis of I in a pharmaceutical formulation (details given). Recoveries, by the standard additions method were 100-107.8% for 9-36 µM of added I. With this method, 24 analyzes were performed in 1 h and the enzyme reactor was used for 4 months without loss of activity.
Acetylcholine Pharmaceutical Conductometry

"Study On The Sourness Of Food And Its Electrochemical Measurement. 7. Conductometric Flow Injection Analysis Of The Organic Acid Content In Citrus Fruits"
Agric. Biol. Chem. 1984 Volume 48, Issue 9 Pages 2211-2215
Kiyoshi MATSUMOTO, Koh-ichi ISHIDA, Takakazu NOMURA and Yutaka OSAJIMA

Abstract: A flow injection system, incorporating a flow-through four-electrode cell for controlled-potential conductance measurements, is described. For the analysis, a sample (35 µL) of pure centrifuged fruit juice was injected into the carrier stream (flow rate 20 mL min-1), and the mixing-coil length was 100 cm. There was good correlation (r = 0.992) between peak conductance and acid content (as shown by addition of malic and citric acids to the juice). By this method, 50 samples could be analyzed in 1 h, and the coefficient of variation of the results for any given juice was 0.5% (n = 20). To reduce the viscosity of the juice, dilution (1:3 or 1:4) before injection is recommended.
Acids, carboxylic Juice Conductometry Electrode Conductometry

"Determination Of Aluminum In Serum By A Flow Injection System With Preconcentration On Dowex A-1 Resin And Flame Atomic Absorption Spectrophotometry"
An. Quim. 1987 Volume 83, Issue 1B Pages 95-100
Hernandez, P.;Rodriguez, J.;Sevilla, M.T.;Hernandez, L.

Abstract: Serum (2 ml) is treated with 0.3 mL of HClO4 and 0.7 mL of concentrated HNO3 in a platinum capsule, the solution is evaporated just to dryness, and the residue is dissolved in 2 mL of 0.4 M acetic acid - ammonium acetate buffer of pH 4. A 1 mL portion of this solution is injected into a stream of the same buffer which passes through a 5.4-cm bed of Dowex A-1 resin, on which the Al is adsorbed. The Al is directly eluted by 6.0 M HNO3 into the nebulizer of a flame AAS instrument for determination at 390 nm. The lower limit of 50 µg L-1 of Al can be improved by using the standard-additions method, which affords a coefficient of variation of 2.0% at 15 µg l-1.
Aluminum Blood Serum Ion exchange Spectrophotometry

"Optimized Microwave Digestion Procedure For Cadmium Analysis Of Mussel Samples"
Analusis 1998 Volume 26, Issue 7 Pages 261-263
M.C. Yebra and M.F. Enr&iacute;quez

Abstract: A simple and rapid acid sample digestion method by microwave heating in high-pressure teflon bombs is reported for the determination of cadmium in mussels by flame atomic absorption spectrometry (FAAS) coupled online with a flow injection pre-concentration system. Tests concerning the digestion time, the power of the microwaves and the amt. of nitric acid were studied with the National Research Council of Canada lobster hepatopancreas marine (Tort-1) as certified reference material. Using 2 min of digestion time and 2 mL of nitric acid, the complete dissolution of 0.2 g of freeze-dried sample is possible. The anal. results, obtained with calibration graph as well as by the standard addition method, were agreed well with the certified value of the reference material. This procedure was applied to the determination of cadmium in mussel samples from estuaries in Galicia, Spain.
Cadmium Mussel NRCC TORT-1 Sample preparation Spectrophotometry

"Determination Of Copper(II) At Sub-picogram Level By Flow Injection Method Using Micellar-enhanced Chemiluminescence Of 1,10-phenanthroline: Application To Rabbit Lens"
Bunseki Kagaku 1986 Volume 35, Issue 4 Pages 379-383
Ishii, M.;Yamada, M.;Suzuki, S.

Abstract: Rabbit lens was dissolved in concentrated HCl by heating, and the solution was diluted with water before analysis by the 1,10-phenanthroline flow injection method (Ibid., 1986, 35, 373; see Section H of this issue) with standard additions. The limits of determination and detection were 5.5 and 0.6 pg mL-1 of Cu(II), respectively (20 µL injection). The coefficient of variation was <1.9% and the results correlated well (r = 0.94) with those obtained by AAS. Zinc and Pb gave signals 0.01% of that for Cu.
Copper(II) Rabbit Eye Lens Chemiluminescence

"Spectrophotometric Determination Of Cobalt In High-salt Concentration Solutions By Flow Injection Method"
Bunseki Kagaku 1992 Volume 41, Issue 12 Pages 633-638
Hayashibe, Y.;Takeya, M.;Sayama, Y.

Abstract: Sample solution (Zn electrolyte for wet-refining containing ~150 g L-1 of Zn) was injected in four 1 mL portions (separated in time by 90 s) into a stream of 0.25 M H2SO4 which merged with a stream of acetate - citrate buffer solution of pH 6. Then 1% nitroso-R salt solution was injected in two 62 µL portions (separated by 90 s), the first coinciding with the last sample injection, and after passage through a 3-m mixing coil at 120°C the stream merged with a stream of 0.25% (v/v) H2O2 in 1 M H2SO4. After further mixing in a 3-m coil at 120°C, the absorbance was measured at 480 nm. Before the determination, the reagent alone was injected to measure the background absorbance, and the method of standard additions was used. The sampling rate was 6 h-1. The coefficient of variation (n = 3) for the determination of 0.5 µg mL-1 of Co was 8.0%; the detection limit was 0.05 µg mL-1 of Co. A flow injection method has been studied for the determination of cobalt in high-salt concentration. (zinc electrolyte) solutions to be used for wet refining. The sample solution containing about 150 g Zn L-1 was injected four times into a carrier stream, and the carrier stream was merged with 2 M acetate-0.5 M citrate buffer solution (pH 6) to form a sample solution stream. The colorimetric reagent (1.0% (wt./v) nitroso-R salt) was injected into the sample solution stream. Then coexisting metal complexes were decomposed by mixing with 2 M sulfuric acid-1% (by volume) hydrogen peroxide solution. Finally, the absorbance of cobalt complex was measured at 480 nm. Just before the determination of Co, colorimetric reagent alone was injected into the anal. system for the measurement of background absorbance, and the background absorbance was utilized for the correction of the system variation. A calibration curve was constructed by using solutions prepared by adding various increments of the standard cobalt solution to the real sample solution, of which cobalt concentration. had been determined by a combined solvent extraction/graphite furnace-at. absorption spectrometric method. The proposed system was operated automatically by a personal computer and allowed 6 samples to analyze per h. Precision of the system was 8% (relative standard deviation) at the 0.5 µg Co mL-1 level and detection limit was 0.05 µg Co mL-1.
Cobalt Zinc Spectrophotometry

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

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

"Flow Injection Calibration Procedures With The Use Of Fully Rotary Valve"
Chem. Anal. 1996 Volume 41, Issue 1 Pages 85-93
Koscielniak, P.;Janiszewska, J.;Fang, Z.L.

