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: Alloy -> steel

Citations 88

"On-line Electrolytic Dissolution Of Alloys In Flow Injection Analysis - Determination Of Iron, Tungsten, Molybdenum, Vanadium And Chromium In Tool Steels By Inductively Coupled Plasma Atomic Emission Spectrometry"
Anal. Chim. Acta 2000 Volume 405, Issue 1-2 Pages 213-219
Ana Paula G. Gervasio, Gilmara C. Luca, Amauri A. Menegário, Boaventura F. Reis and Henrique Bergamin Filho

Abstract: A flow injection procedure involving on-line anodic electrolytic dissolution for Fe, W, Mo, V and Cr determination in tool steels by inductively coupled plasma atomic emission spectrometry is proposed. The sample is dissolved in an electrolytic cell coupled to the spectrometer nebulizer and a 1.5 mol L-1 HNO3 electrolytic solution is used to close the electric contact between electrodes. The system permits direct analysis of 30 solid samples per hour (150 determinations) and yields results with a relative standard deviation (r.s.d) lower than 5 % (n = 5). The applicability of the procedure was verified by analyzing tool steels samples and accuracy was assessed by comparison with a conventional sample dissolution procedure.
Iron Tungsten Molybdenum Vanadium Chromium Spectrophotometry Electrochemical dissolution

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

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

"Flow Injection Calibration Methods For Atomic Absorption Spectrometry"
Anal. Chim. Acta 1983 Volume 145, Issue 1 Pages 159-168
J. F. Tyson, J. M. H. Appleton and A. B. Idris

Abstract: The use of an atomic absorption spectrometer as a detector in flow injection analysis is briefly reviewed. A new simplified model is described for the dispersion effects observed with such systems; the model is based on considering the dispersion to be due to a single hypothetical mixing chamber located immediately prior to the measurement stage. The utility of this approach is demonstrated for two methods of calibration commonly used in atomic absorption spectrometry, and it is shown that flow injection sample and standard handling techniques are comparable to manipulation with volumetric apparatus. The flow injection method has a number of advantages for the analogue of the standard addition method. The use of an exponential concentration gradient is proposed as a novel method of calibration using a single concentrated standard. Results are presented for the determination of chromium in standard steels.
Chromium Spectrophotometry Calibration Gradient technique Review Theory

"Transient Oxidation Of Brucine In Solution As A Tool For The Determination Of Chromium(VI) And Brucine"
Anal. Chim. Acta 1983 Volume 146, Issue 1 Pages 181-190
Takeshi Yamane and Horacio A. Mottola

Abstract: The oxidation of the alkaloid brucine by chromium(VI) in sulfuric acid medium in the presence and absence of oxalic acid is described. Photometric monitoring of a red intermediate (λmax = 525 nm) permits determinations of both chromium (VI) and brucine at low concentrations (Cr(VI), 0-7.5 µg mL-1; brucine, 0-197 µg mL-1) in an unsegmented continuous-flow system by direct injection of the sample into the detection area. Detection limits are 0.1 µg mL-1 for chromium and 4 µg mL-1 for brucine. Other alkaloids structurally related to brucine (e.g., strychnine, yohimbine and corynanthine) do not give intermediates with the high molar absorptivity exhibited by brucine. Determination of chromium in water samples and standards is described.
Chromium(VI) Brucine Spectrophotometry

"Rapid Determination Of Lead, Bismuth, Antimony, And Silver In Steels By Flame Atomic Absorption Spectrometry Combined With Flow Injection Analysis"
Anal. Chim. Acta 1983 Volume 153, Issue 1 Pages 23-31
Nangen Zhou, Wolfgang Frech and Erik Lundberg

Abstract: The sample (1 g) is dissolved in concentrated HCl (7 ml) plus concentrated HNO3 (3.5 ml), the mixture is filtered through a glass-fiber filter (Whatman GF/A), and the residue is washed with 5% HCl, with which the filtrate is then diluted to 12.5 g. A 90 µL portion of the solution is injected into a carrier stream of water (5.6 mL min-1) and introduced into an air - acetylene flame (this technique combines the advantages of pulsed nebulization with those of continuous introduction of the solvent). Calibration graphs are rectilinear for up to 1 ppm of Ag and 10 ppm of Sb, Bi or Pb in the solution, although separate calibrations are necessary for Ag, Bi and Sb in low- and high-alloy steels. Results for a variety of standard steels were generally in good agreement with certified or published values. The limits of detection for Ag, Bi, Pb and Sb are 0.3, 2.5, 2.5 and 10 µg g-1, respectively. The rate of sampling is 120 h-1
Lead Bismuth Antimony Silver Spectrophotometry Pulse nebulization Reference material

"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 Spectrophotometry Interferences Merging zones Method comparison Reference material Standard additions calibration

"Simple Procedure For Hydrodynamic Injection In Flow Injection Analysis Applied To The Atomic Absorption Spectrometry Of Chromium In Steel"
Anal. Chim. Acta 1986 Volume 181, Issue 1 Pages 265-270
E. A. G. Zagatto, O. Bahia Fo, M. F. Gin&eacute; and H. Bergamin o

Abstract: The technique is based on use of an electrically operated commutator to keep constant the dead volume arising from hydrodynamic pressure gradients and diffusion and requires only a simple flow injection system with one peristaltic pump operating continuously. A flow diagram and description of the proposed commutator system are given. Differences between effective sample size and the dimensions of the injection duct are emphasized, particularly for small volumes. The coefficient of variation are usually <1% for injections of 1 to 10 µL. The injection technique was assessed in a spectrophotometric model system with bromocresol green and its accuracy was measured for the determination of Cr (2.8 to 31.1% w/w) in 10 standard steels. The results agreed well with those obtained by ICP-AES and conventional AAS. With a sample rate of 120 h-1, coefficient of variation (n = 3) ranged from 0.26 to 2.69%.
Chromium Spectrophotometry Spectrophotometry Hydrodynamic injection Method comparison Valve

"Online Electrolytic Dissolution Of Alloys In Flow Injection Analysis. 1. Principles And Application In The Determination Of Soluble Aluminum In Steels"
Anal. Chim. Acta 1986 Volume 190, Issue 1 Pages 177-184
H. Bergamin F&deg;, F. J. Krug and E. A. G. Zagatto, E. C. Arruda and C. A. Coutinho

Abstract: Polished steel samples were dissolved by electrolysis in a special cell (details given) and the solution was passed directly to a flow injection manifold as described by Krug et al. (Ibid., 1986, 179, 103). Dissolved Al was determined spectrophotometrically at 535 nm afte reduction with Eriochrome cyanine R (C. I. Mordant Blue 3) solution containing HCl, ascorbic acid and hexamine for pH adjustment. Beer's law was not obeyed and a second-derivative equation was used. The effects of electrolysis time, c.d. and electrolyte composition and flow rate were studied.
Aluminum, soluble Spectrophotometry Optimization

"Online Electrolytic Dissolution Of Alloys In Flow Injection Analysis. 2. Spectrophotometric Determination Of Molybdenum In Steels"
Anal. Chim. Acta 1988 Volume 214, Issue 1-2 Pages 397-400
H. Bergamin F&deg;, F. J. Krug, B. F. Reis, J. A. Nobrega, M. Mesquita and I. G. Souza

Abstract: A solid sample was placed on a simple electrolytic chamber and 200 mA DC was applied for 8 s; the dissolved material served as the injected sample zone. The carrier electrolyte solution was 1 M KCl - 0.1 M HCl, the reducing reagent solution was 5% SnCl2.2H2O in 5 M HCl and the reagent solution was aqueous 6% KSCN (flow rates 3.7, 1.0 and 1.0 mL min-1, respectively). The optimum length of the main reaction coil was 150 cm and an 8-cm sampling loop was used. The Mo was determined spectrophotometrically. No measurable baseline drift was observed during continuous operation for 4 h. The calibration graph was rectilinear for up to 600 mg L-1 of Mo; the coefficient of variation (n = 10) for a standard sample containing 2.21% of Mo was 2.3%. (For Part I see Anal. Abstr., 1987, 49, 8B210).
Molybdenum Spectrophotometry Calibration Electrochemical dissolution Merging zones Optimization

"Flow Injection Extraction-spectrophotometric Determination Of Permanganate With The Ethylenebis(triphenylphosphonium) Cation"
Anal. Chim. Acta 1989 Volume 217, Issue 1 Pages 183-186
D. Thorburn Burns, N. Chimpalee, M. Harriott and G. M. Mckillen

Abstract: Buffer solution (citric acid - KH2PO4 - H3BO3 - diethylbarbituric acid - H2O; pH 6) was mixed with aqueous 10% NH4F before injection of the sample (250 µL). The solution was then mixed with aqueous 0.25% ethylenebis(triphenylphosphonium) bromide in a mixing coil (20 cm x 0.5 mm) before extraction with CHCl3. The mixture then passed to a phase separator and the absorbance of the organic phase was measured at 545 nm. The calibration graph was rectilinear for up to 25 µg mL-1 of Mn(VII), the detection limit was 0.58 µg mL-1 and the coefficient of variation (n = 10) was 1%. The method was applied in the determination of Mn in standard steel samples and results agreed well with certified values.
Permanganate Spectrophotometry Sample preparation Buffer Reference material Phase separator Extraction

