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

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Classification: Industrial

Citations 64

"Repetitive Determinations Of Iron(III) In Closed Flow-through Systems By Series Reactions"
Anal. Chim. Acta 1977 Volume 94, Issue 2 Pages 289-296
V. V. S. Eswara Dutt, Daniel Scheeler and Horacio A. Mottola

Abstract: The determination of iron(III) with thiocyanate by means of sample injection into a chamber in a closed loop system of circulating reagent is described. Restitution of the absorbance to baseline by ligand exchange and by a redox process in the presence of iodide is discussed, together with some kinetic aspects of the decolorization reaction responsible for the return to the baseline. The iron content of the samples is deduced from the height of the generated transient signal, which is directly proportional to the iron(III) content. As many as 350 determinations/h can be processed when ligand exchange is used and 120/h when iodide is used for baseline restitution. Sample injection techniques of this type are particularly useful in industrial processes and quality control, and environmental monitoring, since they result in a decrease in operating cost and time.
Iron(III) Spectrophotometry Closed loop Redox Kinetic

"Determination Of Water By Flow Injection Analysis With The Karl Fischer Reagent"
Anal. Chim. Acta 1980 Volume 114, Issue 1 Pages 199-208
Ingrid Kågevall, Ove Åström and Anders Cedergren

Abstract: A method for the determination of water in organic solvents by flow-injection analysis (f.i.a.) is described. The method, which is based on the reaction between water and the Karl Fischer reagent, is capable of 120 determinations per hour. The concentration range 0.01-5% (v/v) of water can be covered by using a single Karl Fischer reagent solution. The results obtained with a specially constructed potentiometric detector showed a relative standard deviation of less than 0.5% (v/v). This value was about 3 times less than that obtained with a spectrophotometric detector. The f.i.a. technique is shown to offer some unique possibilities in minimizing interferences associated with the standard Karl Fischer batch titration method.
Water Karl Fischer analysis Potentiometry Titrations

"Minimization Of Interference Effects From Iodine-consuming Samples In The Determination Of Water With The Karl Fischer Reagent In A Flow Injection System"
Anal. Chim. Acta 1981 Volume 132, Issue 1 Pages 215-218
Ingrid Kågevall, Ove Åström and Anders Cedergren

Abstract: A principal feature of the flow-injection approach for determination of water with the Karl Fischer reagent is the small influence of side reactions. This is confirmed by the determination of water in an iodine-consuming sample, penicillin (fugacillin).
Water Karl Fischer analysis Spectrophotometry Interferences Titrations

"Online Monitoring With An Ion-selective Electrode In A High-volume Flow-through Cell"
Anal. Chim. Acta 1982 Volume 136, Issue 1 Pages 51-59
A. M. Bond, H. A. Hudson, P. A. Van Den Bosch and F. L. Walter, H. R. A. Exelby

Abstract: A high-capacity poly(vinyl chloride) flow-through cell which can be used at a flow rate of 3000 mL min-1 in a corrosive environment is described for the continuous on-line monitoring of copper ions in plant electrolytes. The copper(II) ion-selective electrode and double-junction reference electrode in the cell are coupled to a voltmeter and microprocessor-controlled instrumentation to achieve on-line monitoring. The system is designed to withstand the severe industrial environments and was field-tested in a copper refinery where continuous monitoring of copper is required. Cell design and results of the investigation on the determination of copper in plant electrolytes are described.
Copper Electrode Computer

"Spectrophotometric Determination Of Sulfate In Sodium Hydroxide Solutions By Flow Injection Analysis"
Anal. Chim. Acta 1984 Volume 156, Issue 1 Pages 313-317
E. A. Jones

Abstract: The method is based on the catalytic effect of SO42- on the reaction between Zr and methylthymol blue(I). Under optimum conditions, the test solution (100 µL) is injected into a stream of 80 µM-I in 0.6 M HCl (1.2 mL min-1), which is then mixed with 800 µM-ZrOCl2 in 50 mM HCl (1.2 mL min-1). The mixture is passed through a 4-m reaction coil and the absorbance of the resulting complex is monitored at 586 nm (e = 20,000). The calibration graph is rectilinear for 0.05 to 0.5 g L-1 of SO42-, with a coefficient of variation of ~2%. Results for 10 batches of 1 M sodium hydroxide agreed well with those obtained by ion chromatography and by gravimetry. Twenty samples can be analyzed per h.
Sulfate Spectrophotometry Catalysis Optimization

"Flow Injection Analysis With Tensammetric Detection For The Determination Of Detergents"
Anal. Chim. Acta 1984 Volume 156, Issue 1 Pages 71-76
M. Bos, J. H. H. G. van Willigen and W. E. van der Linden

Abstract: The sample (60 µL of, e.g., aqueous production-control solution or sewage) is injected into a carrier stream (5 mM in a surfactant), which is subsequently mixed with 0.1 M Na2SO4 and passed into a detector cell equipped with a mercury-coated gold electrode, an uncoated gold counter-electrode and a silver - AgCl reference electrode. The change in capacitance of the electrical double layer of the working electrode is measured at -0.85 V (except for benzalkonium chloride, for which the applied potential is -0.40 V). Calibration graphs are non-linear and are best approximated by use of polynomial or cubic spline functions. The method is applicable to both ionic and non-ionic surfactants in the range 10 to 100 µM, with relative errors of ~±4%. Sixty samples can be analyzed in 1 h.
Benzalkonium chloride Surfactants Electrode Electrode Sensor Voltammetry

"Determination Of Iodine Value Of Fatty Acids By A Flow Injection Method"
Anal. Chim. Acta 1984 Volume 158, Issue 2 Pages 157-167
Cheng-chih Lee and Bruce D. Pollard

Abstract: A modification of the standard Wij solution method was used in an automated system controlled by an AIM-65 microcomputer. Iodine values of various industrial fatty acids were determined. Optimum operating conditions were established for the system, and a comparison was made between detection by u.v. absorbance and potentiometry. The coefficient of variation between observed and expected values were 9% for u.v. absorbance detection and 0.9% with potentiometric detection. Results obtained were similar to those of the conventional method. The max. continuous-run sample through-put was 12 h-1.
Iodine value Potentiometry Spectrophotometry Method comparison Optimization

"Determination Of Lead In Gasoline By A Flow Injection Technique With Atomic Absorption Spectrometric Detection"
Anal. Chim. Acta 1986 Volume 179, Issue 1 Pages 491-496
Colin G. Taylor and John M. Trevaskis

Abstract: The organic lead compound is oxidized with iodine (3% in toluene) and the product is diluted with a solution of 1% of Aliquat 336 (methyltrioctylammonium chloride) in isobutyl methyl ketone. This solution is injected into a carrier stream of acetone for aspiration into the air - acetylene flame for measurement at 283.3 nm. The response is rectilinear for up to 16 mg L-1 with a limit of detection of 0.1 mg l-1. The standard deviation is between 2 and 5 mg L-1 for gasoline containing between 328 and 384 mg L-1 (n = 4). The results agree closely with those obtained by AAS and titrimetry.
tetraalkyllead Spectrophotometry Method comparison

"Online Application Of Ion Chromatography In A Thermal Power Plant"
Anal. Chim. Acta 1986 Volume 179, Issue 1 Pages 419-425
L. Balconi, R. Pascali and F. Sigon