Abstract: An injection valve capable of rotating fully (360°C) in relation to the stator (diagram given) was developed. It allowed calibration to be performed using a single standard solution, by sequential injection of standards using loops of different volumes. The operation of the valve in FIA systems using the calibration graph method and the standard additions method for calibration is described. The valve was tested for determination of 8-36 mM Cr using a single calibration solution containing 40 mM Cr.
Chromium

"Simultaneous Determination Of Titanium, Molybdenum And Tungsten With A Synergic Effect Compensating Flow Injection Multi-standard Additions Method"
Chem. Anal. 1996 Volume 41, Issue 4 Pages 577-586
Wang, J.H.;He, R.H.;Tong, Y.H.

Abstract: Sample (40 µL) was injected into a carrier stream (2 ml/min) of dilute H2SO4 of pH 1.35 and mixed with a stream (2 ml/min) of 0.125 mM salicyl fluoron solution of pH 1.35 in a reaction coil (10 cm x 0.8 mm i.d.). The flow then merged with a stream (2 ml/min) of 2.5 mM cetyltrimethylammonium bromide of pH 1.35 and passed through a reaction coil (220 cm x 0.8 mm i.d.) and the absorbance was measured at 520 nm. Simultaneous determination of Ti, Mo and W was achieved using the standard additions method; synergic effects between the analytes leading to absorbance deviations were compensated for using a defined ternary system coefficient. Calibration graphs were linear for 0.05-0.35 µg/ml Mo, 0.025-0.3 µg/ml Ti and 0.25-1 µg/ml W. Recoveries from steel and simulated samples were 92.3-104.7%, 91.2-105.2% and 90.6-107.3%, respectively. A flow injection spectrophotometric multi-standard additions method had been proposed, and the principle of simultaneous determination for an interfering ternary component mixtures was discussed. The deviations of absorbance from additivity, caused by synergetic effects between the analytes, were compensated with the defined ternary-system synergetic coefficient. The color reactions of titanium(IV), molybdenum(VI) or tungsten(VI) with cetyltrimethylammonium bromide and salicyl fluoron I were studied, and the conditions for simultaneous determination of them were established. Tile linear concentration ranges of determination were 0.05-0.35 µg mL-1 Mo, 0.025-0.30 µg mL-1 Ti and 0.25-1.00 µg mL-1 W. Titanium, molybdenum and tungsten contents in a steel and simulated samples were determined, the recoveries For titanium, molybdenum and tungsten were 91.2-105.2%, 92.3-104.7% and 90.6-107.3%, respectively.
Titanium Molybdenum Tungsten Alloy Spectrophotometry

"The Application Of Online Standard Addition Method In Microwave Plasma Torch Atomic-emission Spectrometry"
Gaodeng Xuexiao Huaxue Xuebao 1995 Volume 16, Issue 12 Pages 1871-1873
Ye, D.M.;Zhang, H.Q.;Yu, J.L.;Jin, Q.H.

Abstract: In this paper, the probability of eliminating matrix interferences in MPT-AES by online standard addition method was studied, The dynamic linear range of Cu and Mg is 0.05 similar to 80 µg/mL. The relative standard deviations of them are 3.02% (1.0 µg/mL, n = 7), and 4.47% (1.0 µg/mL, n = 7) respectively. The results indicated that this method can eliminate matrix interferences and is useful in real sample analysis, The operation of this system is simple. (9 references)
Calcium Magnesium Spectrophotometry

"Determination Of Magnesium By Flame AAS Detection With Flow Injection Analysis"
Chem. Pap. 1990 Volume 44, Issue 3 Pages 339-346
Kuban, V.;Komarek, J.;Cajkova, D.;Zdrahal, Z.

Abstract: The single-channel experimental arrangement (cf. Gallego et al., Atomic Spectrosc., 1985, 6, 16) included a capillary dispersing flow injection system of PTFE capillaries with a pulse-free flow of carrier medium provided by hydrostatic pressure, a rotatory loop injector, and an AAS instrument with a Mg hollow cathode lamp and an acetylene - air flame at a slot burner. The sample of an aluminate luminophore (Ba0.9Mg2Al16O27Eu0.1) was fused with Na2CO3 and Na2B4O7, the melt was dissolved in warm 2 M HCl, and the solution was diluted to be 0.1 M in HCl before injection (20 µL volume) into 1% sulfosalicylic acid solution as carrier. The effects of carrier medium, injected sample volume, length of dispersion coil and flow rate on the absorption signal were evaluated. Calibration procedures based on peak heights, peak areas or peak widths at constant height gave rectilinear graphs up to 1.5, 2.0 and 1000 µg mL-1, respectively, of Mg in the injected solution. A reverse standard-additions method gave good precision and overcame the effects of interfering substances. Recovery of 2.5 µg mL-1 of Mg added to luminophore solution was quantitative; for 125 µg mL-1 the repeatability was 2.5% (n = 10).
Magnesium Spectrophotometry

"Application Of Flow Injection Analysis To The Determination Of Germanium"
Chem. Pharm. Bull. 1989 Volume 37, Issue 4 Pages 1095-1096
Shimada, K.;Nakajima, M.;Wakabayashi, H.;Yamato, S.

Abstract: Sample solution (50 µL) is injected into a carrier stream of ethanol (0.5 mL min-1) that then merges with a stream (0.42 mL min-1) of 0.002% phenylfluorine solution in ethanolic 0.43% HCl. After passage through a PTFE reaction coil (3 m x 0.5 mm) in an oil bath at 40°C, the absorbance is measured at 508 nm. The calibration graph was rectilinear up to 500 ng of Ge, and the coefficient of variation (n = 5) for 100 to 500 ng was 2%. The method was applied to a commercial health beverage with use of the method of standard additions. Interference was generally negligible.
Germanium Nutritional Spectrophotometry

"Spectrophotometric Determination Of Ascorbic Acid In Vitamin C Tablets, Beverages, Orange And Urine With 2,6-dichloroindophenol By Flow Injection Analysis"
Fenxi Huaxue 1991 Volume 19, Issue 2 Pages 182-184
Ma, H.C.;Feng, J.Z.;Cao, B.

Abstract: Sample is injected into a carrier stream of potassium hydrogen phthalate buffer of pH 3.6 (2 mL min-1) for reaction with a reagent stream of 0.2 mM dichloroindophenol (1.5 mL min-1) in a 15-cm reaction coil before kinetic spectrophotometric detection at 525 nm. For the analysis of vitamin C tablets, oranges, beverages and urine by use of the standard-additions method, recovery was 72 to 117%. For 50 µg mL-1 of I, the coefficient of variation was 0.5%. Detection limit was 0.5 µg mL-1. The calibration graph was rectilinear up to 50 µg mL-1. Interference was observed from Fe(III); most co-existing ions (e.g., Zn and Cu), sugars, amino-acids and organic acids (such as citric acid) did not interfere.
Ascorbic acid Beverage Urine Juice Pharmaceutical Spectrophotometry

"Determination Of Arsenic, Antimony And Bismuth By Inductively Coupled Plasma Atomic-emission Spectrometry With Flow Injection Analysis And Hydride Generation"
Fenxi Huaxue 1991 Volume 19, Issue 11 Pages 1285-1287
Gao, H.;Li, K.