"Flow Injection Extraction-spectrophotometric Determination Of Dichromate With The Tetramethylenebis(triphenylphosphonium) Cation"
Anal. Chim. Acta 1989 Volume 225, Issue 1 Pages 241-246
D. Thorburn Burns, N. Chimpalee and M. Harriott

Abstract: Samples (0.25 ml) were injected into a stream (0.85 mL min-1) of water which was mixed with a stream (0.85 mL min-1) of 1 M H2SO4. This mixture was merged with a stream (0.85 mL min-1) of aqueous 0.5% tetramethylenebis(triphenylphosphonium) bromide in a PTFE reaction coil (20 cm x 0.8 mm), and the resulting ion pair was extracted into CHCl3 in a second PTFE coil (0.4 m x 0.8 mm). The mixture was passed through a phase separator, and the absorbance of the organic phase was measured at 365 nm. The calibration graph was rectilinear for 20 µg mL-1 of Cr2O72-, and the detection limit was 0.44 µg mL-1. The method was applied in the determination of Cr2O72- in steel.
Dichromate Spectrophotometry Sample preparation Calibration Phase separator Ion pair extraction

"Flow Injection Spectrophotometric Determination Of Cobalt By Extraction As Tetrathiocyanatocobaltate(II) With The Ethylenebis(triphenylphosphonium) Cation"
Anal. Chim. Acta 1989 Volume 225, Issue 1 Pages 123-128
D. Thorburn Burns, N. Chimpalee and Michael Harriott

Abstract: Samples (0.5 ml) were injected (20 h-1) into a carrier stream (0.75 mL min-1) of aqueous 10% NH4F, which was mixed with a stream (0.75 mL min-1) of aqueous 5% NH4SCN in a PTFE coil (20 cm x 0.8 mm). The mixture was merged with a stream (0.75 mL min-1) of aqueous 0.5% ethylenebis(triphenylphosphonium)bromide, and the ion pair formed was extracted into CHCl3 in a second PTFE coil (0.4 m x 0.8 mm). After passage through a phase separator, the absorbance of the organic phase was measured at 625 nm. The calibration graph was rectilinear for up to 20 µg mL-1 of Co; the detection limit was 0.23 µg mL-1. The method was applied in the determination of Co in steel.
Cobalt Spectrophotometry Sample preparation Ion pair extraction Organic phase detection Phase separator

"Online Electrolytic Dissolution Of Alloys In Flow Injection Analysis. 3. Multi-elemental Analysis Of Stainless Steels By Inductively Coupled Plasma Atomic Emission Spectrometry"
Anal. Chim. Acta 1991 Volume 245, Issue 2 Pages 211-216
I. G. Souza, H. Bergamin Fo, F. J. Krug, J. A. N&oacute;brega, P. V. Oliveira, B. F. Reis and M. F. Gin&eacute;

Abstract: The simultaneous determination of chromium, nickel, manganese, silicon and iron in stainless steels was achieved by inductively coupled plasma atomic emission spectrometry (ICP-AES) after on-line electrodissolution using an improved flow-through electrolytic cell. The solution containing the electrodissolved ions was impelled by an air carrier stream in a flow-injection manifold towards a mixing-dilution chamber. From this chamber, the diluted and homogenized solution was aspirated and nebulized into the ICP torch. A quantification procedure is proposed for direct solid analysis without the use of certified reference materials. Under the proposed electrolysis conditions, up to 60 solid samples can be analyzed per hour. Results obtained for alloying elements in austenitic and ferritic stainless steels were in good agreement with the certified values.
Aluminum Spectrophotometry Electrochemical dissolution Multielement

"Flow Injection Extraction-spectrophotometric Determination Of Manganese(VII) With Benzyltributylammonium Cations"
Anal. Chim. Acta 1992 Volume 270, Issue 1 Pages 213-215
D. Thorburn Burns*, S. A. Barakat, M. Harriott and M. S. El-Shahawi

Abstract: Steel (500 to 2000 µg) was dissolved in H2SO4 - H3PO4 (35 ml), followed by oxidation with HNO3 (2 ml) and boiling to expel nitrous acid fumes; any carbides remaining were evaporated. To the cooled solution water (50 ml) and concentrated HNO3 (5 ml) were added. The solution was boiled for 2 min and 0.5% KIO3 (10 ml) was added followed by boiling for a further 4 min. The solution was then cooled and transferred to a 100 mL volumetric flask and made up to volume with water. The peak height was measured using the flow injection system. Sample was injected into a carrier stream of phosphate buffer (pH 6) which was merged with aqueous NH4F solution (0.70 mL min-1), mixed with aqueous 0.10% benzyltributylammonium chloride solution (0.67 mL min-1) in a coil (25 cm x 0.5 mm). The aqueous phase was mixed with CHCl3 and passed through an extraction coil (150 cm x 0.5 mm) followed by a phase separator. The organic phase was used for the spectrophotometric determination of the Mn(VII) complex at 548 nm. The calibration graph was rectilinear from 0 to 25 µg mL-1 and the detection limit was 0.91 g mL-1 of Mn, (for 250 µL injections). The method was also applied to the determination of Mn in copper - nickel alloy. A flow injection manifold has been developed for the spectrophotometric determination of manganese(VII) at 548 nm after extraction into chloroform of the ion-associated, benzyltributylammonium permanganate. The carrier stream was a pH 6 buffer containing 10%(w/v) ammonium fluoride and the reagent stream was 0.10%(w/v) benzyltributylammonium chloride. The injection rate was 20 h-1. The calibration graph is linear up to 25 µg mL-1 and the detection limit (3 x baseline noise) is 0.91 µg mL-1 Mn(VII), based on 250 µL injection volumes The system has been applied to the determination of manganese in steels and a cupro-nickel alloy.
Manganese(7+) Sample preparation Spectrophotometry Sample preparation Organic phase detection Ion pair extraction Phase separator

"Flow Injection Extraction-spectrophotometric Determination Of Chromium(VI) With The Benzyltributylammonium Cation"
Anal. Chim. Acta 1993 Volume 272, Issue 1 Pages 135-138
S. A. Barakat, D. Thorburn Burns* and Michael Harriott

Abstract: Steel samples were decomposed with 20% H2SO4 and HNO3 (plus sodium nitrite for samples rich in Mn) and, after dilution and addition of 0.05 M Ce(IV) and H2SO4 to a portion, Cr(VI) was determined by extraction of benzyltributylammonium dichromate from dilute H2SO4 medium into CHCl3 in a flow injection system (diagram given) for spectrophotometry at 365 nm. The calibration graph was rectilinear up to 20 µg/ml of Cr and the detection limit was 0.5 µg/ml. The RSD (n = 10) was 0.7% for 15 µg/ml. The method showed good selectivity and the results obtained on four reference steels were close to certified values.
Chromium(VI) Sample preparation Spectrophotometry Sample preparation Extraction Reference material

"Flow Injection Spectrophotometric Determination Of Molybdenum(VI) By Extraction With Quinolin-8-ol"
Anal. Chim. Acta 1993 Volume 281, Issue 3 Pages 607-610
D. Thorburn Burns, M. Harriot and P. Pornsinlapatip

Abstract: Samples (5 ml) were mixed with 7 mL of 2.4% HCl/1.5% KCl (50:9) buffer of pH 0.85, 5 mL of 1% quinolin-8-ol solution in dilute H2SO4 (pH 0.85) and diluted to 20 mL with dilute H2SO4 of pH 0.85 to form the Mo(VI) - quinolin-8-ol chelate. Portions (250 µL) of the resulting solution were injected into a stream (0.7 ml/min) of dilute H2SO4 of pH 0.85 which passed through a mixing coil (0.75 m x 0.8 mm i.d.) before merging with a stream (0.82 ml/min) of CHCl3 and entering an extraction coil (1.5 m x 0.8 mm i.d.). The phases were separated in a membrane phase separator fitted with a PTFE membrane (1 µm pore size) and the absorbance of the organic phase was measured at 385 nm. The calibration graph was linear from 0.11 (detection limit) to 10 µg/ml of Mo and the RSD at 5 µg/ml was 1.7%. Equal and 2.5-fold amounts of V(V) and W(VI), respectively, did not interfere in the determination of 1.25 µg of Mo, but a 5-fold amount of Sn(II) did. The method was applied to samples of British Chemical Standard steels containing 300-800 µg of Mo (preparation details given); results agreed well with certified values.
Molybdenum(VI) Spectrophotometry Sample preparation Extraction 8-Hydroxyquinoline Reference material Teflon membrane Phase separator Interferences