Abstract: Complete monitoring of the 'condensate-feedwater' cycle in power plants requires reliable automatic methods suitable for very low concentrations of various chemical species. A complete on-line ion-chromatography monitoring system is under development. It comprises an automatic on-line sampling system two Dionex Model QUIC (process instrument) ion chromatographs, an on-line calibration systems, and a data acquisition/processing system. The present model serves for the determination of sodium, chloride and sulfate ions. Detection limits are < 1 µg L-1 (P = 95%) with linear ranges up to 10 µg L-1 or about 200 µg L-1 depending on settings. The importance of statistical evaluation of data is emphasized. The instrumentation was tested for sequential samples from crucial points of a 320 MW thermal power station with satisfactory results. Problems of reliability are discussed.
Chloride Sodium Sulfate HPIC

"Use Of Ion-selective Electrodes In Industrial Flow Analysis"
Anal. Chim. Acta 1986 Volume 185, Issue 1 Pages 171-178
Petr Pet&aacute;k, Karel Stul&iacute;k

Abstract: Two detector cells for use in such analyzes involving flow injection and continuous-monitoring techniques were tested; e.g., a cell with a CN--selective working electrode, a reference SCE and a variable volume of 25, 100 or 1500 µL was used to determine 5 to 50 mg L-1 of CN- in 70 µL samples injected into a carrier stream of aqueous NaOH (pH 11.5). The detection limit was 80 µg L-1 of CN-. When 50 samples of 1 mM CN- were injected periodically into a continuous carrier stream over several days the coefficient of variation was 2.5%. The 1500 µL cell was sensitive and gave reproducible results when the carrier solution flow rate was sufficiently high, e.g., 180 µL s-1. For continuous monitoring, large cell volume were advantageous as the signal approached that obtained under steady-state conditions, but senstivity was very poor and the response was sluggish when the cells were used with a Ca(II)-selective electrode and an NH3 gas probe.
Ammonia Calcium Cyanide Electrode Electrode Electrode Potentiometry Process control Sensitivity

"Flow Injection Analysis - A Survey Of Its Potential For Continuous Monitoring Of Industrial Processes"
Anal. Chim. Acta 1986 Volume 190, Issue 1 Pages 155-163
Jaromir Rika,

Abstract: A review is presented, with 18 references, including sample and reagent injection into reagent and sample streams, respectively, sample/reagent mixing and peak-height and peak-width measurements.

"Industrial Process Control By Flow Injection Analysis"
Anal. Chim. Acta 1986 Volume 190, Issue 1 Pages 165-176
M. Gisin and C. Thommen

Abstract: The principle of physiochemical and chemical modulation in flow injection analysis is outlined. Advantageous properties of flow injection analyzers for chemical on-line process control are summarized. Three exampls of applications are presented. First, peak-width measurements enable chemical batch processes to be monitored over several orders of magnitude of analyte concentration whereas peak-height measurements are selected in the critical state of the process where very small changes of analyte concentration must be determined precisely. Secondly, exploitation of variable gradient dilution to match sample concentration to the needs of accurate analysis is combined with trapped-zone selective spectrophotometry. Finally, frequency-discriminated chemical analysis is feasible by combining sample gradient formation with reagent injection.
Review Process control

"Flow Injection System For The Amperometric Determination Of Xylose And Xylulose With Co-immobilized Enzymes And A Modified Electrode"
Anal. Chim. Acta 1988 Volume 213, Issue 1-2 Pages 139-150
E. Dominguez and B. Hahn-H&auml;gerdal, G. Marko-Varga and L. Gorton

Abstract: A purpose-built flow injection analysis system was constructed that incorporated a 25 µL reactor containing xylose isomerase (omitted in determination of xylose alone), aldose 1-epimerase and glucose dehydrogenase immobilized on CPG-10 glass beads (37 to 74 µm diameter; 51.5 nm pore size). The NADH produced from NAD+ incorporated in the carrier solution [0.1 M phosphate buffer (pH 7.0) containing Mg] was detected electrochemically with use of a dye-modified graphite electrode in a wall-jet configuration (cf. Appleqvist et al., Anal. Abstr., 1985, 47, 12D151). Up to 30 determinations per hour were possible and calibration graphs were rectilinear for up to 2 mM xylose or -xylulose.
Xylose Xylulose Amperometry Electrode Sample preparation Controlled pore glass Extraction Immobilized enzyme

"Flow Injection Method For The Amperometric Determination Of L-lactate With Immobilized Enzymes And A Chemically Modified Electrode"
Anal. Chim. Acta 1988 Volume 213, Issue 1-2 Pages 91-100
L. Gorton and A. Hedlund

Abstract: The flow injection system included a packed-bed enzyme reactor containing L-lactate dehydrogenase and alanine aminotransferase co-immobilized on to glutaraldehyde-activated porous silica, where the L-lactate was oxidized to pyruvate in the presence of glutamate and NAD+, the latter being converted into NADH. The NADH formed was measured with use of a graphite electrode modified with Meldola blue (C. I. Basic Blue 6) and operated at 0 mV vs. Ag - AgCl (0.1 M KCl) in presence of a Pt-wire auxiliary electrode. The calibration graph was rectilinear for 10 µM to 3 mM NADH (10 µM to 1.5 mM lactate). Operating conditions were optimized and the results are discussed; common constituents of biological fluids and food industrial liquids are not expected to interfere electrochemically.
l-Lactate Electrode Electrode Amperometry Immobilized enzyme Interferences Reactor Optimization

"Voltammetric Information From Arrays Of Individually Controlled Electrodes - Their Potential For Industrial Process Measurements"
Anal. Chim. Acta 1993 Volume 273, Issue 1-2 Pages 111-121
P. R. Fielden* and T. McCreedy

Abstract: The construction, control and operation of an array of electrodes used to obtain voltammetric information in a wall-jet geometry is described for flow-stream analysis. The array consisted of a ring-disk arrangement, where the ring is composed of eight radially-spaced 1-mm glassy carbon disks. The ring array surrounds a 3 mm glassy carbon disk in the centre, impinged by a perpendicular 0.3 mm inlet diameter jet. Independent electrode control and monitoring were achieved through a computer-based multi-electrode potentiostat, designed to operate with single reference and counter electrodes. The flow cell was characterized through variation of the inlet jet separation from the planar ring-disk array and control of inlet volume flow-rate. Optimum conditions were chosen with stability as the primary criterion. A jet separation of 7.25 mm and a flow-rate of 1.5 mL min-1 ensured wall jet behavior at the central electrode and planar behavior at the ring array. These conditions were maintained throughout subsequent experiments which demonstrated the feasibility of utilizing the array of electrodes for voltammetric monitoring of simple mixtures of metal ions, with or without prior separation. The potential of this approach for industrial process monitoring is discussed with a view of maximizing information recovery and enhancing data reliability.
Voltammetry Electrode Process control

"Industrial Online Monitoring Of Penicillin V, Glucose And Ethanol Using A Split-flow Modified Thermal Biosensor"
Anal. Chim. Acta 1993 Volume 281, Issue 3 Pages 521-526
M. Rank, J. Gram, B. Danielsson