Abstract: A 0.175-g ore or rock sample was wetted with a little water and then dissolved in 9 mL of HCl plus 3 mL of HNO3 and 1 mL of H2SO4 (1:1); after evaporation to fumes and cooling, 2.5 mL of HCl, 5 mL of 10% KI - 5% ascorbic acid - 5% thiourea solution and water were added to 25 mL. The solution was then carried at a flow-rate of 11 mL min-1 to react with 1% KBH4 solution (containing 0.2% of NaOH) at 5.5 mL min-1 in the flow injection system (diagram pesented), and the generated hydrides were carried by Ar (0.6 l min-1) for separation by a gas separator before passing to a direct-reading spectrometer for ICP-AES determination of As, Sb and Bi with measurement at 193.76, 217.5 and 306.7 nm, respectively. By the standard-additions method, recoveries were 94 to 107%. Determination ranges for As, Sb and Bi were up to 1000, 300 and 300 µg g-1, respectively, and their corresponding detection limits were 0.2, 0.2 and 0.1 µg g-1. Masking agents could be used to increase tolerance levels of the co-existing ions; background interferences in the gas phase could be corrected for.
Antimony Arsenic Bismuth Geological Geological Spectrophotometry

"Determination Of Ascorbic Acid In Pharmaceutical Products By Flow Injection Spectrophotometry With Iron(III) - 1,10-phenanthroline"
Fenxi Huaxue 1992 Volume 20, Issue 2 Pages 193-195
Fu, L.;Ren, Y.

Abstract: Vitamin C injection was diluted with water, before injection into a flow injection analyzer. and mixing with a reagent stream of pH ~3 at 2 mL min-1 for reaction in a reaction tube with detection at 508 nm. The reagent was prepared from 0.16 g of NH4Fe(SO4)2, 1 mL of 0.8 M H2SO4, 0.1982 g of 1,10-phenanthroline and water to 100 ml, with dilution of 2 mL of the solution to 25 mL with water. Quantitation was by the standard-additions method. Recovery was 92 to 103%; the coefficient of variation (n = 11) were 0.5%. The calibration graph was rectilinear up to 16 µg mL-1 of ascorbic acid. Only Cu(II) interfered seriously. The method was also applied to vitamin C tablets and compound vitamins with a sampling rate of 60 h-1.
Ascorbic acid Pharmaceutical Spectrophotometry

"Interpolative Standard Addition Method In Anodic-stripping Voltammetry With Flow Injection System"
Fenxi Huaxue 1992 Volume 20, Issue 6 Pages 633-637
Gao, G.;Deng, Y.;Qi, D.

Abstract: A new interpolative standard addition method in flow injection analysis (FIA) systems with anodic-stripping voltammetry was developed and a theoretical equation for the stripping peak current under this nonsteady deposition procedure was proposed. With this technique the concentration. of sample (used as carrier) was obtained rapidly by a proposed simple equation only after injecting a standard. The system was applied to the determination of Pb in tap water. Filtered sample was directly injected into the FIA system at 0.6 mL min-1 to merge with a reagent stream of 0.5 M KCl - 0.2 M HCl - 0.1 M ascorbic acid at 0.06 mL min-1 before anodic-stripping voltammetry with use of water as blank and 20 nM-Pb(II) as standard solution Lead was calculated using a given equation. Recovery was 90 to 108%; coefficient of variation (n = 10) was 3.4%. The detection limit was at the ppb level. Results were comparable with those obtained by the conventional anodic-stripping voltammetry.
Lead Water Sample preparation Voltammetry

"Kinetic Double Standard Addition Method For The Simultaneous Determination Of Molybdenum And Tungsten"
Fenxi Huaxue 1995 Volume 23, Issue 4 Pages 442-445
Wang, J.H.;Chang, J.Z.;Yuan, Y.L.;Jiang, Z.M.

Abstract: The sample was injected over 10 s into the flow injection system and carried by a stream of aqueous 0.1% starch solution of pH 2.6 to react with streams of 9.7 mM H2O2 of pH 2.6 and 15 mM KI (all 3 ml/min) in a PTFE tube (30 cm x 0.8 mm i.d.) at 28°C while the flow was stopped for 40 s; detection was at 589 nm. Standard-addition graphs were constructed for determination of Mo(VI) and W(VI). When determining 2 µg/ml of Mo and 0.6 µg/ml of W by this stopped-flow technique, recoveries were 97.5-101.8% and RSD were 2.1-3.5%. The method was applied to steel and simulated samples.
Molybdenum Tungsten Alloy Spectrophotometry

"A Kinetic Dual Standard-additions Method For The Simultaneous Determination Of Interfering Binary Mixtures Compensated By The Synergic Coefficient"
Fenxi Huaxue 1995 Volume 23, Issue 10 Pages 1197-1200
He, R.H.;Wang, J.H.

Abstract: A sample (40 µL) was injected in to a flow injection system to be transported at 2.4 ml/min by a stream of water containing 0.1% starch of pH 3. This stream mixed with 10 mM KI and 9.3 mM water streams (3 ml/min) in a reaction cell (30 cm x 0.5 mm i.d.). Absorbance was measured at 589 nm; stop-flow time was 30 s. Using the data amounts of the two unknown components were calculated (equation given). The method was applied to the simultaneous determination of Mo(VI) and W(VI) in synthetic samples; recoveries were 98.2-101.5% and RSD were 1.8-2%. Most co-existing ions were tolerated. Deviation of absorbance due to additivity was effectively eliminated.
Molybdenum(VI) Tungsten(VI) Spectrophotometry

"Simultaneous Determination Of Chromium(III) And Chromium(VI) In Waste Water With Flow Injection Analysis Monitored By Chemiluminescence"
Fenxi Huaxue 1995 Volume 23, Issue 10 Pages 1148-1150
Zhang, H.S.;Yang, X.C.;Wu, L.P.