"Kinetic Determination Of Cobalt And Nickel By Flow Injection Spectrophotometry"
Anal. Chim. Acta 1993 Volume 283, Issue 1 Pages 476-480
M. A. Z. Arruda, E. A. G. Zagatto* and N. Maniasso

Abstract: For the simultaneous determination of Co and Ni, the slower decomplexation rate for the Ni/citrate complex as compared with the Co/citrate complex was exploited. A 500 µL plug of sample solution was transported by a carrier stream of 0.01 M HCl and merged with 0.1 M sodium tetraborate within a reactor coil. The stream was then treated with 0.01 M sodium citrate and 1 mM 4-(2-pyridylazo)resorcinol (PAR) within a 400 cm coil before the addition of 0.1 M Na2EDTA/0.01 M Na4P2O7 masking solution and passage through a further coil before spectrophotometry at 520 nm to give the sum of Co and Ni. By using a 100 µL sample plug and a 1 cm coil for the PAR reaction, the signal corresponded chiefly to the Co in the sample. For Co in tool steel, the system was simplified by increasing the flow rates and using a short reaction coil. Steel samples were decomposed by aqua regia at 160°C and the resulting solution were diluted with water and then diluted 1000-fold with 0.01 M HCl for analysis. In the determination of 2-5.24 mg/l of Co and 0.12-0.95 mg/l of Ni in solution of alloys, the RSD were 1-3.2% and 0.9-7%, respectively (n = 5). Results agreed well with those obtained by ICP-AES.
Cobalt Nickel Sample preparation Spectrophotometry Kinetic Method comparison

"Synergetic Catalytic Effect Of Molybdate And Tungstate On The Hydrogen Peroxide-iodide System And Its Analytical Applications"
Anal. Chim. Acta 1995 Volume 303, Issue 2-3 Pages 241-246
Wang Jianhua* and He Ronghuan

Abstract: Steel samples (200 mg) were dissolved in 20 mL of 50% H2SO4 with heating, and after the addition of HNO3 boiled to remove nitrogen oxides. After the further addition of 100 mL of water, 4 mL of 30% H2O2 was added and the solution diluted to 200 mL with water. Fe(III) was selectively adsorbed using an anion-exchange column as described by Papadopoulos and Zotou (Mikrokim. Acta, 1992, 105, 203) and Mo(VI) and W(VI) eluted with NaOH-NaCl solution and the eluate adjusted to a pH of 3 with HCl. Portions of 40 µL were injected into a carrier stream (2.4 ml/min) of 0.1% starch solution of pH 3, and Mo(VI) and W(VI) reacted in a 300 mm reaction coil with 3 ml/min flows of 10 mM KI and 9.7 mM H2O2 adjusted to a pH of 3, and stop-flow detection at 589 nm. Using a compensation model (details given) calibration graphs at 30 s and 45 s were linear over the range 0-1.1 µg/ml Mo(VI) and 0-2 µg/ml W(VI). At 40-150 µg/g Mo and W, recoveries of 97.3-102.8% (Mo) and 96.5-102.1% (W) were obtained with RSD of 2.1-2.9% and 2.3-3.4%, respectively. Satisfactory analytical performance was maintained at Mo:W concentration ratios in the range 0.1:1 to 4:1.
Molybdenum Tungsten Spectrophotometry Interferences Stopped-flow Catalysis

"Flow Injection Spectrophotometric Determination Of Copper Using Bis(cyclohexanone)oxalyldihydrazone"
Anal. Chim. Acta 1995 Volume 304, Issue 1 Pages 97-100
N. Chimpalee, D. Chimpalee, S. Srithawepoon, T. Patjarut and D. Thorburn Burns*

Abstract: A sample (250 µL) was injected into a water carrier stream (1.35 ml/min) which was then sequentially merged with streams (1.35 ml/min) of 27% citric acid solution, 37% ammonia solution and 0.18% bis(cyclohexanone)oxalyldihydrazone solution then passed through a reaction coil (4 m x 0.8 mm i.d.) to a detector cell with detection at 600 nm. The calibration graph was linear up to 20 µg/ml Cu; the detection limit was 1.3 µg/ml and RSD was 0.92% (n = 10). The method was applied to the determination of Cu in steels, copper-based alloys and pig feeds and to copper monitoring in an alkaline scale-removal process.
Copper Spectrophotometry Complexation

"Multicommutation In Flow Analysis. 2. Binary Sampling For Spectrophotometric Determination Of Nickel, Iron And Chromium In Steel Alloys"
Anal. Chim. Acta 1995 Volume 308, Issue 1-3 Pages 397-405
Patricia B. Martellia, Boaventura F. Reisb,*, Eloisa A. M. Kronkab, Henrique Bergamin b, Mauro Kornc, Elias A. G. Zagattob, Jos&eacute;Luis F. C. Limad and Alberto N. Araujod

Abstract: FIA methods are described for the spectrophotometric determination of (i) Ni with dimethylglyoxime as chromogenic reagent and (ii) Fe and Cr with salicylic acid and diphenylcarbazide as chromogenic reagents, respectively, in acid solutions of steel alloys. Control software written in QuickBasic 4.6 controlled all steps involved in the multicommutation processes. Samples and reagents were inserted into the carrier stream as a series of slugs. For i seven slugs of sample solution of 5.6 µL each were inserted into a carrier stream (28 µL/s) of 3% triethanolamine in 0.5 M NaOH. Ten slugs of 10% potassium peroxodisulfate solution (5.6 µL) and 14 slugs of 1% dimethylglyoxime solution (98.4 µL) were added. The mixture was propelled to the detection cell where the absorbance was measured at 460 nm. For ii a carrier stream (2 ml/min) of 0.5 M HCl was used with 2.8% salicylic acid or 0.06% diphenylcarbazide. Sample slugs were inserted alternatively with reagent slugs to give sample/reagent ratios of 1:1. The consumption of reagent for each determination was 80 µL for Fe and 26 µL for Cr. The detector was operated at 540 nm for the determination of both Fe and Cr. The methods were tested by analyzing various steel alloy and comparing the results with those obtained by AAS or ICP-AES. The sampling frequency was 60 samples/h for Ni determinations and 110 samples/h for Fe and Cr determinations.
Chromium Iron Nickel Spectrophotometry Commutation Computer Method comparison Chromogenic reagent

"Direct Spectrophotometric Determination Of Chromium By Microwave-oven Induced Flow Injection Analysis"
Anal. Chim. Acta 1998 Volume 374, Issue 1 Pages 61-66
Xiaoyuan Wu, Hui Zhao, Xingguo Chen, Zhide Hu*, Zhengfeng Zhao and Martin Hooper

Abstract: Two sensitive flow injection methods were developed for the determination of traces of Cr(VI), based on the very efficient microwave-accelerated reactions of Cr2O72- with dibromocarboxyarsenazo (DBM-AsA, in System 1) and dibromo-o-carborylchlorophonazo (DBOK-CPA, in System 2). The reactions are followed spectrophotometrically by measuring the decrease in the absorbance of DBM-AsA at 535 nm or DBOK-CPA at 556 nm. The sampling frequency for both systems is 40 h-1. The calibration graphs are linear at 1.62-27.0 µg mL-1, and 0.40 and 10.80 µg mL-1 for Systems 1 and 2, respectively. The respectively. detection limits are 0.087 and 0.10 µg mL-1. The methods were applied to determine traces of Cr in a steel sample and electroplating solutions with satisfactory results.
Chromium(VI) Spectrophotometry Microwave Heated reaction Indirect

"Unsegmented Flow Analysis With Ion-selective Electrodes By Use Of A Large-volume Wall-jet Cell. Continuous Electrode Reactivation In The Determination Of Fluoride And Chloride"
Talanta 1991 Volume 38, Issue 12 Pages 1393-1398
Jiri Lexa, Karel Stul&iacute;k

Abstract: The simple design and potentiometric applications of the cell are presented. Properties are demonstrated by using the method to determine fluoride and chloride ion in steel corrosion products. Detection limits are 63 nM-fluoride ions and 0.23 µM-chloride ions, both are much lower than for common batch measurements. Measurements of 150 h-1, with no change in reliability, can be made.
Chloride Fluoride Electrode Potentiometry

"Investigations For The Determination Of Tin By Flow Injection Hydride-generation Atomic Absorption Spectrometry"
Talanta 1992 Volume 39, Issue 9 Pages 1097-1105
Bernhard Welz*, Marianne Schubert-Jacobs and Tiezheng Guot,