Abstract: Bioreactor fermentation broth was sampled online with a hydrophilized polypropylene filtration probe (Advanced Biotechnology, Puchheim, Germany) and pumped into an enzyme thermistor with a split-flow biosensor comprising a column of β-lactamase, penicillin V acylase, glucose oxidase/catalase or alcohol oxidase immobilized onto controlled-pore glass using γ-aminopropyltriethoxysilane and glutaraldehyde (details given), and a parallel reference column without enzyme. Columns were eluted (0.9 ml/min) with 0.1 M phosphate buffer of pH 7 containing 4 mM NaN3 or 5 g/l of benzoic acid (for the glucose oxidase/catalase column). The difference between the enthalpy changes on the two columns was monitored, amplified and processed by computer. The calibration graph for the penicillin V acylase column was linear from 0.5-150 mM penicillin V (20-500 µL samples); the determinations of penicillin V, penicilloic acid and p-hydroxypenicillin V agreed well with those obtained by LC. The β-lactamase column values were 10% higher than those obtained by LC. Results for ethanol (alcohol oxidase column) agreed with those obtained by GC.
Penicillin V Glucose Ethanol Enthalpimetry Sensor Thermistor Biotechnology Controlled pore glass Immobilized enzyme

"Ion Chromatography For Monitoring Biotechnological Processes. 2. Applications For Industrial Cultivation Media"
Anal. Chim. Acta 1994 Volume 286, Issue 2 Pages 179-187
Ute Scheller, Detlef Siedenberg, Uwe H&uuml;bner, Michael Siebold, Gerlinde Kretzmer and Karl Sch&uuml;gerl*

Abstract: The production of alkaline protease by Bacillus licheniformis, and the cultivation of Cephalosporium acremonium was monitored by the ion-chromatography of chloride, phosphate and sulfate anions in the broth. Sample proteins were filtered, and filtrates analyzed on a Hamilton PRP-X 100 ion-exchange column with a Hamilton PRX- x 100 pre-column and RI detection (no other details given). Lactic acid, acetic acid, citric acid and glucose, present during the production of lactic acid by Lactobacillus salivarius subsp. salivarius were also monitored by ion-exclusion chromatography (no details given). Glucose and lactic acid results compared favourably with those obtained by an enzyme FIA method using immobilized glucose oxidase and lactate oxidase amperometric detectors (no details given). The problems involved in sampling, sample pre-treatment, the optimization of the chromatographic analysis and the enrichment of the analytes after dialysis are discussed.
Lactic acid Acetic acid Citric acid Glucose HPIC Biotechnology Dialysis Optimization

"Flow Injection Analysis With Bulk Extraction Based Optical Sensor Membranes"
Anal. Chim. Acta 1994 Volume 294, Issue 1 Pages 49-56
Peter C. Hauser* and J. Christopher Litten

Abstract: A review is presented of some applications of optical sensing membranes as solid-phase photometric detectors in inorganic FIA. The membranes contain one or more selective ionophores or lipophilic pH indicators in a PVC matrix. Examples of test applications to determinations of Ca, K, Zn, ammonium and nitrate are described and commended as alternatives to flow injection potentiometry, with simpler operation and similar selectivities and detection limits. Light-emitting diode-photodiode transducer detectors were used. (28 references).
Calcium Potassium Zinc Ammonium Nitrate Electrode Spectrophotometry Potentiometry Sample preparation Sensor Review Photodiode Extraction

"Development Of Enzyme-cartridge Flow Injection Analysis For Industrial Process Monitoring. 1. Development And Characterization"
Anal. Chim. Acta 1994 Volume 298, Issue 2 Pages 141-149
H. J&uuml;rgens, R. Kabu&szlig;, T. Plumbaum, B. Weigel, G. Kretzmer, K. Sch&uuml;gerl, K. Andres, E. Ignatzek and F. Giffhorn

Abstract: The preparation of cartridges with five different enzymes: glucose oxidase (GOD), pyranose oxidase (PyOD), alcohol oxidase (AOD), L-amino acid oxidase (L-ASOD) and L-lactate-2-monooxigenase (LMO) immobilized on VA-Epoxy Biosynth carrier were optimized and standardized. The enzyme cartridges were characterized, integrated in flow injection analysis (FIA) systems and the optimal application conditions and salt effects were evaluated.
Process monitoring Immobilized enzyme

"Development Of Enzyme-cartridge Flow Injection Analysis For Industrial Process Monitoring. 2. Application For Monitoring Of Micro-organism Cultivations"
Anal. Chim. Acta 1995 Volume 302, Issue 2-3 Pages 289-296
H. J&uuml;rgens, L. Brandes, R. Joppien, M. Sieboldb J. Schubert, X. Wu, G. Kretzmer and K. Sch&uuml;gerl*

Abstract: Cartridges (1 ml) were filled with 200 mg of VA-Epoxy-Biosynthe E3 (Riedel-de Haen) on which glucose oxidase, alcohol oxidase, pyranose oxidase, L-amino acid oxidase or L-lactate monooxidase had been immobilized from phosphate buffer medium. Up to four enzyme cartridges were used in series or parallel for FIA of glucose, ethanol, L-amino-acids and lactate on Eppendorf instruments. Conditions are given for determining glucose and ethanol in Saccharomyces cerevisiae cultures, amino-acids during the production of fusion protein by recombinant Escherichia coli, and L-lactate during the production of lactic acid by Lactobacillus salivarius. The cartridges showed good long-term stability and response times of a few minutes.
Ethanol Glucose Amino acids, L Lactate Immobilized enzyme Process monitoring

"Determination Of Vanadium(IV) And Vanadium(V) By Formation Of A Transient Mixed Valence Complex In A Flow Injection Manifold"
Anal. Chim. Acta 1995 Volume 307, Issue 1 Pages 1-13
M. J. C. Taylor* and J. F. van Staden

Abstract: FIA systems are described for the determination of V(V) in the stripping and raffinate liquors from a solvent-extraction plant producing high-purity ammonium metavanadate and V(IV) in aqueous alkaline scrubbing solution used to remove H2S from sour gas streams. Both systems were based on the spectrophotometric determination of the V(IV)-V(V) complex at 630 nm and used a simple single-line manifold. For V(V) a sample (40 µL) was injected into a carrier stream (0.8 ml/min) containing 0.6 M ascorbic acid and 0.9 M H2SO4 then passed through a reaction coil (25 cm x 0.5 mm i.d.) and passed to the detector cell. For V(IV) a sample (50 µL) was injected into a similar carrier stream containing 1 g/l V(V) and 0.25 M NaSCN in 0.2 M phthalate buffer at pH 5.5 and passed through a reaction coil (50 cm x 0.5 mm i.d.). Detection was at 630 nm. Calibration graphs were linear for 0.5-60 g/l V(V) and 0.1-1 g/l V(IV). RSD were 0.02% (n=20) and 0.007% (n=10) for V(V) and V(IV), respectively, with sampling frequencies of 60 samples/h and 80 samples/h.
Vanadium(IV) Vanadium(V) Spectrophotometry Complexation

"Differential Flow Injection Potentiometry"
Anal. Chim. Acta 1995 Volume 311, Issue 2 Pages 175-181
Ivelin Rizov* and Liliana Ilcheva

Abstract: Flow injection potentiometric methods using two different ISE placed in series are described for the simultaneous determination of (i) nitrate and chloride and (ii) nitrate and ammonium. The flow injection manifold for the determination of nitrate and chloride consisted of a nitrate ISE separated from a chloride ISE by a reaction coil of 254 cm x 0.51 mm i.d. A sample volume of 60 µL was injected into a 0.04 M Na2SO4 carrier stream (6.3 ml/min). The nitrate concentration was determined using the chloride ISE as a reference electrode and vice versa. The RSD (n = 13) for the determination of 0.1 mM nitrate and 1 mM chloride were 1.1 and 0.9%, respectively. A similar manifold is described for the determination of nitrate and ammonium using nitrate and ammonium ISE separated by a reaction coil of 284 cm x 0.51 mm i.d. The RSD (n = 12) for the determination of nitrate and ammonium in waste water from a urea production plant were 1.1 and 0.9%, respectively.
Ammonium Chloride Nitrate Electrode Electrode Electrode Potentiometry Dual detection