Abstract: A sample was adjusted to pH 3 and mixed with EDTA to a final concentration of 1 mM before dilution with water and injection in to a flow injection system. The carrier stream transported the sample to the shunt which divided the sample in two; the first portion was reacted directly with a mixture of 0.25 mM luminol and 20 mM H2O2 of pH 12 (2:1) for chemiluminescence measurement. The second portion was passed through a reduction column (2.5 cm x 2 mm i.d.) of Cu-coated Zn granules, then through a delay tubing (110 cm) prior to allowing the online generated Cr(III) and original Cr(III) to react with luminol/H2O2 and measuring the chemiluminescence. Calibration graphs were linear from 10 µM-1 nM. Detection limit was 23 nM-Cr(III). Using the standard-additions method, recoveries for Cr(III) and Cr(VI) were 95% and 97%, respectively; corresponding RSD were 0.37-4% and 1.2-4.4%. Sampling frequency was 60 runs per h. The method was applied to the analysis of waste water from a Cr-plating factory. Results were compared with those obtained by diphenylcarbazide photometry. The reduction column lasted >2200 runs.
Chromium(III) Chromium(VI) Waste Chemiluminescence

"Online Determination Of Trace Lead In High-salt Food By Flow Injection Hydride-generation Inductively Coupled Plasma Atomic-emission Spectrometry"
Fenxi Kexue Xuebao 1997 Volume 13, Issue 2 Pages 26-29
Yu Xin, Chen Jianguo, Wang Songqing, Liao Zhenhuan, Jiang Zucheng

Abstract: Salted vegetable (10 g) was homogenized then digested with 8 mL HNO3/HClO4 and evaporated to dryness. The residue was dissolved in 7.5 mL 0.5 M HCl and diluted with water to 25 mL. A 300 µL portion of the solution was injected into the required setup (diagram illustrated) and flowed with a carrier stream of water at 3 ml/min to react with 15% H2O2 to oxidise lower valent Pb to high valent Pb before reaction with a stream of 4% NaBH4 in 0.8% NaOH at 1.5 ml/min, transferring to the gas-liquid separator, and detection of Pb in the Ar flow by ICP-AES with measurement at 220.35 nm. The calibration graph was linear from 0.005-1 µg/ml Pb, with a detection limit of 1.6 ng/ml. When determining 50 ng/ml Pb, the RSD (n = 7) was 1.2%. By the standard-additions method, recoveries were 96.3-101.4%. The method was used in the analysis of e.g. pickled cabbage.
Lead Pickled Vegetable Spectrophotometry

"Application Of Flow Injection Standard Additions Method To ICP-AES For The Analysis Of Mixed Rare-earth Samples"
Fenxi Shiyanshi 1991 Volume 10, Issue 2 Pages 45-47
Shen Qing, Jiang Zucheng and Liao Zhenhuan

Abstract: Sample solution (in place of carrier solution) was pumped continuously to the nebulizer for analysis by ICP-AES and aqueous calibration solution were injected into the stream. Calibration graphs for determination of single rare-earth metals were rectilinear and the coefficient of variation (n = 11) was 4.2%. Recoveries of 3 ppm of Sm, 0.5 ppm of Lu, 1 ppm of Tb, 2 ppm of Pr and 0.8 ppm of Ho were 85 to 112%. The method can be applied in the analysis of mixed rare-earth metal samples.
Metals, rare earth Spectrophotometry

"Flow Injection Spectrophotometric Determination Of Trace Amounts Of Iodide By The 4,4'-methylenebis-(NN-dimethylaniline) Reaction"
Fenxi Shiyanshi 1992 Volume 11, Issue 4 Pages 16-17
Xu, S.K.;Sun, L.;Fang, Z.L.

Abstract: Sample solution is injected into the water carrier stream (1.2 mL min-1) to react with the 0.025% chloramine T oxidant stream (0.6 mL min-1) and then a stream of the cited reagent (prep. described) of pH 4.4 (0.4 mL min-1). The absorbance of the reaction mixture is measured at 605 nm after 30 s. By standard-additions recovery was 86 to 104%, the detection limit was 0.2 µg L-1 and the coefficient of variation (n = 5) was 0.6 to 1.1%. In determining 10 µg L-1 of iodide reducing organic materials interfered seriously. Sampling frequency was 90 runs h-1
Iodide Spectrophotometry

"Elimination Of Interferences In ICP-AES By Flow Injection Gradient Technique-generalized Standard Addition Method"
Gaodeng Xuexiao Huaxue Xuebao 1989 Volume 10, Issue 12 Pages 1185-1188
Luo Jianbo, Zhang Zhanxia, Qian Haowen, Cai Mingxiang

Abstract: A method based on a flow injection gradient technique (FIGT) and generalized standard addition method (GSAM) is developed for the elimination of matrix and/or spectral interferences in inductively coupled plasma atomic emission spectrometry (ICP-AES). Only one standard for an analyte is used to obtain the signals required for the evaluation in the GSAM. Operating parameters, including the carrier flow rates and residence times, are discussed in detail. To assess the proposed method, two synthetic samples, two types of Cu alloys and steel were analyzed for Zn, Mn, and As respectively. The relative standard deviations are 0.5-1.9%.
Zinc Manganese Arsenic Alloy Alloy Spectrophotometry

"Evaluation Of Three FIA Standard-addition Calibration Methods For ICP Spectroscopy"
Guangpuxue Yu Guangpu Fenxi 1990 Volume 10, Issue 2 Pages 49-53
Fan, S.;Fang, Z.L.

Abstract: Soil (0.2 to 0.5 g) is mixed with a few drops of water, 5 mL of HNO3 - HClO4 (3:1) and 3 mL of HF and then evaporated at 180°C to ~1 ml; 5 mL of 10% HCl is added to the residue which is then boiled. After cooling, the mixture is diluted with 10% HCl to 50 mL. Three methods used for analysis of the solution are those of Araujo (Anal. Chim. Acta, 1985, 17, 337), Tyson (Anal. Chim. Acta, 1983, 145, 159) and Fang (Anal. Chem., 1985, 57, 1457); procedures and diagrams of FIA systems are presented. Precision and recovery of these methods are compared, and their capabilities to compensating various matrix effects are detailed.
Environmental Sample preparation Spectrophotometry

"Determination Of Trace Mercury In Environmental And Biological Samples By Flow Injection Hydride-generation Graphite-furnace AAS"
Guangpuxue Yu Guangpu Fenxi 1993 Volume 13, Issue 5 Pages 107-110
Ma, Y.P.;Gulikezi;Fang, X.H.

Abstract: Pre-treated sample (500 µL) was injected and carried by a stream of water (6 ml/min) to react with streams of 5 M HCl and 0.3% KBH4 (both at 1 ml/min). After passing through a gas-liquid separator, the generated Hg was carried by Ar at 50-80 ml/min to a self-made Au-coated graphite-furnace for AAS, with pre-concentration and atomization temperature of 45-160°C and 500°C and 600°C, respectively. By standard-additions method, recovery was 98-101%; RSD were 5-10%. The calibration graph was linear with a detection limit of 20 pg of Hg. The method was applied to assay of human hair, urine, soil and peach leaf. No interference was observed from co-existing ions. Sampling rate was 50 runs per h.
Mercury Hair Environmental Urine Leaves Spectrophotometry

"Recent Development In Flow Injection Analysis"
Huaxue Tongbao 1984 Volume 47, Issue 8 Pages 22-24
Xu, S.K.;Fang, Z.L.