Abstract: Flow injection hydride-generation AAS for tin was carried out using a light source set at 224.6 nm. Variable pre-peaks were frequently observed (attributed to gradual diffusion of Sn present in the silica of the atomizer tube) but were eliminated by including 10% H in the purge gas. In flow injection systems, pre-peaks can be limited to a single, well separated peak before the first signal in a sequence of measurements by continuous generation of H from the acid carrier stream and NaBH4. The best results were achieved with saturated H3BO3 - 0.1 M HCl as carrier solution and 0.4% NaBH4 - 0.05% NaOH solution as the reducing mixture added to the carrier before sample injection. Sensitivity was improved by including 1% oxygen in the purge gas. Tin was determined in low alloy steels in the range 0.008 to 0.1% and results were in close agreement with certified values. A plot of absorbance vs. Sn concentration. was linear for both acidic steel digests and matrix-free reference materials. When 0.4% NaBH4 was used as reductant, sensitivity and freedom from interferences were improved. It could be shown that the pre- or double peaks which are frequently observed in the determination of tin by hydride generation atomic absorption spectrometry are not due to reagent contamination or memory effects. Rather they originate from the silica material used to make the quartz tube atomizer. At elevated temps. the tin diffuses to the surface and it can be volatilized and atomized only in the presence of hydrogen. The height of the pre-peak depends, among other things, on the time for which the quartz tube atomizer has been at a high temperature without hydrogen. The pre-peaks disappear when argon with 10% (v/v) hydrogen is used as the purge gas. In flow injection the pre-peaks can be separated in time from the anal. signal by using a program in which hydrogen is generated by reaction of sodium tetrahydroborate reductant solution with the acid carrier prior to the injection of the sample. Also investigated was the influence of the acid and sodium tetrahydroborate concentration. on sensitivity and freedom from interferences. Best results were obtained when a saturated boric acid solution containing 0.1 M hydrochloric acid was used for standards, samples and carrier solution, and a 0.4%(m/v) sodium tetrahydroborate solution with 0.05%(m/v) sodium hydroxide as the reductant. Under these conditions tin could be determined accurately in the range 0.008-0.1% in low alloy steel standard reference materials, with matrix-free standard solutions for calibration.
Tin Spectrophotometry Sensitivity Interferences Reference material

"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 Spectrophotometry Stopped-flow Indirect Standard additions calibration Kinetic Interferences

"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 Spectrophotometry Mixing chamber Review Standard additions calibration Well stirred mixing chamber Optimization

"Flow Injection Determination Of Oxidants With Leuco-thionine Blue"
Analyst 1988 Volume 113, Issue 7 Pages 1057-1060
armen Martinez-Lozano, Tom&aacute;s P&eacute;rez-Ruiz, Virginia Tom&aacute;s and Encarnaci&oacute;n Yag&uuml;e

Abstract: Sample solution (85 µL) is injected into the flow injection system and mixed with leuco-thionine blue solution [prepared by irradiation of thionine blue (C. I. Basic Blue 25) in aqueous EDTA] and buffer solution (pH 4.5 to 5.5) in a reaction coil (100 cm). Flow rates of all solution are 0.74 mL min-1. The absorbance of the solution is measured at 670 nm. Results for determination of IO4-, Cr(VI), Fe(CN)63- and V(V) are presented. Limits of determination ranged from 48 to 0.108 µM. The method was applied in the determination of Cr and V in steels, V in petroleum products and Fe(CN)63- in photographic solution, and in the separation of Cr(VI) - Cr(III) mixtures.
Periodate Chromate Vanadium(V) Ferricyanide Spectrophotometry Redox

"L-Cysteine As A Reducing And Releasing Agent For The Determination Of Antimony And Arsenic Using Flow Injection Hydride-generation Atomic Absorption Spectrometry. 2. Interference Studies And The Analysis Of Copper And Steel"
Analyst 1993 Volume 118, Issue 11 Pages 1425-1432
Bernhard Welz and Marcella Sucmanov&aacute;

Abstract: The method described in Part I (see abstract number 5D157) was used for the determination of Sb and As in Cu and steel. Cu was digested by cautious treatment with 7 and 14 M HNO3 and the digest was diluted with water and mixed with 10% L-cysteine solution Steel was heated with 10 M HCl followed by sequential treatment with 14 and 7 M HNO3, H2O2 and 7 and 14 M HNO3. The digest was evaporated to near-dryness and the peroxide-acid sequence was repeated 4 times at 135°C. The final residue was dissolved in 7 M HNO3 before the addition of 5% L-cysteine solution The resulting sample solution were diluted with water before analysis. Tolerance limits for Ni(II) and Cu(II) were 250 and 500 mg/l, respectively, in the determination of Sb. The corresponding limits in the determination of As were 200 mg/l and >1000 mg/l. However, if KI was used as reductant instead of L-cysteine, only 100 mg/l could be tolerated. In the analysis of standard reference materials, results agreed with certified values.
Antimony Arsenic Sample preparation Spectrophotometry Interferences Reference material

"Simultaneous Automatic Determination Of Trace Amounts Of Copper And Cobalt By Use Of A Flow-through Sensor And First-derivative Spectrometry"
Analyst 1997 Volume 122, Issue 1 Pages 85-88
Elisa Vereda, Angel Rios and Miguel Valcarcel

Abstract: A stream (0.9 ml/min) of sample solution merged with a reagent stream (0.35 ml/min) of 0.025% pyridoxal-4-phenylthiosemicarbazone in aqueous 30% DMF, passed through a reactor (140 cm x 0.5 mm i.d.), merged with a stream (0.3 ml/min) of 3 M HClO4 then passed through 60 cm and 35 cm reactors. The mixture then passed through a flow cell, packed with Sep-Pak C18 sorbent to retain Co(II) and Cu(II) complexes. When the sorbent was saturated (35 s), the first-derivative absorption spectrum was recorded from 200-500 nm using a diode-array detector. Co(II) was determined at 292 nm, and Cu(II) at 420-442 nm. The calibration graphs were linear from 0.3-6 and 0.1-15 µg/ml Co(II) and Cu(II), respectively, and detection limits were 0.03 µg/ml for both analytes. The RSD (n = 11) were 2% for 2 µg/ml Co(II) and 0.9% for 5 µg/ml Cu(II). The throughput was 35 samples/h. The effects of interferents were investigated (results tabulated). The method was applied to steel.
Cobalt(II) Copper(II) Spectrophotometry Spectroscopy Sensor Preconcentration Simultaneous analysis C18 Complexation Interferences

"New Concept For Hydride-generation Technique: Electrochemical Hydride Generation"
J. Anal. At. Spectrom. 1993 Volume 8, Issue 3 Pages 397-401
Andreas Brockmann, Christiane Nonn and Alfred Golloch

Abstract: A miniaturized continuous-running cell with Pt anode and cathode compartments separated by a Nafion membrane and 2 M H2SO4 as anolyte plus diluted HCl or H2SO4 as catholyte were used. The anolyte was circulated after separation of liberated O and analyte hydrides were separated from the catholyte by a membrane gas - liquid separator. The very low catholyte flow enabled lower consumption of costly high-purity acids. The flow injection analytical system required sample volume of 100 µL. Tests with five reference materials (steels) indicated that Cr, Ni, Co and Cu did not interfere significantly with determination of As.
Arsenic Spectrophotometry Electrochemical product conversion Interferences Reference material Nafion membrane

"Determination Of Trace Elements In Unalloyed Steels By Flow Injection Inductively Coupled Plasma Mass Spectrometry"
J. Anal. At. Spectrom. 1995 Volume 10, Issue 6 Pages 449-453
Aurora G. Coedo and Teresa Dorado

Abstract: Steel (250 mg) was treated with 7 mL 65% HNO3, 200 µL 40% HF and 3 mL water and the mixture was digested in a microwave oven (program details given). The oven was cooled, the contents were transferred to a calibrated flask and 2.5 µg each of Be, Tl and Rh (internal standards) were added. The solution was diluted to 50 mL with 1% HNO3 and a 250 µL portion of the solution was pumped into the nebulizer (2.8 ml/min), mixed with the nebulizer gas (1.1 ml/min) and analyzed by ICP-MS (operating conditions given). The RSD was 3% for all analytes at concentrations 1 µg/g. The method was applied to the analysis of two pure Fe reference materials (BCR CRM 097 and NIST SRM 365). Results agreed well with certified values.
Trace elements Mass spectrometry Sample preparation Internal standard Reference material

"Determination Of Trace Amounts Of Boron By Microwave Plasma Torch Atomic-emission Spectrometry Using An Online Separation And Preconcentration Technique"
J. Anal. At. Spectrom. 1996 Volume 11, Issue 5 Pages 331-337
Qun Jin, Hanqi Zhang, Feng Liang, Wenjun Yang and Qinhan Jin

Abstract: Separation from interfering cations was effected by passing the sample solution at 2.5 ml/min through a column of strong cation-exchange resin. The solution was then merged with a stream of aqueous 1 M NH3 (2.5 ml/min) and passed through an anion-exchange pre-concentration column. Elution was effected with 1 M HCl at 1.5 ml/min, and the eluate was introduced into the microwave plasma torch via a pneumatic nebulizer and a desolvation system. The effects of observation height, microwave forward power, eluent composition, flow rates and presence of foreign ions were investigated. The detection limit was 1.8 µg/l, and calibration graphs were linear up to 40 mg/l. The method was applied to steel after digestion with HCl/HNO3 (3:1).
Boron Ion exchange Sample preparation Spectrophotometry Preconcentration Optimization Interferences Resin