"Development Of Enzyme-cartridge Flow Injection Analysis For Industrial Process Monitoring. 3. Application For Monitoring Of Recombinant Animal Cell Cultivations"
Anal. Chim. Acta 1995 Volume 315, Issue 1-2 Pages 153-157
H. J&uuml;rgensb, R. Akhnoukha, G. Kretzmera and K. Sch&uuml;gerla,*

Abstract: The application of L-amino acid oxidase (L-ASOD) for monitoring of amino acids during the cultivation of the recombinant insect cell line, Spodoptera frugiperda, and the production of β-galactosidase as well as the application of L-lactate monooxidase (L-LMO) for the monitoring of the lactate concentration during the cultivation of the adherent recombinant cell line, Baby Hamster Kidney (BHK) and production of Antithrombin III (AT III) are presented.
Amino acids, L l-Lactate Immobilized enzyme Process monitoring

"Continuous Spectrophotometric Determination Of Copper, Nickel, And Zinc In Copper-base Alloys By Flow Injection Analysis"
Talanta 1981 Volume 28, Issue 6 Pages 389-393
Rokuro-Kuroda* and Tadashi Mochizuki

Abstract: Flow-injection methods have been developed for the determination of copper, nickel and zinc in copper-base alloys, including several types of brasses, deoxidized copper, beryllium copper and German silver. The system for copper and nickel involves the measurement of the absorbance of the copper(II) and nickel(II) aquo-complexes at 805 and 410 nm, respectively, after simple dissolution of the sample in a nitric acid-phosphoric acid mixture. The system needs no further reagents and the sample solutions can be analyzed at rates of up to 280 /hr for copper (or nickel in German silver) without any carry-over. The system for zinc consists of automatic dilution of the injected sample with a thiosulphate-acetate buffer solution and the subsequent measurement of the absorbance of the zinc-Xylenol Orange complex at 568 nm. This system permits analysis rates of up to 90/hr for zinc solutions, with no carry-over. The procedures have been applied to standard copper-base alloys. The results agreed satisfactorily with the certified values. The precision ranges are 0.2-0.7% for copper and nickel and 0.5-0.8% for zinc.
Copper Nickel Zinc Spectrophotometry

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

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

"Determination Of Water In Ethanol And Acetone By Direct Injection Enthalpimetry Based On The Heat Of Dilution"
Talanta 1984 Volume 31, Issue 1 Pages 82-84
Walace A. De Oliveira and Celio Pasquini

Abstract: Two analytical procedures based on the magnitude of the heat of dilution and direct injection enthalpimetry have been developed for determination of water in ethanol and acetone. The results obtained by means of the heat of dilution were compared with the values given by pycnometry, and gave a relative difference in the range 0.2-3%. The precision depends on the slope of the calibration curve, which varies with the procedure and the concentration of the sample.
Water Enthalpimetry

"Determination Of Pentachlorophenol By Flow Injection Analysis With Spectrophotometric Detection"
Talanta 1988 Volume 35, Issue 8 Pages 601-604
M. Rodriguez-Alcala, P. Ya&ntilde;ez-Sede&ntilde;o and L. Ma. Polo Diez

Abstract: Flow injection analysis was carried out by conventional and stopped-flow methods. The sample solution (120 µL) was injected into the 20 mM 4-aminoantipyrine carrier solution (1.2 mL min-1); the oxidant solution was 10 mM Fe(CN)63- (1.5 mL min-1), and absorbance was measured at 637 nm. The reactor tube was 90 cm x 0.7 mm for the conventional system and 30 cm x 0.5 mm for the stopped-flow system, the latter having a 10-s delay time and 20-s stop time. Calibration graphs for both systems were rectilinear from 1.0 to 60.0 µg mL-1 of pentachlorophenol. The greater selectivity of the stopped-flow system allowed analysis of commercial formulations which contained 15% of other chlorophenols.
Pentachlorophenol Spectrophotometry Stopped-flow

"Potentiometric And Spectrophotometric Determination Of Calcium In The Wet End Of Paper Machines By Flow Injection Analysis"
Talanta 1993 Volume 40, Issue 1 Pages 95-99
Johan Nyman and Ari Ivaska*

Abstract: Paper machine back water was acidified to pH 4 with HCl (before or after filtering), injected into a stream of water at 0.5 mL min-1 and merged with 0.02 M quinolin-8-ol (0.9 mL min-1) buffered with 2-amino-2-methylpropan-1-ol to pH 10.5, which acted as a masking agent for Mg2+. After passing through a reaction coil (30 cm x 0.5 mm) the stream was treated with 0.15 mM o-cresolphthalein complexon solution (2.4 mL min-1) in a second coil and the absorbance of the solution was measured at 570 nm. The calibration graph was rectilinear in the range 10 to 250 ppm of Ca2+. For the potentiometric determination, the sample (20 µL) was injected into water as above and merged with a stream of 0.28 M NaNO3 at 0.5 mL min-1. After passage through a reaction coil (90 cm x 0.5 mm) the Ca2+ in the solution was measured with a flow-through ion-selective electrode vs. Ag - AgCl. The response was rectilinear in the range 10 to 300 ppm. The spectrophotometric method gave Ca values slightly higher than those of the potentiometric method.
Calcium Potentiometry Spectrophotometry 8-Hydroxyquinoline

"Simultaneous Multi-element Analysis Of Blood Serum By Flow Injection Inductively Coupled Plasma Atomic Emission Spectrometry"
Analyst 1984 Volume 109, Issue 3 Pages 327-332
Cameron W. McLeod, Paul J. Worsfold and Allan G. Cox

Abstract: For the determination of Na, K, Ca, Mg, Li, Cu, Fe and Zn, the sample (2 µL to 2 ml) of serum or standard aqueous solution was injected into a carrier (aqueous solution of non-ionic surfactant at 2.2 mL min-1) for nebulization and ICP-AES The plasma emission was examined in a 30-channel direct-reading spectrometer interfaced to a microcomputer for data acquisition and analysis (peak areas were measured). Detection limits depended on the volume injected; the method was sufficiently sensitive to determine all the elements except Li in 20 µL of human serum. Matrix effects occurred with undiluted serum, but were decreased by use of relatively high r.f. power and low injection volume; dilution (1:1) of the serum eliminated the interference.
Calcium Copper Iron Lithium Magnesium Potassium Sodium Zinc Spectrophotometry Interferences Multielement

"Determination Of Water By Flow Injection Analysis Using Karl Fischer Reagent With Electrochemical Detection"
Analyst 1985 Volume 110, Issue 7 Pages 847-849
Richard E. A. Escott and Arthur F. Taylor

Abstract: The flow injection determination of water in organic samples by use of amperometric and potentiometric detection systems with different electrode combinations and cell configurations was studied; the best results were obtained in a potentiometric system with a platinum indicator electrode and a calomel or silver reference electrode. In the procedure described, samples (50 µL) were injected via an autosampler into a stream (0.56 mL min-1) containing a 20% solution of Karl Fischer reagent in methanol - xylene (1:1), which was then passed through an 80-cm mixing coil. The detector comprised a 1.5-mm diameter horizontal tube with the indicator electrode sealed into the base upstream of a ceramic plug, which was also sealed into the base and connected by silicone-rubber tubing to the reference electrode, which was elevated above the tube. Calibration graphs based on peak height were rectilinear for 0 to 1500 ppm of water and the max. sampling rate was 60 h-1. The method was also applied to the analysis of gasoline - alcohol blends.
Water Amperometry Electrode Karl Fischer analysis Potentiometry