Abstract: A review is presented of recent sampling techniques, including flow-dynamics injection and standard-addition techniques for AAS and ICP-AES Step-wise techniques are also described, as applied to dilution, correction, titration, incremental sampling, stop - flow and fast-response determination, and scanning. (19 references).
Spectrophotometry Spectrophotometry

"Microprocessor-controlled Single Standard Flow Injection Analysis Spectrophotometry"
Huaxue Tongbao 1990 Volume 53, Issue 8 Pages 48-51
Fu, J.;Lin, G.;Yang, J.;Wang, Z.;Ma, C.

Abstract: Three calibration methods are described for the cited method. (i) A calibration graph of concentration. vs. delayed time was obtained by injecting a standard solution containing the components to be determined; this was applied in the determination of Mg with water as carrier, 0.012% chlorophosphonazo I in borax - NaOH (pH 10.5) as reagent solution and absorbance measurement at 580 nm. (ii) The standard additions method was used with a single standard solution and applied in the determination of Zn with water as carrier, 1.48% KCl in borax - NaOH (pH 9) as reagent solution and absorbance measurement at 620 nm. (iii) By using a graph of absorbance vs. time of single standard solution, a second calibration graph was constructed; this was applied in the determination of Fe(III) with water as carrier, 13% H2O2 in 0.164 M HCl and 0.0144 M Na diphenylamine sulfonate as reagent solution and absorbance measurement at 550 nm. Recoveries were quantitative and coefficient of variation ranged from 1.2 to 3.2%.
Zinc Magnesium Spectrophotometry

"SIRE-technology. 1. Amperometric Biosensor Based On Flow Injection Of The Recognition Element And Differential Measurements"
Instrum. Sci. Technol. 1998 Volume 26, Issue 1 Pages 45-57
D. Kriz; C. Berggren; A. Johansson; R. J. Ansell

Abstract: An amperometric biosensor with injection of the recognition element (SIRE) is described. An oxidase enzyme is injected into the measuring chamber, separated from the sample by a semi-permeable membrane. It is possible to make measurements in the presence and absence of enzyme and subtract the background current. This differential measuring technique has been difficult with previous sensors because it is very difficult to match two sensors. The versatility of the biosensor was demonstrated by determination of several different metabolites (glucose, lactate, Ph alanine, and galactose). The system was not optimized for the individual analytes, but showed a linear response for each up to approximately 10 mM. For glucose, a detection limit of approximately 2 µM was achieved. By using the differential measuring technique, glucose could be determined by direct measurement in a urine sample with the standard addition method. The repeatability was found to be lower than 3.7 % (n=5) over the range 0.3-5.0 mM for glucose, and the reproducibility better than 5 % (n=5). The biosensor showed no decrease in response at temps. up to 60°C and could easily be cleaned with a solution of hydrogen peroxide and by sweeping of the potential. Thus, this amperometric biosensor was found to have several advantages compared to conventional ones.
Glucose Lactate Phenylalanine Galactose Urine Amperometry Sensor

"Simultaneous Flow Injection Determination Of Diquat And Paraquat In Foodstuffs, Natural Waters And Biological Fluids"
Int. J. Environ. Anal. Chem. 1991 Volume 44, Issue 4 Pages 243-252
T. P&eacute;rez Ruiz; C. Martinez Lozano; V. Tom&aacute;s

Abstract: Sample (100 g) of pulped potato tubers was macerated with water and 18N-H2SO4 for ~3 min before refluxing for 5 h and filtration. Human serum (1 ml), was subjected to protein separation with sulfosalicylic acid before filtration. The filtrates and a diluted sample of synthetic urine were then analyzed for diquat (I) and paraquat (II) by the standard additions method in a dual-channel, dual-detector, flow injection system. Sample was split 1:4 (I:II) into two channels and I and I were merged (at 0.6 mL min-1) with streams of 0.1% sodium dithionite in 0.5 M borax buffer (pH 8) and 0.5% sodium dithionite in 0.5 M ammonia buffer (pH 9), respectively. I was then determined spectrofluorimetrically at 497 nm (excitation at 428 nm) and II was determined spectrophotometrically at 605 nm. The calibration graphs were rectilinear from 0.06 to 10 µg mL-1 of I and 0.2 to 20 µg mL-1 of II; detection limits were 7 µg L-1 for I and 36 µg L-1 for II. The analysis rate was 70 samples h-1. The method was applied to the determination of I and II in potable water.
Diquat Paraquat Blood Serum Food Water Environmental Urine Fluorescence Spectrophotometry

"Influence Of Some Parameters On Membrane Selectivity In Flow Injection Potentiometry"
Izv. Khim. 1990 Volume 23, Issue 2 Pages 167-171
Ilcheva, L.;Yanakiev, R.

Abstract: Selectivity coefficient >1 of commercial Cl--, Br-- and NO3--selective electrodes towards various interfering species in conventional potentiometry can be considerably improved if the electrodes are used as sensors in flow injection analysis. The selectivity can be further improved by increasing the carrier-stream flow rate, decreasing the injection volume, and use of the method of standard additions. The interference from 0.6 mM Br- was thereby overcome when determining ~0.1 to 0.2 M Cl- in seawater by the flow injection technique with a Cl--selective electrode.
Chloride Sea Electrode Potentiometry

"Trace Analysis Of Organothiophosphate Agricultural Chemicals By High Performance Liquid Chromatography-photolysis-electrochemical Detection"
J. Agric. Food Chem. 1984 Volume 32, Issue 3 Pages 622-628
Xiang Dong Ding and Ira S. Krull

Abstract: Organic thiophosphate agricultural chemicals, malathion, parathion and others, can be analyzed by the newer method of high performance liquid chromatography (HPLC) with online photolysis (hv), followed by electrochemical detection (EC) using single- or dual-electrode approaches for the species generated. This approach, HPLC-hv-EC, was applied to ~20 thiophosphates, most of which were widely used agriculturally and for which trace residue levels were routinely monitored. Dual-electrode response ratios were determined for all analytes, along with minimum detection limits (MDL) in many cases. These approaches were also used for the quality control evaluation of commercial formulations by flow injection analysis (FIA) with hv-EC and no HPLC separations. Wheat middling extracts were analyzed by the commonly used gas chromatography (GC) flame photometric detection (FPD) method of residue analysis, and by HPLC-hv-EC. These comparative studies indicate that the newer method was reproducible, accurate, precise and reliable. Standard additions were applied to wheat middling extracts, and the quantitative results were compared with the external standard method.
Malathion Parathion Wheat Electrochemical analysis

"Determination And Speciation Of Arsenic In Human Urine By Ion-exchange Chromatography - Flow Injection Analysis With Hydride Generation - Atomic Absorption Spectroscopy"
J. AOAC Int. 1994 Volume 77, Issue 2 Pages 441-445
Jimenez De Blas, O.;Vicente Gonzalez, S.;Seisdedos Rodriguez, R.;Hernandez Mendez, J.