"Study Of The Application Of Air-water Flow Injection Inductively Coupled Plasma Mass Spectrometry For The Determination Of Calcium In Steels"
J. Anal. At. Spectrom. 1996 Volume 11, Issue 11 Pages 1037-1041
A. G. Coedo, M. T. Dorado, I. Padilla and F. J. Alguacil

Abstract: Steel shavings (0.25 g) and 100 ng Sc (internal standard) were transferred to a PTFE microwave digestion vessel, together with 5 mL HCl, 2 mL HNO3 and 0.1 mL HF, the vessel was sealed and subjected to 360 W of microwave power for 30 min. The solution was transferred to a PTFE beaker, mixed with 1 mL HF and 0.75 mL H2SO4 and evaporated to white fumes. This step eliminates isobaric interference from 12C16O2 and 28Si16O. The liquid was diluted to 50 mL. The Fe(III) matrix was removed from 20 mL by electrolysis at a Hg cathode. Portions (0.2 ml) were injected into the air segment (1.8 ml/min) of an air-0.5% HNO3 carrier by valve programming and the carrier was transported directly into the ICP mass spectrometer for measurement of the 44Ca peak (to avoid Ar interference with the 40Ca peak). Sensitivity was increased by a factor of three compared with injection into a continuous-flow of aqueous carrier. Calibration graphs were linear for 20-200 ng/l of Ca(II) solutions in 1.5% H2SO4 and containing 2 ng/l of Sc. The detection limit was 3 ng/ml, corresponding to 0.6 ppm Ca in the sample. At the detection li the RSD (n = 5) was 15%, decreasing to 1% above 30 ng/ml. The method was applied to the analysis of four reference steels (12-28 ppm Ca).
Calcium-44 Sample preparation Mass spectrometry Reference material Interferences

"Use Of Boric Acid To Improve The Microwave-assisted Dissolution Process To Determine Fluoride Forming Elements In Steels By Flow Injection Inductively Coupled Plasma Mass Spectrometry"
J. Anal. At. Spectrom. 1998 Volume 13, Issue 10 Pages 1193-1197
Aurora G. Coedo, M. Teresa Dorado, Isabel Padilla and Francisco J. Alguacil

Abstract: The applicability of FI-ICP-MS combined with microwave sample digestion for the simultaneous determination of trace amounts of La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu in iron and steel samples was studied. The use of hydrofluoric acid in the sample dissolution process produced nearly invisible insoluble particles with the REEs, leading to erroneous quantification of these elements. The addition of boric acid, complexing HF, solved this problem. By monitoring the transient signals produced by the FI microsampling system, it was possible to evaluate the effectiveness of the sample dissolution procedure. Severe depressive matrix effects caused by the sample matrix were encountered when the signals were compared with those from HNO3 solutions; in contrast, no effects were observed with the addition of boric acid. A highly alloyed steel, stainless steel certified reference material JK 37 (Sandvik Steel), was used to evaluate the effectiveness of the dissolution procedure and to develop the method. The limits of quantification (LOQ) calculated from 10.sqroot.s ranged between 0.008 µg g-1 for Lu and 0.040 µg g-1 for Nd. The relative standard deviation for all the analytes was better than 3% (n=4) for concentrations >10 times the LOQ.
Lanthanum Cerium Praseodymium Neodymium Samarium Europium Gadolinium Terbium Dysprosium Holmium Erbium Thulium Ytterbium Lutetium Metals, lanthanides Mass spectrometry Sample preparation Reference material Interferences

"Hydride-generation Atomic Absorption Spectrometry Coupled With Flow Injection Analysis"
Anal. Chem. 1985 Volume 57, Issue 7 Pages 1382-1385
Manabu Yamamoto, Makoto Yasuda, and Yuroku Yamamoto

Abstract: Flow injection analysis was combined with the gas-segmentation method described by Skeggs (Am. J. Clin. Pathol., 1957, 28, 311) for the determination of As, Sb, Bi, Se and Te. On synthetic samples the coefficient of variation were between 0.5 and 0.8% (n = 10) with detection limits between 0.04 and 0.3 ng. The results on NBS steel, wheat and rice flour, orchard leaves and coal fly ash were close to certified values and the differential determination of As and Sb in thermal water was possible. Tolerance limits for diverse ions are listed.
Arsenic Antimony Bismuth Selenium Tellurium Spectrophotometry Reference material Segmented flow

"Isotope Dilution Analysis For Flow Injection ICP-MS Determination Of Microgram Per Gram Levels Of Boron In Iron And Steel After Matrix Removal"
Anal. Chem. 1996 Volume 68, Issue 6 Pages 991-996
Aurora G. Coedo, Teresa Dorado, Bernardo J. Fernandez, and Francisco J. Alguacil

Abstract: Steel or Fe (0.25 g) was mixed with HCl, HNO3, H2SO4 and water in a high-pressure digestion vessel and dissolved using a microwave oven. A 10B spike solution was added (250 ng B) and the solution was evaporated to form solid salts, which were redissolved in water. The solution was extracted with acetylacetone/CHCl3 (1:1) at pH 1.4, the organic phase was discarded, and the extraction procedure was repeated on the aqueous phase. The aqueous layer was mixed with 1 mL HNO3, the solution was evaporated to 2 mL and diluted to 5 mL with water. The resulting test solution corresponded to 50 mg/ml sample, with the total B and Fe contents 1 µg/ml. Flow injection sampling minimized problems arising from the total salt concentration. The ICP-MS detection limit was 0.02 µg/g and the RSD values for concentrations 10 times this limit were 1% (n = 4). Good accuracy was obtained for eight Fe reference materials with B contents 10 µg/g.
Boron Mass spectrometry Sample preparation Reference material Interferences Matrix removal

"Flow Injection Extraction-spectrophotometric Determination Of Permanganate With The Triphenylsulfonium Cation"
Fresenius J. Anal. Chem. 1992 Volume 344, Issue 3 Pages 131-132
D. Thorburn Burns Contact Information, S. A. Barakat, M. S. El-Shahawi and M. Harriott

Abstract: Sample solution was injected into a carrier stream (0.7 mL min-1) of buffer solution (pH 6) containing 10% NH4F which merged sequentially with a stream (0.69 mL min-1) of aqueous 0.1% triphenylsulfonium chloride and a stream (0.7 mL min-1) of CHCl3. The mixture passed through an extraction coil (150 cm x 0.5 mm) and a phase separator and the absorbance of the organic phase was measured at 548 nm. The calibration graph was rectilinear up to 40 µg mL-1 of MnO4-; the detection limit was 1.1 µg mL-1. Sample throughput was 20 h-1. The method was used in the analysis of steel and alloys. Permanganate can be determined spectrophotometrically at 548 nm after flow injection extraction into chloroform of the ion-associated triphenylsulfonium permanganate. The carrier stream was a pH 6 buffer containing 10% (w/v) ammonium fluoride and the reagent stream was 0.10% (w/v) triphenylsulfonium chloride. The injection rate was 20 h-1. The calibration graph is linear up to 40 µg mL-1 and the detection limit is 1.10 µg mL-1 Mn(VII), based on injection volumes of 250 µL. The system has been applied to the determination of manganese in steels and a cupro-nickel alloy.
Permanganate Spectrophotometry Sample preparation Extraction Phase separator Organic phase detection

"Investigation Of The Automated Determination Of Arsenic, Antimony And Bismuth By Flow Injection Hydride Generation Using In Situ Trapping On Stable Coatings In Graphite-furnace Atomic Absorption Spectrometry"
Fresenius J. Anal. Chem. 1996 Volume 356, Issue 7 Pages 435-444
H. O. Haug and Y. -p. Liao

Abstract: The elements were determined in low-alloy steel reference materials, which were dissolved in aqua regia at 90°C over 3 h. Solutions were diluted to 100 mL with 1 M HNO3 and portions treated with 1% L-cysteine in 0.1 M HNO3 for flow injection hydride generation by reaction with alkaline 0.5% NaBH4 and use of 0.1 M HCl (2.8 ml/min) as carrier solution. The liberated hydrides were measured by GFAAS trapping adsorption in situ on to Zr-coated graphite tubes (or Ir-coated for Sb). Hydride introduction was at 700-750°C (As), 450°C (Sb) or 300-400°C (Bi) and atomization at 2100-2400°C (As) or 2100°C (Sb or Bi) and measurements were at 197.2 (As), 217.6 (Sb) or 223.1 nm (Bi) with Zeeman background correction (As and Sb) or with no correction or deuterium correction (Bi). Hydride generation efficiencies were >98% for Sb and >95% for Bi and respective trapping efficiencies were 91% and 56%. Detection limits were 0.015, 0.010 and 0.027 ng for As, Sb and Bi hydrides, respectively, and corresponding precisions of determination were
Arsenic Antimony Bismuth Sample preparation Spectrophotometry Volatile generation Reference material Volatile generation