"Chemically Immobilized Enzyme Electrodes For Hydrogen Peroxide Determination"
Analyst 1988 Volume 113, Issue 12 Pages 1811-1815
M. Cosgrove, G. J. Moody and J. D. R. Thomas

Abstract: The electrodes were prepared by immobilizing peroxidase(I) or catalase(II) on activated nylon by the method of Mascini et al. (Anal. Chim. Acta, 1983, 146, 135). The modified net was placed over a Pt electrode for I and O electrode for II. The I-immobilized electrode was applied in a flow injection system for determination of H2O2 in which sample solution (pH 7) was injected into a carrier stream (2.0 mL min-1) of 0.1 M phosphate buffer (pH 7) and 10 mM K4Fe(CN)6 and determined at -0.1 V vs. a Ag - AgCl reference electrode. The calibration graph was rectilinear from 5.25 µM to 1.75 mM H2O2. For 17.5 and 175 µM-H2O2, the coefficient of variation were 1% (n = 10). Several compounds at concentration. of 0.1%, e.g., ethanol, acetic acid and phenol did not interfere, but formaldehyde and ascorbic acid did. The II-immobilized electrode was applied in the dip-type mode to determine H2O2 in 0.1 M Tris buffer (pH 10). The calibration graph was rectilinear from 6.96 µM to 2.63 mM H2O2, and at 700 µM the coefficient of variation was 3% (n = 12). The storage and lifetime of the electrodes are discussed, and industrial and environmental applications are proposed.
Hydrogen peroxide Amperometry Electrode Apparatus Detector Interferences Immobilized enzyme

"Determination Of Hexavalent Chromium In Industrial Hygiene Samples Using Ultrasonic Extraction And Flow Injection Analysis"
Analyst 1997 Volume 122, Issue 11 Pages 1307-1312
Jin Wang, Kevin Ashley, Eugene R. Kennedy and Charles Neumeister

Abstract: A simple, fast, and sensitive method was developed for the determination of hexavalent chromium (Cr(VI)) in workplace samples. Ultrasonic extraction in alkaline solutions with 0.05 M (NH4)2SO4-0.05 M NH3 provided good extraction efficiency of Cr(VI) from the sample and allowed the retention of Cr(VI) on an ion-exchange resin (95%). The Cr(VI) in the sample solution was then separated as an anion from trivalent chromium [Cr(III)] and other cations by elution from the anion-exchange resin with 0.5 M (NH4)2SO4 in 0.1 M NH3 (pH 8) buffer solution. The eluate was then acidified with hydrochloric acid and complexed with 1,5-diphenylcarbazide reagent prior to flow injection analysis. By analyzing samples with and without oxidation of Cr(III) to Cr(VI) using Ce(IV), the method can measure Cr(VI) and total Cr. For optimizing the separation and determination procedure, preliminary trials conducted with two certified reference materials (CRMs 013-050 and NIST 1633a) and three spiked samples (ammonia buffer solution, cellulose ester filters and acid washed sand) indicated that the recovery of Cr(VI) was quantitative (> 90%) with this method. The limit of detection for FIA-UV/VIS determination of the Cr-diphenylcarbazone complex was in the sub-nanogram range (0.11 ng). The technique was also applied successfully to a workplace coal fly ash sample that was collected from a power plant and paint chips that were collected from a heating gas pipe and a university building. The principal advantages of this method are its simplicity, sensitivity, speed and potential portability for field analysis.
Chromium(VI) Chromium(III) Sample preparation Spectrophotometry Reference material Speciation

"Electrothermal Atomic Absorption Spectrometry In Occupational And Environmental Health Practice - A Decade Of Progress And Establishment. A Review"
J. Anal. At. Spectrom. 1994 Volume 9, Issue 3 Pages 405-414
Dimiter L. Tsalev

Abstract: A review is presented of developments in the determination of 52 elements by the cited technique. Instrumentation, chemical modifiers, reaction media, sample decomposition, atomizer design, fast temperature programmes, in-situ ashing, flow injection pre-concentration and element speciation are critically discussed with respect to occupational and environmental health applications. (170 references).
Trace elements Spectrophotometry Review Preconcentration Speciation

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

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

"Slurry Injection Atomic Absorption Spectrometry For Analysis Of Whole Coal"
Anal. Chem. 1979 Volume 51, Issue 12 Pages 1905-1915
James E. O'Reilly and Donald G. Hicks

Abstract: A method is described which permits the determination of a wide variety of major-, minor-, and trace-level elements directly in powdered whole coal by aspiration of aqueous slurries into a conventional atomic absorption spectrophotometer. Relative precisions and accuracies are in the range of ±1-5% and 5-25%, respectively. The relative atomization efficiencies of almost every element studied are remarkably constant; an element in a coal matrix will produce an absorption signal 20±6% that of a purely aqueous solution of equivalent concentration. The details of sample preparation, the most critical aspect of the entire procedure, and which must be carefully and reproducibly performed, are given. Considerable savings in operator and turnaround times over normal ashing-acid dissolution procedures can be achieved.
Copper Chromium Iron Nickel Strontium Zinc Spectrophotometry Slurry

"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 Spectrophotometry Optimization Simplex Standard additions calibration Reverse Viscosity

"Spectrophotometric Determination Of Water By Flow Injection Analysis Using Conventional And Pyridine-free Two-component Karl-Fischer Reagents"
Anal. Chem. 1985 Volume 57, Issue 13 Pages 2571-2575
Ingrid Nordin-Andersson and Anders Cedergren

Abstract: The cited flow injection method was evaluated by using a large number of organic solvents with refractive indices ranging from 1.32 to 1.50 at 20°C. The conventional Karl Fischer reagent and three commercial two-component pyridine-free reagents (Merck, ReAquant and Hydranal) were used. The mean deviation between flow injection and coulometric values was 0.0014% (v/v) of water. Triethylamine gave rise to increased interference effects, while less influence from ketal-forming samples was found for the two-component reagents. The latter effect was not noticed for Hydranal.
Water Karl Fischer analysis Spectrophotometry Interferences Method comparison

"Methods For The Determination Of Inorganic Anions. 1. Spectrophotometric Trace Determination Of Chloride In Air, Water And Technical Products In The Iron(II) - Mercury - TPTZ System. Manual, CF And Flow Injection Analysis Methods"
Fresenius J. Anal. Chem. 1983 Volume 315, Issue 3 Pages 197-200
Bernd R&ouml;ssner und Georg Schwedt

Abstract: The application of the Fe(II)/Hg-tripyridyl-s-triazine system for the photometric trace analysis of chloride in the range of 10 g/l to 10 mg/l is shown. The improvement of the method for optimum results leads in the continuous-flow-technique to a detection limit of 5 g/l. A manual procedure for the range of 1-10 mg/l is also described. As examples for application, determinations of chloride in natural waters, p. a. salts, in a bitumen sample and in air are described.
Chloride Spectrophotometry Method comparison

"Expansion Of The Dynamic Range Of Flow Injection Analysis Systems For Complete Batch Process Monitoring"
Fresenius J. Anal. Chem. 1988 Volume 329, Issue 6 Pages 678-684
C. Thommen, M. Garn und M. Gisin