Abstract: For the determination of total As in urine, the organic matter was oxidized by a mineralization procedure (Minoia et al., Med. Lavoro, 1978, 69, 681) before determination by FIA - hydride-generation AAS using a standard-additions method. Separation of metabolic forms of As was performed by cation-exchange on a column (20 m x 1 cm i.d.) of AG50W-X80 (H+ form; 100-200 mesh) washed with 0.5 M HCl. The urine sample was acidified with concentrated HCl before elution by gravity (~3 ml/min). The method was based on that previously described by Tam et al. (cf. Bull. Environ. Contam. Toxicol., 1979, 21, 371) and the fractions collected were analyzed for As species by FIA - hydride-generation AAS. The instrument used was a Model AA-1475 (Varian Analytical Instruments, Sunnyvale, CA, USA) with an air-acetylene flame and an hollow cathode lamp at 9 mA; As was detected at 193.7 nm (full operating conditions are listed). The detection limits were 2 ppb for each As form and 3 ppb for total As after mineralization of wine. Recoveries were 93, 91 and 85% for 10 ppb of inorganic As, 20 ppb of monomethylarsonic acid and 40 ppb of dimethylarsinic acid, respectively. RSD (n = 10) were 3.2-4.6%. The method can be used for studying exposure to As.
Arsenic Urine Wine Spectrophotometry

"Merging Zones Standard Addition Technique For Determination Of Copper In Beer By Flow Injection Atomic Absorption Spectrophotometry"
J. AOAC Int. 1998 Volume 81, Issue 3 Pages 645-647
S&iacute;lvia M.V. Fernandes, Ant&oacute;nio O.S.S. Rangel and Jos&eacute; L.F.C. Lima

Abstract: A flow injection system for determination of copper in beer by atomic absorption spectrophotometry by the standard additions method is described. The manifold, based on the merging zone technique, prevents the burner head from clogging, as observed with the conventional reference method. With 5 standard additions, results are comparable with those of the reference method. Relative deviations were less than 5.8%, precision was better than 6.4%, and sampling rate was about 30 samples/h. A less precise, less accurate, but faster procedure (75 samples/h) is possible with only 2 standard additions. The detection limit was 5 µg/L.
Copper Beer Spectrophotometry

"Ion-exchange Chromatographic Determination Of Hypoglycine A In Canned Ackee Fruit"
J. AOAC Int. 1989 Volume 72, Issue 2 Pages 374-377
Chase, G.W.;Landen, W.O.;Gelbaum, L.T.;Soliman, A.G.M.

Abstract: Canned ackee fruit were drained from the liquid medium and homogenized with aqueous 80% ethanol, the homogenate was centrifuged and the supernatant solution was mixed with trichloroacetic acid. The mixture was filtered and a 15 µL portion was analyzed on a Waters automatic amino-acid analyzer. fitted with a No. 80002 ion-exchange column (25 cm x 4.6 mm) operated at 62°C with Na acetate buffer solution (pH 7.4) - Na citrate buffer solution (pH 3.15) (7:3) as mobile phase (0.4 mL min-1) and post-column derivatization with ninhydrin at 120°C for detection at 436 and 546 nm. Calibration graphs were rectilinear from 4.8 (detection limit) to 73 µg mL-1 of hypoglycine A in the final solution Recoveries of standard additions to the fruit and liquid medium (analyzed similarly) were 103 and 102%, respectively.
Hypoglycine A Fruit HPIC Spectrophotometry

"Determination Of Glucose By Flow Injection Analysis With The Merging Zone Method"
J. Flow Injection Anal. 1987 Volume 4, Issue 1 Pages 4-14
Masako Tomoda, Daisuke Yoshizawa, Kazuhide Uchida, Kazuaki Fukushima and Shin-ichi Saito

Abstract: A 0.1 mL sample of, e.g., control serum and a 0.79 mL portion of mixed reagent solution containing aldose 1-epimerase, glucose oxidase, peroxidase, 4-aminoantipyrine and Na 3-(3,5-dimethoxyanilino)propanesulfonate are injected into separate carrier streams of phosphate buffer solution (pH 6.95) that is 0.15 M in NaCl and contains 0.6% of Triton X-100 (0.5 and 2 mL min-1, respectively). The zones merge and enter a reaction coil (15 m x 0.5 mm) maintained at 45°C, and the absorbance of the colored product is measured at 580 nm. The calibration graph is rectilinear for 0.18 mg mL-1 of glucose. Results for various control sera agreed with the reference values, and recoveries of standard additions to these sera were quantitative. (Cf. Uchida et al., Anal. Sci., 1987, 3, 181).
Glucose Blood Serum Clinical analysis Spectrophotometry

"Evaluation Of Flow Injection Sample To Standard Addition Method For The Inductively Coupled Plasma Mass Spectrometric Determination Of Aluminum In Biological Tissues"
J. Mass Spectrom. 1996 Volume 31, Issue 4 Pages 427-432
A. G. Coedo*, M. T. Dorado, J. Ruiz, M. Escudero, J. C. Rubio

Abstract: Tissues were minced, dried and powdered. Portions (0.5 g) were oxidized with 4 mL HNO3 in a microwave apparatus, with a 7-step heating programme. The solution was evaporated almost to dryness, mixed with a solution containing 1 µg Sc(III) (internal standard to compensate for plasma and ion signal instability) and diluted to 25 mL with 0.1% HNO3. Portions (0.5 ml) of this solution were injected into the carrier (2.8 ml/min) containing an Al(III) standard of 20 ng/ml and 40 ng/nl of Sc(III) in 0.1% HNO3 and this was followed by the injection of 0.5 mL of a digestion blank. The injection valve was located a few cm away from the cross-flow nebulizer and the ions 27Al and 45Sc were measured. The sample concentration then corresponded to the difference between the signals for the sample (maximum) and the blank (minimum). The method has the advantages of requiring less sample, being quicker and minimizing salt deposition on the sample and skimmer cones. Results for reference materials were similar to those obtained by conventional standard additions. Recovery of 0.5-10 ppm Al(III) was close to 100%. The detection limit was 10 ppb.
Aluminum(III) Biological tissue Mass spectrometry Sample preparation

"Simple Data Acquisition System For Fast Standard Additions Using Flow Injection Analysis"
Lab. Microcomput. 1990 Volume 9, Issue 2 Pages 44-49
Pasquini, C.;Arujo, M.C.U.;Bruns, R.E.

Abstract: Hardware and software are described for a system comprising of a single board microcomputer, an analogue to digital converter and AES or AAS. Serial data transfer to a personal computer for data analysis is possible.
Spectrophotometry Spectrophotometry

"Automated Nitrate Assay In Plant Material Following The Flow Injection Analysis Principle"
Landwirtsch. Forsch. 1985 Volume 38, Issue 1 Pages 99-104
Schwerdtfeger, E.