"Use Of Microwave Plasma Torch Atomic Emission Spectrometry For The Determination Of Silicon"
Fresenius J. Anal. Chem. 1997 Volume 357, Issue 4 Pages 384-388
Feng Liang, Hanqi Zhang, Q. Jin, Daxin Zhang, Y. Lei

Abstract: Standard steel samples were dissolved with 30% H2O2/HCl then mixed with 35 mL water. The resultant solution was heated until H2O2 was completely decomposed. Standard Al samples were digested similarly without H2O2. Mineral water was analyzed directly. A dual-pump flow injection system was used for online separation. Samples (300 µL) were carried with water or HCl into a nebulizer through a glass cation-exchange resin column (4 cm x 4 mm i.d.). A schematic of the flow injection system is given. The desolvation system was similar to one described previously (Zhang et al., J. Anal. Atom Spectrom., 1994, 9, 851). The sample was automatically carried into the microwave plasma torch. The operating conditions of the system are tabulated. Detection limit was 10.8 ng/ml silicon when Ar was both carrier and support gas; RSD was 4.2% (n=11) for determination of 1 µg/ml silicon.
Silicon Ion exchange Spectrophotometry Sample preparation Resin

"Determination Of Copper By Anodic Stripping Voltammetry On A Glassy Carbon Electrode Using A Continuous-flow System"
Fresenius J. Anal. Chem. 1997 Volume 357, Issue 6 Pages 624-628
J. F. van Staden and M. Matoetoe

Abstract: Samples were analyzed using a continuous-flow voltammetric flow-through trace analyzer. system with a Perspex wall-jet flow cell (5 ml). Three electrodes were positioned in the cell; a 3 mm diameter glassy C disc working electrode, a glass C rod auxiliary electrode and a Ag/AgCl/KCl reference (schematic of cell given). The supporting electrolyte was 1 M HNO3 and the following conditions applied: 5 min deposition time, -400 mV deposition potential, -400 mV to +400 mV stripping range, 150 mV pulse amplitude, 5 s rest time, 1 ml/min flow rate (during deposition, otherwise O), 10 mV/s scan rate and ~10 min deaeration time. The detection limit was 0.56 µg/l Cu. An accuracy of 0.09±0.005% was obtained with analysis of a CRM of low alloy steel containing 0.09±0.004% Cu. The method was applied to various fresh water samples; RSD (n = 6) was
Copper Voltammetry Electrode Electrode Flowcell Reference material

"Flow Injection Spectrophotometric Determination Of Molybdenum And Vanadium With Carminic Acid In The Presence Of Cetyltrimethylammonium Bromide"
Microchim. Acta 1995 Volume 118, Issue 3-4 Pages 203-211
Tom&aacute;s P&eacute;rez-Ruiz, Carmen Mart&iacute;nez-Lozano, Virginia Tom&aacute;s and Concepti&oacute;n Paredes

Abstract: Portions (85 µL) of 4 mM carminic acid solution of ~ pH 4 were injected into streams (1.2 ml/min) of Mo or V [V was pre-reduced to V(IV) with 1% ascorbic acid] solutions. The resulting stream was merged with a stream (1.2 ml/min) of 4 mM cetyltrimethylammonium bromide, and then with a stream (1.2 ml/min) of 0.5 M acetate buffer of pH 4.6. After passing through a reaction coil (100 cm x 0.5 mm i.d.) where the flow was stopped for 60 s, the solution passed to a 18 µL flow cell for measurement of absorbance at 585 and 575 nm for Mo and V, respectively. The calibration graphs were linear for 0.76-28.8 and 0.3-9.1 µg/ml Mo and V, respectively, and the corresponding detection limits were 0.33 and 0.16 µg/ml; the corresponding RSD were 0.68-0.82% and 1.1-1.4% (n = 10). Sample throughput was 33/h. Tolerance levels of interfering ions are tabulated. The method was applied to steel, pharmaceuticals (multivitamins) and petroleum products (sample preparations described).
Molybdenum Vanadium Spectrophotometry Sample preparation Stopped-flow Interferences

"Spectrofluorimetric Flow Injection Determination Of Cerium In Carbon And Low Alloy Steels"
Microchim. Acta 1995 Volume 119, Issue 1-2 Pages 49-53
D. Thorburn, Champa D. P. Dangolle and M. Harriott

Abstract: Steel was degreased, dissolved in concentrated H2SO4 and water and the solution was filtered and diluted to 100 mL with water. Portions (250 µL) were injected into a stream (5 ml/min) of aqueous 2.5% hydroxylammonium chloride and carried through a reaction zone (80 cm x 2 mm i.d.) to a flow cell for measurement of fluorescence at 350 nm (excitation at 260 nm). The calibration graph was linear for up to 7 µg/ml Ce. Fe(II) interference was corrected by matrix matching. The RSD was 2% (n = 5) at 3 µg/ml Ce. Sample throughput was 30/h. No detection limit is given.
Cerium Sample preparation Fluorescence Interferences

"Determination Of Boron In Steels By Online Flow Injection Cation Exchange Eliminating Matrix Inductively Coupled Plasma Atomic Emission Spectrometry"
Microchem. J. 1996 Volume 53, Issue 1 Pages 88-92
Huanan Wang, Yao Chen and Jin Wang

Abstract: Steel sample (1-5 g) was digested with 10 mL water, 10 mL HNO3 and 10 mL HCl by heating below the boiling point until dissolution of sample was complete. On cooling, the solution was adjusted to pH 2-3 with NH3 solution and diluted to 100 mL with water at pH 2-3. Portions of the diluted solution were injected into a carrier stream of water (1.6 ml/min) and a flow injection system (schematic shown) and pumped through a cation-exchange column (13 cm x 5 mm i.d.) packed with 732 resin. The matrix Fe ion was retained on the column and the B in the eluate flowed directly to the ICP (operation conditions given) and the absorbance was measured at 249.77 nm by AES. The detection limit was 5 µg/L (corresponding to 0.00001% of B). The method was applied to the analysis of B in four synthetic samples containing 10^-50 mg/ml of Fe and two standard carbon steel samples (40 MnWB) containing 10 and 50 mg/ml of Fe. Results were in good agreement with certified values.
Boron Ion exchange Spectrophotometry Reference material Interferences Resin

"Flow Injection Sample Introduction Into Microwave Plasma"
Microchem. J. 1996 Volume 53, Issue 1 Pages 69-78
Hanqi Zhanga, Dongmei Yea, Jinghong Zhaoa, Jinglei Yua, Ruizhi Mena, Qinhan Jin a, and Defan Dongb

Abstract: The optimization of experimental parameters viz. microwave power, support and carrier gas flow rate, HCl concentration in the sample solution and sample-loop volume was investigated for the detection of fifteen elements (listed) by microwave plasma torch AES (MPT-AES) using a flow injection/pneumatic nebulization (PN) sample introduction system (schematic shown). Under optimized conditions, viz. 60 W microwave power, 650 ml/min carrier gas flow rate, a sample-loop volume of 300 µL and a concentration of 0.05 M HCl in the sample solution the detection limits (DL; 36) obtained for the elements were in the range 5-103 ng/ml. The Dl were almost the same as those obtained with a moderate powered He MPT-AES with an ultrasonic nebulization desolvation system (DS) and are much lower than those obtained by low-powered MPT-AES with PN but without DS as well as moderate-powered Ar CMP with PN-DS. For 0.5-5 µg/nl of added elements RSD were 1.3-5%. Spectral interferences from easily ionizable elements in the matrix were investigated. The method was applied to the analysis of three elements viz. Cu, Ni and Mo in two standard steel samples. Results were in good agreement with certified values.
Copper Nickel Molybdenum Spectrophotometry Nebulizer Reference material Interferences Optimization

"Studies On The Synergic Effects Of Metal Cations On Kinetic Reactions And Their Analytical Applications"
Microchem. J. 1996 Volume 53, Issue 3 Pages 376-384
Jianhua Wang and Ronghuan He

Abstract: The mutual catalytic (synergic) effect between closely related metal cations such as Mo(VI) and W(VI), Ag(I) and Hg(II) and Fe(II) and Sb(III) on different kinetic reaction systems viz. Cr(VI)/iodide, H2O2/iodide and thiourea activated hexacyanoferrate (II)-α,α-bipyridyl, respectively, was studied spectrophotometrically with a stopped-flow-FIA technique. A synergic catalytic coefficient (D) was defined and a method for the simultaneous determination of the components in binary mixtures was proposed (theory and details given) by introducing the coefficient D into the reaction systems to compensate for the deviations of absorbance from additivity. Portions of standard metal ion solutions were injected into a carrier stream of an FIA manifold (schematic shown) and mixed with reagent streams at 3 ml/min in a reaction coil (250 mm) [experimental details given]. The colored complex formed was detected by the method of Wang and He spectrophotometrically. (Anal. Chim., 1993, 276, 419). Under optimized conditions (tabulated), calibration graphs were linear up to 3.7, 3.5, 1.1 and 2 µg/ml, respectively, for Sb(III), Fe(II), Mo(VI) and W(VI) and up to 210 and 195 ng/ml, respectively, for Hg(II) and Ag(I). The method was applied to the analysis of Mo and W in steel, Fe(II) and Sb in a zinc standard and Hg and Ag in tap water. Results agreed well with listed values.
Antimony(3+) Iron(2+) Molybdenum(VI) Tungsten(VI) Mercury(II) Silver(I) Spectrophotometry Kinetic Stopped-flow Optimization