Abstract: Online monitoring of industrial processes requires a wide dynamic range, and methods to achieve this are discussed. Of two methods described in detail, the simpler involves combination of peak height measurement with electronic dilution or peak-width measurement, the latter being used when the concentration. is too high for peak height to be used. An example given is the determination of aromatic amines. For more precise measurements, gradient dilution can be used with time-variable zone sampling, as in the monitoring of glucose in fermentation processes.
Amines, aromatic Calibration Dilution Gradient technique Merging zones Peak width Process control Review Theory Zone sampling Process monitoring

"Flow Injection Analysis - A Survey Of Its Potential As Solution Handling And Data Gathering Technique In Chemical Research And Industry"
Fresenius J. Anal. Chem. 1988 Volume 329, Issue 6 Pages 653-655
Jaromir Ruzicka

Abstract: The possible applications of flow injection analysis are reviewed briefly, with examples described diagrammatically. Uses considered are, as a tool for serial assay, continuous monitoring and process control, miniaturization and integration, as a link between chemical and instrumental methods, to enhance detector performance and as an impulse response technique. (12 references).
Miniaturization Impulse response Process control Review

"Automated Dilution In Flow Injection Analysis With Double Online Dialysis. System For The Determination Of Chloride In Industrial Effluents And Plating-bath Solutions"
Fresenius J. Anal. Chem. 1991 Volume 340, Issue 7 Pages 415-418
J. F. van Staden

Abstract: A flow diagram is shown for the determination of Cl- by injection of the sample into water (carrier stream), followed by online dialysis across Technicon type C membranes in two separate stages against water, and reaction with Hg(SCN)2 - Fe(NO3)3 color reagent (prep. described) before spectrophotometry at 480 nm. No samples prep. or dilution is necessary; 100 samples can be analyzed in 1 h. The coefficient of variation (n = 15) for 8 to 60 g L-1 of Cl- was 0.8%. Results agreed with those obtained by a standard automated segmented method involving manual dilution.
Chloride Spectrophotometry Automation Dialysis Dilution Membrane

"Online Dilution With Sequential Injection Analysis: A System For Monitoring Sulfate In Industrial Effluents"
Fresenius J. Anal. Chem. 1997 Volume 357, Issue 6 Pages 577-581
J. F. van Staden and R. E. Taljaard

Abstract: Two manifold sequential injection analysis systems were evaluated: one included a dilution step (system A) and one had a dilution coil in the manifold (system B). The components of each system are illustrated. Flow rates for both systems were 5 ml/min. Standard sulfate solutions were prepared from 1-5000 g/l. Barium chloride reagent solution was used, containing potassium hydrogen phthalate/HCl buffer of pH 2.5, filtered to 45 µm. The device sequences of the two systems are tabulated. For system A, dilution is carried out in the well defined water zone between the barium chloride reagent and the sample zone with a timing sequence from 0-15 S. In addition, 47g EDTA/ammonium chloride (40:7) and 57 mL ammonia were dissolved in 600 mL water, diluted to 1l and this buffer was introduced between samples at the start of each sequence. Calibration graphs were linear from 50-5000 mg/l sulfate for system B; RSD were n=10) for both systems. The merits of each system are discussed.
Sulfate Turbidimetry Dilution Sequential injection

"Determination Of Calcium In Chlor-alkali Brine By Flow Injection Analysis"
Microchim. Acta 1985 Volume 87, Issue 5-6 Pages 393-400
H. Wada, Y. Deguchi and G. Nakagawa

Abstract: For calcium concentration of 1 mg L-1 in brine, the sample is diluted five times and injected into the flow injection system. For lower concentration, pre-concentration is achieved by passing the saturated brine, adjusted to pH 10 to 10.5 and at 60°C, through an acid- and alkali-washed column of Duolite ES-467 resin, from which Ca is eluted with 0.5 M HCl, the neutralized and diluted solution being injected for analysis. Samples enter a buffer stream (0.02 M Na2B4O7 of pH 8.0 containing 0.08 M NaCl) and react with a chromogenic solution containing 80 µM-ZnEGTA, 30 µM-3-{N-[4-(3,5-dibromo-2-pyridylazo)-3-hydroxyphenyl]-N-ethylamino}propanesulfonic acid and 0.02 M Na2B4O7 (pH 8.0). The absorbance of the resulting solution is measured at 564 nm. The calibration graph is rectilinear for 0.25 to 1.75 mg L-1 of calcium. Sample throughput is 40 h-1. Tervalent Fe, Cu(II) and Ni(II) can be masked with N-(dithiocarboxy)sarcosine, but Cd, Mn(II) and Zn interfere. The method has been applied to the determination of 20 to 80 µg L-1 of Ca in brine for the chlor-alkali process.
Calcium Spectrophotometry Interferences Resin Preconcentration

"Measurement Of Protein Using Flow Injection Analysis With Bicinchoninic Acid"
Anal. Biochem. 1987 Volume 161, Issue 1 Pages 152-156
Lawrence C. Davis* and Gary A. Radke

Abstract: The bicinchoninic acid reagent developed by Pierce Chemical Co. was used in the determination of proteins in a flow injection analyzer comprising ~8 ft of PTFE tubing (0.5 mm i.d.) with a peristaltic pump, a controlled-temperature water bath (reaction temperature was 72°C), and a spectrophotometer with flow cell. The sensitivity was comparable with that of the Lowry method. Results were obtained in <1 min at a rate of up to 60 h-1. Sample size was 5 to 20 µL and the response was rectilinear up to 10 µg of protein. We have used the bicinchoninic acid reagent developed by Pierce Chemical Co. to measure proteins in a simple flow injection analyzer. The sensitivity is comparable to that of the Lowry method and no pipetting of reagents is needed. Results are obtained in less than 1 min and samples may be run at a rate of 60/h. The response is linear over a range of protein concentration (0-10 µg) and sample size (5-20 µL) convenient for most analytical requirements. A peristaltic pump, a controlled-temperature water bath, and a spectrophotometer with flow cuvette are the only special apparatus required.
Proteins Spectrophotometry Heated reaction Method comparison

"The Analysis Of Galvanizing Preflux Solutions For Zinc By Flow Injection Flame Atomic Absorption Spectrometry"
Anal. Lett. 1986 Volume 19, Issue 15&16 Pages 1573-1590
Davey, D.E.

Abstract: Flow manifolds producing flow rates of 4.2 to 6 mL min-1 are described. Zinc in galvanizing solution (10 to 180 µL) and in Zn standards (containing 0 to 25 mg l-1) is determined by flow injection - flame AAS with a Techtron AA3, a Varian-Techtron 1100, or a GBC 901 spectrometer at 213.9 nm (in the mg L-1 range) and 307.6 nm (in the g L-1 range). Recoveries were 93.2 to 105.9%. Zinc can be determined in galvanizing preflux solution at up to 110 g L-1 with coefficient of variation of 6.6%; high levels of KCl, NaCl and NH4Cl do not significantly interfere.
Zinc Spectrophotometry Interferences

"Column Liquid Chromatography In Combination With Immobilized Enzymes And Electrochemical Detection And Its Applications In Some Industrial Processes"
Electroanalysis 1992 Volume 4, Issue 4 Pages 403-427
Gy&ouml;rgy A. Marko-Varga