Abstract: Nitrate was determined in plant material by flow injection analysis with Cd reduction to nitrite and absorbance measurement at 540 nm. The relative standard deviation in the range 0.5-5.0 ppm was 1.6%, and the assay obeyed Beer's Law in the range 0.05-10 ppm. Matrix effects were minimized by the standard addition method. (SFS)
Nitrate Plant Vegetable Spectrophotometry

"Preparation Of Tubular Flow-through Scopolamine Electrode And Its Application In Flow Systems"
Lihua Jianyan, Huaxue Fence 1990 Volume 26, Issue 5 Pages 296-301
Cui, H.B.;Sun, J.Y.;Li, B.

Abstract: The cited electrode (illustrated) was prepared from a PVC tube (35 mm x 1 mm) with a middle perforation of 1.5-mm diameter covered with a membrane containing 1% hyoscine (I) - Na tetraphenylborate ion associate, 68% dibutyl phthalate and 31% PVC - AgCl-saturated 0.1 M NaCl - 10 mM I as filling solution The electrode was installed into a flow injection analyzer. and applied in the analysis of injection solution A portion of solution was diluted with 0.05 M Mg acetate and injected into a carrier stream of 0.05 M Mg acetate (1.5 mL min-1) to the detector for measurement. By standard-additions method, recovery was 99 to 101% and coefficient of variation was 0.5%. Determination is at ppm-level. The results obtained compared well with those of the Chin. P. method.
Scopolamine Electrode Electrode Electrode

"Flow Injection Analysis - Spectrophotometric Determination Of Calcium In Blood Serum"
Lihua Jianyan, Huaxue Fence 1992 Volume 28, Issue 4 Pages 218-220
Fan, S.;Fang, Z.L.

Abstract: Serum (0.5 µL) is diluted with water to 25 mL and a 35 µL portion of the solution is injected into the analyzer. (diagram given) to flow with a carrier stream of water (1.1 mL min-1) to react with a mixture produced from a chromogenic reagent stream (made of 40 mL of 10 mM hexadecyltrimethylammonium bromide, 40 mL of 2 mM xylenol orange, 10 mL of 2.5% 8-hydroxyquinoline and water to 500 ml; at 2.5 mL min-1) and NH3 - NH4Cl buffer of pH 10.5 (at 0.8 mL min-1) in a reaction tube (95 cm x 0.8 mm). Detection is at 610 nm by standard-additions method; average recovery is 96.3% and coefficient of variation (n = 10) is 1.6%. Interferring Mg is overcome. Determination is at µg mL-1-level. Results are satisfactory and comparable with those obtained by ICP.
Calcium Blood Serum Spectrophotometry

"Direct Steady Temperature Platform GFAAS Determination Of Micro Amounts Of Lead In Grape Wine By The Steps Ramp Procedure"
Lihua Jianyan, Huaxue Fence 1996 Volume 32, Issue 2 Pages 86-88
Sun Xiaojuan

Abstract: Sample was treated with dilute HNO3 to a final HNO3 concentration of 0.2% and dilution of 1:2 or 1:3. Portions (10 µL) of the solution were mixed with 10 µL 2.5% NH4H2PO4 and the mixture was loaded by an automatic sampler onto the L'vov platform in the graphite tube for AAS. The injection temperature was 50°C and the ramp procedure was carried out with drying at 80°C (slope of 1 s; maintained for 15 s) as well as 120°C (slope 25 s; for 10 s), and ashing at 450°C (slope 10 s; for 10 s) as well as 700°C (slope 10 s; for 15 s), with Ar flow-rate 300 ml/min, and atomization at 1800°C (gas flow stopped). The atomization signal appeared as single peak. There was no matrix interference using both HNO3 and NH4H2PO4 as matrix modifiers. By standard-additions method, recoveries were 97-104% with RSD of 0.8-3.9%. Results were compared with those obtained by FIA.
Lead Wine Spectrophotometry

"Determination Of Copper In Electrolyte By The Automatic Standard Addition Method"
Lihua Jianyan, Huaxue Fence 1997 Volume 33, Issue 4 Pages 172-173
Xiao, C.L.;Tan, A.M.

Abstract: Sample (30 µl), or portions of standard 0.2 g/l Cu solution, were analyzed by injection into the carrier stream of 50 m/l sodium acetate/50% acetic acid buffer of pH 3 (buffer A), of a flow injection manifold (schematic shown) and mixed with 10 mL 0.04% thio-Michler's ketone in DMF/6% ascorbic acid/buffer A (1:2:3) and the absorbance was measured at 560 nm. The calibration graph was linear up to 1.5 g/l Cu. Only Ni interfered. The analysis rate was 20/h. The results were compared with those obtained by iodimetry.
Copper Spectrophotometry

"Simultaneous Determination Of Iron And Aluminum With Flow Injection-standard Addition Dual Wavelength Spectrophotometry"
Lihua Jianyan, Huaxue Fence 1998 Volume 34, Issue 5 Pages 195-197
Qu Xiangjin,Zhou Jie, Sun Yanhua, Zhang Changjun

Abstract: A method for the simultaneous determination of Fe and Al with CAS (Chrome Azurol S) as chromogenic reagent in the presence of CTMAB by FIA standard addition DW-spectrophotometry was presented. The chromogenic reaction of CAS with Fe or Al was carried out in pH 6.75 NH4AcO buffer solution The determining wavelength pairs were: Fe, 629 nm and 587 nm, and Al, 612 nm and 646 nm. Under optimum conditions, the detection limits were: Fe, 0.001 µg mL-1, and Al, 0.002 µg mL-1, and Beer's law was obeyed at Fe, 0-1.2 µg mL-1, and Al, 0-0.8 µg mL-1. The recoveries were: Fe, 98.6-102.0%, and Al, 98.1-100.4%. The sampling rate of the FIA system was 60 samples per h. The interference of Cu(II) can be masked by thiourea. The method was applied to determine Fe and Al in Cu alloys with relative standard deviation: Fe, 0.30-0.41%, and Al, 0.15-1.1%.
Iron Aluminum Alloy Spectrophotometry

"Determination Of Hydrogen Peroxide In Rain-water By Flow Injection Analysis With Titanium(IV) - 4-(2-pyridylazo)resorcinol Reagent"
Nippon Kagaku Kaishi 1991 Volume 1991, Issue 5 Pages 430-432
Matsubara, C.;Sakai, K.;Takamura, K.