"Investigation Of Stable Coatings For In Situ Trapping Of Selenium And Tellurium In Flow Injection Hydride-generation And Graphite-furnace Atomic Absorption Spectrometry For Automated Determination"
Microchem. J. 1997 Volume 56, Issue 2 Pages 247-258
Y. -p. Liao and H. O. Haug

Abstract: The use of highly stable trapping reagents instead of a Pd modifier for Se and Te determinations was investigated. Best results were achieved with Ir- and Ir/Mg-coated graphite tubes at 550-800°C. With Te some 'carryover effect' was observed at temperatures >600°C. Measurements were performed with use of a spectrAA-800 Zeeman atomic absorption spectrometer at 196 and 214.3 nm for Se and Te, respectively, (other operating parameters are tabulated). The detection limits were ~0.011 and 0.007 ng for Se and Te, respectively, on Ir-coated tubes using a 1 mL sample loop. The method was applied to the determination of Se and Te in low-alloy steel certified reference materials. Flow injection hydride generation and in situ concentration of Se and Te hydrides in graphite furnace atomic absorption spectrometry (AAS) can be automated using a highly stable trapping reagent replacing the Pd modifier. In a systematic study, carbide-forming elements (Zr, Nb, Ta, W) and noble metals (Ir, Ir/Mg, Pd/Ir) were investigated as stable adsorbers which require only a single application. Effective trapping of the Se and Te hydrides is achieved on Ir- and Ir/Mg-coated graphite tubes at 550-800°C. Selenium-75 radiotracer was used to measure the trapping efficiency and about 61% was obtained on an Ir-coated tube. Signal stability and reproducibility were tested over 400 trapping and atomization cycles. The adsorptive ''carryover effect,'' which can lead to errors in absorbance values, was observed with Te, not with Se, at trapping temperatures above 600°C (the ''critical temperature''). The characteristic mass is about 11 pg for Se and 12 pg for Te, and the detection limits (3s) are about 0.011 and 0.007 ng, respectively, on Ir-coated tubes using a 1 mL sample loop. The method was tested by determination of the elements in low-alloy steel certified reference materials. (C) 1997 Academic Press. 31 References
Selenium Tellurium Spectrophotometry Preconcentration Volatile generation Reference material Volatile generation

"Determination Of Tin In Steels By Non-dispersive Atomic-fluorescence Spectrometry Coupled With Flow Injection Hydride Generation In The Presence Of L-cysteine"
Spectrochim. Acta B 1996 Volume 51, Issue 14 Pages 1829-1836
Hengwu Chen, Wei Yao, Dexiu Wu and Ian D. Brindle*

Abstract: Steel (0.1-0.2 g) was dissolved in 10 mL of aqua regia with heating to near-dryness, the residue was dissolved in 5 mL of 6 M HCl, the solution was diluted to 50 mL with 0.1 M HCl, and a 2 mL portion was treated with 4 mL of 2 M HCl and 5 mL of 5% cysteine solution and diluted to 25 mL with water. The sampling and injection (0.5 ml) modes of the flow injection AFS manifold are illustrated; SnH4 was generated with 3-5% NaBH4 solution in 0.2 M NaOH, the presence of cysteine enhancing the AFS signal for Sn by ~30%. The calibration graph was linear over three decades, the detection liwas 1.3 ng, and the RSD (n = 10) at 100 ng/ml of Sn was 1.8%. The results for three standard steels agreed with the certified values.
Tin Fluorescence Sample preparation Reference material Volatile generation Volatile generation

"Analyte Enrichment And Matrix Removal In Flow Injection Analysis-inductively Coupled Plasma-atomic Emission Spectrometry. Determination Of Phosphorus In Steels"
Spectrochim. Acta B 1985 Volume 40, Issue 1-2 Pages 57-62
C. W. McLeod and I. G. Cook, P. J. Worsfold, J. E. Davies and J. Queay

Abstract: Acidified solution of digested steel were injected on to a PTFE column of activated alumina (75 to 120 µm); PO43- was retained on the column, and matrix cations were carried to the nebulizer. The PO43- was then eluted by the injection of 200 µL of 0.5 M KOH, and passed to the ICP plasma for emission measurement at the P I 213.62-nm line. A constant analytical response over an extended period, with PO43- recovery of ~90%, was achieved. The calibration graph was rectilinear for 0 to 50 µg mL-1 of P, and the coefficient of variation was 1.6% at the 20 µg mL-1 level; the limit of detection was 0.6 µg mL-1. Analysis of a standard reference steel gave a value of 0.041% of P compared with the certified value of 0.043%.
Phosphorus Phosphate Sample preparation Spectrophotometry Activated alumina Reference material

"Hydride-generation Flow Injection Using Graphite Furnace Detection - Emphasis On Determination Of Tin"
Spectrochim. Acta B 1992 Volume 47, Issue 5 Pages 701-709
Zhang Li, Susan McIntosh, Glen R. Carnrick and Walter Slavin*

Abstract: Hydride-forming analytes were separated from large volume of matrix by trapping the hydrides on a Pd-coated L'vov platform at low temperature before analysis by AAS. The Pd-treated stabilized-temp. platform furnace was used for in situ trapping and atomization of the analyte, and was at least 80% efficient for As, Bi, Ge, Sb, Se, Sn and Te. The method was tested by determining Sn in steel, river sediment, orchard leaves and bovine liver standard reference materials. The detection limit for Sn was 7 ng l-1, and the coefficient of variation was 31.5% at the 1.0 ng level. Other hydride-forming elements did not interfere.
Arsenic Bismuth Germanium Antimony Selenium Tellurium Tin Spectrophotometry Interferences Volatile generation Reference material Volatile generation

"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 Spectrophotometry Sample preparation Interferences Standard additions calibration Reference material Volatile generation Volatile generation

"Determination Of Trace Amounts Of Phosphorus In Steel After Preconcentration By Carrier Precipitation And Flotation"
Anal. Sci. 1996 Volume 12, Issue 1 Pages 149-150

Abstract: Steel chippings (50-500 mg) were digested with 15 mL HNO3 (1 + 1) and 2 mL HCl, 10 mL 70% HClO4 was added and the solution was heated until fumes of HClO4 commenced. On cooling, the salts were dissolved in 30 mL water and suitable portions of 12.5% aqueous EDTA solutions were added (details given). The pH was adjusted to 8.5 with 3 M aqueous NH3 and the precipitates formed were stirred for 10 min. The solution was diluted to 200 mL with water, 1 mL sodium oleate (6 mg/ml) was added and the mixture was transferred to a flotation cell. Nitrogen gas was passed through the mixture at 9 ml/min for 90 s and the mother liquor was removed by suction. A 5 mL portion of 99.5% ethanol was added and the precipitates were dissolved with 3 x 5 mL 1 M HNO3 and the resulting solution was filtered. The filtrate was mixed with 2 mL 10% ascorbic acid and 400 µL 5 mM Na2S2O3 and diluted to 20 mL with 1 M HNO3. Portions (200 µL) were injected into a flow injection system and detected spectrophotometrically by the method of Tanaka et al. (Ibid., 1994, 10, 669). The calibration graph was linear up to 20 µg phosphate (I). The method was applied to the analysis of I in three standard steel reference samples. Results agreed well with certified values with RSD of 14%.
Phosphorus Spectrophotometry Preconcentration Reference material Precipitation

"Ion-pairing Flow Injection Extraction"
Anal. Proc. 1989 Volume 26, Issue 9 Pages 315-317
M. Harriott, D. Thorburn Burns

Abstract: A flow injection system for automated ion-pairing solvent extraction methods is described and illustrated. The essential components of the system are: (i) a mixing chamber to converge and mix incoming streams; (ii) a segmenter to produce identical alternative segments in the stream; (iii) a phase separator to split the segmented stream into aqueous and organic phases and (iv) a flow cell and detector. The system was applied in the determination of ClO4- in potassium chlorate, Mn and Co in steel and Bi in pharmaceutical preparations (conditions described). Results compared well with stated values.
Perchlorate Manganese Cobalt Bismuth Sample preparation Ion pair extraction Mixing chamber Phase separator Segmented flow

"Simultaneous Determination Of Hydride And Non-hydride Forming Elements By Inductively Coupled Plasma Atomic-emission Spectrometry"
Anal. Proc. 1992 Volume 29, Issue 10 Pages 438-439
Zhang Li, Susan McIntosh and Walter Slavin

Abstract: Arsenic, Se, Sb, Bi, Cd, Cr, Cu, Fe, Mn, Ni and Pb were determined in the NIST environmental standard reference materials steel, coal fly ash, urban particulated and 1643b water by ICP-AES. A Perkin-Elmer FIAS-2000 flow injection system was used for hydride generation (experimental conditions tabulated). The sample solution was split into two streams, one being pumped directly to the nebulizer, the other mixed with HCl and NaBH4 solution in the mixing tubes of the chemifold. After separation, the hydride was swept into the spray chamber through a slightly modified cross-flow nebulizer cap. The hydride was then carried into the plasma together with sample aerosol. Recoveries of 20 µg L-1 of As, Sb and Se and 50 µg L-1 of non-hydride forming elements in river- and seawater standards were >80%.
Arsenic Selenium Antimony Bismuth Cadmium Chromium Copper Iron Manganese Nickel Lead Spectrophotometry Spectrophotometry Reference material FIAS-200 Nebulizer Volatile generation Volatile generation

"Tandem Online Separations: An Alternative Sample Presentation In Atomic Spectrometry For Ultra-trace Analysis"
Acta Chim. Hung. 1991 Volume 128, Issue 4-5 Pages 551-558
Sanz Medel, A.;Menendez Garcia, A.;Fernandez, M.L.;Sanchez Uria, J.E.