Abstract: A review, with 206 references. The first part of the paper provides a review of the pre- and post-column derivatization systems used in column liquid chromatography (CLC) in combination with immobilized enzyme reactors (IMERs) and electrochemical detection (EC). In the second part, an outline of important factors to consider in the optimization of CLC-IMER-EC systems are presented. Three industrial applications are described utilizing enzyme-based detection or enzymes for sample handling purposes. In two of the cases, CLC-IMER were used in combination with amperometric detection using chemical modified electrodes (CME). These applications were performed in the author's lab., and the high selectivity and sensitivity of these systems as well as the problems encountered in these complex samples will be discussed.
HPLC Electrochemical analysis Review Post-column derivatization Pre-column derivatization Immobilized enzyme Optimization

"Determination Of Dissolved Hexavalent Chromium In Industrial Waste Water Effluents By Ion Chromatography And Post-column Derivatization With Diphenylcarbazide"
J. Chromatogr. A 1991 Volume 546, Issue 1 Pages 335-340
Elizabeth J. Arar and John D. Pfaff

Abstract: A previously described method ('Dionex Technical Note', No 26, Dionex Corp., Sunnyvale, CA, 1990) for the ion-chromatographic determination of Cr(VI) as its complex with diphenylcarbazide was applied to industrial effluents. All samples were stored on ice and analyzed within 4 h of collection and again the next day. Aqueous samples were filtered and adjusted to pH 9 to 9.5 (optimum) before analysis. The method was not applicable to solid wastes. For waste water, recoveries were quantitative and no oxidation of Cr(III) and Cr(VI) occurred.
Chromium(VI) HPIC Filter pH Post-column derivatization

"Flow Injection Sorbent Extraction With Dialkyl Dithiophosphates As Chelating Agent For The Determination Of Cadmium, Copper And Lead By Flame Atomic Absorption Spectrometry"
Spectrochim. Acta B 1996 Volume 51, Issue 14 Pages 1917-1923
Renli Ma and Freddy Adams*

Abstract: Of the OO-dialkyl phosphorodithioates evaluated for retention of the cited heavy metals on a Perkin-Elmer B050-4047 C18 column containing 20 mg of ODS silica gel (cf. Anal. Chim. Acta, 1994, 285, 33), the best was diethyl phosphorodithioate in the presence of 0.1 M citrate at pH 3 (buffered with ammonium acetate). With loading for 20 s at 8.7 ml/min the enhancement factors for the cited metals were 35, 35 and 26 and the detection limits were 0.8, 1.4 and 10 µg/l, respectively. The method is applicable to digests of environmental, biological and industrial materials.
Cadmium Copper Lead Sample preparation Spectrophotometry Sample preparation Chelation Solid phase extraction C18 Silica gel

"Cold Vapor Atomic Absorption Determination Of Mercury By Flow Injection Analysis Using A Teflon-membrane Phase Separator Coupled To The Absorption Cell"
Spectrochim. Acta B 1983 Volume 38, Issue 10 Pages 1329-1338
J. C. de Andrade, C. Pasquini and N. Baccan, J. C. Van Loon

Abstract: The flow cell described acts as a gas-liquid phase separator based on the permeability of PTFE to elementary Hg. It comprises two pieces of machined acrylic plastic placed in the optical path of an AAS instrument, with a piece of PTFE tape (0.23 mm thick) sandwiched between them, separating the cell and the optical path. The reaction mixture of an acid (0.25 M HCl) test solution and 0.5% NaBH4 solution in 0.05 M KOH passes through an exchange area in the upper part of the cell, from which elementary Hg is transported across the membrane into the optical path of a 15 cm open flow cell in the lower part of the apparatus. Absorption is measured at 253.7 nm, and the calibration graph is rectilinear for 70 ng mL-1. The detection limit is 1.4 ng mL-1 of Hg in the initial solution Samples can be processed at 110 per hour. Optimum operating parameters and the effects of interfering species on the system are reported. A flow injection analysis (FIA) procedure for the determination of trace amounts of Hg by the cold vapor atomic absorption (CVAAS) method was presented. In order to make efficient use of the FIA technique, a new flow cell was developed to permit a rapid separation of elemental Hg from the carrier solution. The design of this device was based on the permeability of Hg(0) in commercially available Teflon (PTFE) tape, which acted as a membrane phase separator. The calibration curve was linear up to 70 ng/ml (0.005 + 0.008 Hg ng/mL; r = 0.9996) using a 15 cm open cell approach, with a detection limit of 1.4 ng/ml (0.66 ng Hg), considering a signal to noise ratio of 3. SD was ±0.004 absorbance, calculated at a level of 50 ng/mL Hg(II). The sampling rate was 110 samples/h.
Mercury Spectrophotometry Interferences Phase separator Teflon membrane Flowcell Signal to noise ratio

"Industrial Applications Of Flow Injection Analysis"
Am. Lab. 1986 Volume 18, Issue 3 Pages 154-157
Whitaker, M.J.

Abstract: Some of the advantages and uses of flow-injection analysis in industry are reviewed with three references. (SFS)
Process control Review

"Fundamental Study Of The Determination Of Iron And Cobalt Using 5-dimethylamino-2-nitrosophenol As Color Reagent By Continuous-flow Stream Propelled By Gas Pressure"
Bunseki Kagaku 1983 Volume 32, Issue 3 Pages 191-196

Abstract: The flow streams are propelled by gas pressure in the flow injection system, and 2-nitroso-5-dimethylaminophenol (nitroso-DMAP) is used as the color reagent for iron and cobalt. The signals were detected with a spectrophotometer equipped with a flow cell (18 µL). For the determination of iron(II), the reagent and carrier stream solutions were the nitroso-DMAP solution (pH 9.2) and 10^-3 M sulfuric acid solution respectively, and were flowed at about 1 mL/min, and the signals were detected at 750 nm. The calibration curve was linear from 2 x 10^-7 M to 5 x 10^-4 M of iron. For the detection of cobalt, the reagent stream and carrier stream solutions were the solution of nitroso-DMAP dissolved in trisodium citrate solution and 10^-3 M sulfuric acid solution, respectively. After mixing the reagent stream and carrier stream solutions in the reaction coil, the sulfuric acid solution (4M) was mixed in order to decrease the reagent blank and decompose other metal chelates such as iron, copper and nickel chelates, and the signals were detected at 530 nm. The calibration curve was linear from 5 x 10^-7 M to 6 x 10^-6 M of cobalt. By the proposed FIA system for cobalt, nickel at concentrations of 10^-3 M, iron(III) at concentrations of 10^-4 M, and iron(II) and copper at concentrations of 5 x 10^-5 M did not interfere with the determination of cobalt, and 0.001% to 0.06% of cobalt in commercially available nickel salts were determined.
Iron Cobalt Spectrophotometry Interferences

"Flow Injection Analysis Moves Into CPI Plants"
Chem. Eng. 1986 Volume 93, Issue 1 Pages 14-15
Mascone, C.F.

Abstract: NA
Process control Review

"Flow Injection Analysis. A New Technique In Analytical Chemistry"
FMBRA Bull. 1985 Volume 5, Issue NA Pages 210-NA
Osborne, B.G.;Barrett, G.M.

Abstract: NA
Bromate Iron Spectrophotometry Tecator

"Thin Transducer As Detector For Trace Organics"
Ind. Res. Dev. 1981 Volume 23, Issue 5 Pages 148-153
houp, Ronald E.; Bruntlett, Craig S.; Kissinger, Peter T.; Jacobs, Wesley A. (SFS)

Abstract: A review with 14 references. The use of thin-layer electrochemical transducer, especially amperometric transducer, for chromatography and flow-injection anal. for trace organics in environmental, industrial, and biochemical study is discussed. (SFS)
Trace organics HPLC Apparatus Detector

"Electrochemical Analysis Of Sulfur Compounds Of Environmental Interest"
Int. J. Environ. Anal. Chem. 1985 Volume 20, Issue 3-4 Pages 167-177
Thomas, J.D.R.