Abstract: A 100 µL sample is flow-injected into a carrier stream of water to the pre-column filled with Amberlite IR-120B before mixing with 0.24 mM Ti - 4-(2-pyridylazo)resorcinol (I) reagent (pH 2.1) and with 0.1 M ammonium buffer of pH 10.7; both mixing coils (130 cm x 0.5 mm) were heated in a thermostat bath at 60°C (all flow-rates were 0.2 mL min-1). Spectrophotometric detection of Ti(IV) - I - H2O2 was by measurement at 508 nm (ε = 36,000). By standard-additions method, recovery was 95.9 to 101.4% and coefficient of variation was 0.8%. Determination range was 1.36 (detection limit) to 1360 ppb of H2O2.
Hydrogen peroxide Rain Spectrophotometry

"Hydrogen Peroxide Determination In Estuarine And Marine Waters By Flow Injection With Fluorescence Detection"
Oceanol. Acta 1995 Volume 18, Issue 3 Pages 353-361
Amouroux D, Donard Ofx

Abstract: The Scopoletin-Peroxidase fluorescence decay method has been developed using standard additions and a flow injection manifold for hydrogen peroxide (H2O2) determination in marine waters. The limit of detection of the method was optimized using stored milli-Q water with a minimum of 5 nM (3s). The method was found to be linear from 5 to 700 nM, with an approximate relative standard deviation of 10%. This accuracy was verified on both milli-Q and natural waters running systematically duplicate analysis. (35 References)
Hydrogen peroxide Estuarine Sea Fluorescence

"Determination Of Iron And Copper In Infant Formula Powdered Milks By Flow Injection Atomic Absorption Spectrometry"
Quim. Anal. 1987 Volume 6, Issue 4 Pages 427-435
Burguera, M.;Burguera, J.L.;Garaboto, A.M.;Alarcon, O.M.

Abstract: The sample was dissolved in water (10 mL per 1 g), and a 3 mL portion of the solution was mixed with 1 mL of concentrated HNO3 and 1 mL of water, and heated in a 50 mL phial in a 700-W microwave oven for 5 min. The product was dispersed in 1 mL of 100% Triton X-100 and diluted to 5 mL with water. Portions (100 µL) were injected into a carrier stream of water (2.9 mL min-1 for Fe; 3.7 mL min-1 for Cu) flowing to a nebulizer for AAS in an air - acetylene flame; measurements were made at 248.3 and 324.8 nm for Fe and Cu, respectively. As some other ions interfered, the method of standard additions was used for evaluation. Results agreed with those obtained by conventional AAS, colorimetry and ring colorimetry. The detection limits were 0.02 and 0.01 mg L-1 for Fe and Cu, respectively, and the coefficient of variation was ~5% for 0.38 mg L-1 of Fe or 0.19 mg L-1 of Cu.
Copper Iron Baby Powder Spectrophotometry

"Determination Of Trace Arsenic And Mercury In Drink By Hydride Generation-ICP-AES"
Sichuan Daxue Xuebao (Ziran Kexue Ban) 1996 Volume 33, Issue 4 Pages 419-423
Hu, M.;Huang, Q.;Xia, H.;Tong, S.

Abstract: A method for simultaneous determination of trace concentrations of As and Hg in drink have been investigated by continuous-flow mode hydride generation and inductively coupled plasma atomic emission spectrometry. The influence of operating conditions on the result of analysis is discussed. The proposed method is sensitive, accurate and easy to operate. The relative standard deviation is less than 5% if the concentration is 0.05-0.1 mg/L. The recovery of standard addition is 87-100%.
Arsenic Mercury Beverage Spectrophotometry

"Automated Determination Of Nitrate And Nitrite By Flow Injection Analysis"
Voeding. Tech. 1995 Volume 28, Issue 4 Pages 11-14
Klomp, H.;Ellen, G.;De Jong, E.A.M.

Abstract: Application of a Tecator FIA (flow injection analysis) method to determine nitrate and nitrate in milk products is discussed. Trials showed that this method permits easy, rapid and accurate analysis of nitrate and nitrite. Determination of low nitrite concentrations in cheese and baby foods requires some method modifications to achieve sufficient sensitivity. Using the modified method, the detection limit for nitrite in cheese is 0.1 mg/kg. In dried products with a high content of lactose or other compounds which pass through the dialysis membrane, a systematic positive error may occur of the order of 0.05-0.1 mg/kg product; the detection limit is therefore matrix-dependent. Recoveries of nitrate and nitrite (determined by the method of standard additions) are 95-100% for most products. For nitrate concentrations of 10 mg/kg DM and nitrite concentrations of 0.5 mg/kg DM, relative s.d. are approximately 5%.
Nitrate Nitrite Milk Product Food Baby

"Performance Of An FIA - Flame AAS System Using An Electromagnetic Valve As Sampler"
Yankuang Ceshi 1989 Volume 8, Issue 4 Pages 300-303
Xu, P.;Hou, X.;Zhou, X.;Yan, D.

Abstract: A FIA - flame AAS apparatus with an electromagnetic valve as sampler is described. Factors influencing the dispersion and sampling frequency of the FIA as well as the precision of the whole system were investigated, e.g., the sampling volume, velocity of carrier flow and length of reaction circle. The system has been used in the determination of Li in brine by the standard-addition method and in the determination of Pd in geological samples after mercaptobenzothiazole - methylisobutyl ketone extraction.
Lithium Palladium Environmental Geological Spectrophotometry

"Design And Application Of A Micro-versatile Phase Separator For Continuous Liquid-liquid Extraction. 2. Analytical Performance Of Flow Injection Solvent Extraction Spectrophotometry For The Determination Of Iodide"
Yankuang Ceshi 1998 Volume 17, Issue 1 Pages 29-32
Lin Shoulin, Zheng Qunxiong

Abstract: A glass gravity separator for continuous liq.-liq. extraction system was developed and used for the determination of trace iodide ion by online extraction-spectrophotometry. The separator provides several advantages over the existing ones reported in the literatures. The flow ratio of aqueous mobile phase to organic mobile phase (.upsilon.aq:.upsilon.org) is 30. The linear range for I- is 0-3.000 mg/L with detection limit of 70 µg/L. A precision of 2.2% relative standard deviation (1 mg/L of I-, .eta.=7) and a sample throughput of 25/h were obtained. The method was applied to the determination of I- in kelp with standard addition recovery of 98%.
Iodide Plant Spectrophotometry

"Ionometric Determination Of Thiocyanate By The Method Of Additions In Continuous-flow Analysis"
J. Anal. Chem. 1992 Volume 47, Issue 4 Pages 608-612
Evsevleeva, L.G.;Urusov, Y.I.;Petrukhin, O.M.;Borzitsky, Y.A.

Abstract: Continuous-flow analysis measurements were made with a SCN--selective electrode composed of a membrane prepared from PVC powder (0.1 g), dibutyl phthalate (0.3 ml), tetradecylammonium thiocyanate (40 mg) and THF (6 ml). The electrode was calibrated against a standard KSCN solution. The parallel addition method was used; a single measurement took ~8 s. A method has been developed for the determination of SCN- ions by standard addition in continuous-flow. The anal. output is 420 measurements per h. The reproducibility is 0.3 mV. The method was applied to the determination of SCN- in model sample and Ag-plating solution
Thiocyanate ion Silver Electrode