Abstract: A review is presented, largely of work carried out at UWIST, with emphasis on the use of S2--selective electrodes for monitoring industrial liquors (e.g., black liquor) and effluents and sewage effluents and for monitoring the growth of S2--producing bacteria, of importance in the context of industrial spoilage, and also on flow injection analysis with use of ion-selective electrodes and on means of overcoming interference by H2O2. (30 references).
Sulfide Electrode Interferences Review

"Flow Injection Analysis: Potential For Process Composition Measurement"
InTech 1984 Volume 31, Issue 5 Pages 51-54
Mowery, R.A.

Abstract: A review is presented, with 16 references, in which sample dispersion and concentration. profiles are discussed and applications to redox and acid - base measurements are described.
Acids Bases Hydrogen peroxide Dispersion Review Redox Process control

"Solid-phase Spectrophotometry"
J. Anal. Chem. 1995 Volume 50, Issue 4 Pages 440-446
Brykina, G.D.;Marchenko, D.Y.;Shpigun, O.A.

Abstract: A review is presented of the trends in development of solid-phase spectrophotometry over the last 6 years. The measurement technique and the sample preparation were considered the most important factors for precise results. (54 references).
Metals, rare earth HPLC Ion exchange Review Solid phase detection

"Adaptation Of A Cold Vapor Mercury Analyzer To Flow Injection Analysis"
J. Autom. Methods Manag. Chem. 1988 Volume 10, Issue 4 Pages 188-191

Abstract: A Coleman MAS-50A Mercury Analyser system was modified to allow the determination of Hg by flow injection analysis. Samples were digested either by the conventional EPA method or by a simplified procedure involving addition of concentrated HNO3 - H2SO4 (1:1), cooling to room temperature and addition of 6% KMnO4 solution before analysis within 15 min. A sample was mixed with carrier solution (1% HNO3 solution) and then with a 35% (w/v) solution (10% solution for EPA digestion procedure) of SnCl2 in 1% HNO3, before stripping of Hg from the aqueous solution with N (200 mL min-1). The mixture then passed to a gas - liquid separation cell (illustrated) and thence to the detector. The calibration graph was rectilinear for up to 25 µg of Hg. Average recovery of Hg was 96%. Results agreed with those obtained by the EPA procedure.
Mercury Spectrophotometry Sample preparation Method comparison Optimization Phase separator

"Stabilized Filter-supported Bilayer Lipid Membranes (BLMs) For Automated Flow Monitoring Of Compounds Of Clinical, Pharmaceutical, Environmental And Industrial Interest"
J. Autom. Methods Manag. Chem. 1997 Volume 19, Issue 1 Pages 1-8

Abstract: The method and apparatus for the preparation of phosphatidylcholine/dipalmitoylphosphatidic acid membranes, containing enzymes or antibodies, cast on glass microfiber or polycarbonate ultrafiltration membranes are described [cf. Anal. Chem., 1995, 67, 936; Electroanalysis (N.Y.), 1995, 7, 531, 1082]. The membranes were used in flow injection amperometric determinations of (i) substrates (e.g., acetylcholine, penicillin and urea) of hydrolytic enzymes, and (ii) antigens (e.g., thyroxine and triazine herbicides).
Acetylcholine Penicillin Urea Thyroxine Triazines Clinical analysis Biochemical analysis Amperometry Supported lipid membrane Polycarbonate membrane Glass microfiber

"Determination Of The Phosphorus Content In The Wet Process For Phosphoric Acid Production By Flow Injection Analysis"
Huazhong Shifan Daxue Xuebao (Ziran Kexue Ban) 1988 Volume 22, Issue 2 Pages 182-186
Chen, Yeqing; Zhao, Tingren; Du, Yunqing (SFS)

Abstract: A method of FIA (Flow Injection Analysis) employed to measure the phosphorus content in the technological process of numid-phosphorue acid has been described in this paper. This mixture of ammonium molybdate and ammonium vanadate is served as a developer and a solution 0.48 mol L-1 hydrochloric acid as the carrier steam, in the method, which has been applied to the acid-solution and the extracted residual solution. The content of phosphorus ranging from 0 to 500rag/1 is able to be determined with satisfied results, which can be printed out directly by a computer. The datas obtained from the method are in agreement with those from the neutral titration.
Phosphorus Spectrophotometry

"Flow Injection Analysis Determination Of Phosphoric Acid In Phosphorization Solution"
Lihua Jianyan, Huaxue Fence 1988 Volume 24, Issue 5 Pages 305-319
Wang, S.;Mei, K.;Luo, Y.

Abstract: Phosphate solution (~1 mg mL-1; 100 µL) is fed into a flow injection analysis apparatus (Liaoning Precision Instruments) and allowed to react with 6% (NH4)6Mo7O24 - 0.6% NH4VO3 solution in 26% HNO3 to give a brilliant yellow complex, which is determined spectrophotometrically at 460 nm (details given). The coefficient of variation is 0.7% (n = 9). Results are satisfactory and compare well with those obtained by an ion exchange - neutralization method. The method is simple, and 120 samples can be analyzed in 1 h.
Phosphoric acid Spectrophotometry Method comparison

"Flow Injection Analysis: Beyond The Laboratory Curiosity Stage"
Trends Anal. Chem. 1987 Volume 6, Issue 7 Pages 165-168
G. E. Pacey, B. P. Bubnis

Abstract: The advantages of flow injection analysis, industrial applications and future developments are discussed.
Review Tecator

"Determination Of Water In Organic Solvents By Using The Karl Fischer Method With Flow Injection Analysis"
Z. Chem. 1984 Volume 24, Issue 2 Pages 75-76
Helmut M&uuml;ller, G&uuml;nter Wallaschek

Abstract: Liquid paraffin is pumped into the reservoir to force the Karl Fischer reagent in two parallel streams into phase-separation vessels; in this way the reagent does not make contact with the pump tubing. The lower (reagent) phase from the separation vessels flows to the detection system; one stream passes the sample-introduction system and traverses a delay coil. A µflow-through I--selective electrode (Ag2S type) is used for potentiometric measurement, and the differential response is recorded. Calibration standards are included in each series of analyzes to compensate for changes in electrode response as its surface acquires an iodine-containing coating. From 0.01 to 5% (w/w) of water can be determined with a coefficient of variation of 3%, and 50 to 60 samples (e.g., 30 µL) can be analyzed in 1 h; only 0.9 mL of reagent is needed per determination.
Water Electrode Karl Fischer analysis Potentiometry

"Continuous-flow Analysis. Determination Of Iron In Technological Solutions"
J. Anal. Chem. 1992 Volume 47, Issue 7 Pages 1211-1217
Rodionova, T.V.;Beklemishev, M.K.;Dracheva, L.V.;Zolotov, Y.A.

Abstract: A flow diagram is given of an automated continuous-flow analysis (CFA) system for the spectrophotometric determination of Fe(II) and Fe(III) with sulfosalicylic acid or 1,10-phenanthroline at 505 nm or with SCN- at 480 nm; samples can be injected at rates of 180, 100 and 140 h-1, respectively. The determination of Fe by CFA with SCN- is more sensitive than by flow injection analysis. The method was used to determine 0.05 to 0.1 µg mL-1 of Fe in technological solution with coefficient of variation of 3 to 12%.
Iron(2+) Iron(III) Spectrophotometry Speciation