Abstract: The coupling of continuous-separation - pre-concentration. devices with atomic spectrometers for ultra-trace elementary analysis is discussed. Simple systems are first outlined, including solid - liquid and liquid - liquid online flow injection extraction coupled with AAS or ICP-AES for Al determination in biological fluids, and continuous gas - liquid separation coupled with ICP-AES for As determination in steel and as an introduction device for S2- determination in a microwave plasma. Examples are then given of tandem configurations in which two different continuous separation units are combined in a single online configuration. A tandem online device based on continuous extraction combined with hydride generation and coupled with ICP-AES for direct As, Sb and I- determinations is described, as well as a continuous liquid - liquid extraction device coupled with ICP-AES or AAS for indirect I- determination. Results show that many sensitivity and selectivity limitations of ultra-trace analysis can be overcome by the use of tandem online separation techniques.
Aluminum Arsenic Spectrophotometry Spectrophotometry Sample preparation Extraction Preconcentration Ultratrace

"Determination Of Cobalt In Acidic Media By Flow Injection Analysis"
An. Quim. 1992 Volume 88, Issue 7-8 Pages 666-669
Sanchez Rojas, F.;Cristofol Alcaraz, E.;Cano Pavon, J.M.

Abstract: A selective method for the FIA photometric determination of Co(II) based on the use of pyridine-2-aldehyde thiosemicarbazone(PAT) as reagent was developed for implementation on a straightforward 4-line flow injection manifold. The FIA method allows the determination of cobalt over the concentration. range 1.8-25 µg mL-1 at a rate of 50 samples h-1. The method is subject to very few interferences as a result of the highly acidic reaction medium used preventing the formation of most of the complexes formed by the reagent and other ions. The FIA method was applied to the determination of cobalt in steels and provided good results.
Cobalt(II) Spectrophotometry Interferences

"Effect Of Continuous Pre-reduction By Heating With Potassium Iodide And Hydrochloric Acid For Determining Total Arsenic By Continuous Hydride Generation - Atomic Absorption Spectrometry Using Sodium Tetrahydroborate Reduction"
Bunseki Kagaku 1983 Volume 32, Issue 6 Pages 357-361
Kumamaru, T.;Matsuo, H.;Ikeda, M.

Abstract: In the determination of total As by reduction - AAS, the sensitivity towards As(V) is ~50% of that towards As(III). The sample solution is therefore pre-treated in a continuous-flow apparatus with 6 M HCl and 40% KI solution at 85°C to reduce As(V) to As(III), which is then reduced by NaBH4 to AsH3 (the absorption of which is measured at 193.7 nm). Interference from, e.g., Sb(III) and Sn(II) can be masked by using 6 M HCl containing 10% of hydroxylammonium chloride. The method has been applied in the analysis of water and of biological and steel standards. The detection limit is 0.3 ng mL-1 of As, and precision (n = 10) is 1% for 20 ng mL-1; ~10 mL of sample solution is required for each determination.
Arsenic, total Spectrophotometry Interferences Heated reaction

"Simple And Rapid Determination Of Micro Amounts Of Nitrogen In Steel By An FIA Method Involving Gas Diffusion Separation And Spectrophotometric Detection"
Bunseki Kagaku 1995 Volume 44, Issue 9 Pages 725-730
Komoda, M.;Ono, A.;Kaneko, S.;Yamane, T.

Abstract: A steel sample is dissolved in HCl, and 1.4 mL of the solution is injected into a carrier stream of water (0.2 ml/min) that then merges with a stream of aqueous 15% tartaric acid/5 M NaOH (0.2 ml/min). The evolved NH3 diffuses through porous PTFE membrane tubing into a stream of aqueous NaClO (0.05% of available Cl)/0.2 M NaOH (0.4 ml/min) in the inner channel that then merges with a stream of 0.5% 1-naphthol solution in aqueous 35% acetone (0.4 ml/min). After passage of the combined streams through a 5 m reaction coil the absorbance is measured at 732 nm. The calibration graph is linear for up to 0.5 µg/ml of N, and down to 2 µg/g in the sample can be determined. Results for reference steels agreed with the certified values, and results for carbon steels agreed with those obtained by the Japanese industrial standard method.
Nitrogen Spectrophotometry Gas diffusion Teflon membrane Reference material Standard method

"Determination Of Trace Amounts Of Nitrogen In Steel By Gas Diffusion/flow Injection Waveguide Capillary-cell Spectrophotometry"
Bunseki Kagaku 1996 Volume 45, Issue 2 Pages 193-199
Aimoto, M.;Komoda, M.;Chiba, K.

Abstract: A steel sample is dissolved in HCl, and 0.5 mL of the solution is injected into a carrier stream of water, which subsequently merges with a stream of 15% tartaric acid solution in 6 M NaOH (both 0.4 ml/min). The combined streams pass through a reaction coil (100 cm x 0.5 mm i.d.) to a 30 cm long gas-liquid-separator, and the NH3 diffuses into a stream of NaClO solution (0.05% of available Cl) in 0.2 M NaOH, which subsequently merges with a stream of 0.5% 1-naphthol solution in aqueous 45% acetone (both 0.3 ml/min). Finally, the combined streams pass through a reaction coil (300 cm x 0.5 mm i.d.) to a waveguide capillary cell (50 cm x 0.68 mm i.d., 1.18 mm o.d.) for absorption measurement at 732 nm. Light from a Xe lamp is selected by a monochromator, focused by a lens, and conducted to the waveguide capillary cell and thence to a photomultiplier tube by optical fibers. The calibration graph is linear for up to ~e;500 ng/ml of N in the sample solution (50 µg/g in the steel). The RSD (n = 3) for 2 µg/g of N was ~e;3%, the results for four certified reference materials agreed with the certified values, and the results for two steels agreed with those obtained by the JIS standard method.
Nitrogen Sample preparation Spectrophotometry Gas diffusion Method comparison Standard method Optical fiber Reference material Phase separator

"Rapid Analysis Of Steel By ICP-AES With Electrolytic Dissolution"
Bunseki Kagaku 1996 Volume 45, Issue 8 Pages 777-782
Kondo, H.;Ono, A.;Uemura, T.;Minami, T.

Abstract: In the PC-controlled continuous-flow system described, the sample is dissolved in HCl (1:1) at constant current and the solution is passed to the ICP automatically; a sample can be analyzed in ~e;1 min. Diagrams of the flow system and electrolysis cell are presented, and operating conditions for both the multichannel and sequential determinations of Fe, Si, Mn, Ni, Cu, Al, Ti and Cr are tabulated. The results for standard steels agreed with the certified values. To determine Ti present in inclusions, the samples were best dissolved at constant potential (0.8-1 V) in HCl/HNO3/H2O (1:1:2). Good agreement with certified values was again obtained.
Iron Silicon Manganese Nickel Copper Aluminum Titanium Chromium Spectrophotometry Computer Reference material Multielement

"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 Spectrophotometry Standard additions calibration Multivariate calibration Simultaneous analysis Interferences

"Simple And Rapid Determination Of Trace Constituents In Iron And Steel By Flow Injection Analysis"
Curr. Adv. Mater. Processes 1997 Volume 10, Issue 3 Pages 676-679
YAMANE Takeshi

Abstract: NA

"Direct Fluorometric And Flow Injection Fluorometric Methods For The Determination Of Trace Phosphorus"
Fenxi Ceshi Xuebao 1998 Volume 17, Issue 3 Pages 77-79
Song Gongwu, Feng Jian

Abstract: Direct fluorometric determination of trace P is based upon the quenching of the fluorescence of rhodamine 6G due to the formation of a nonfluorescent hetero-polynuclear acid of rhodamine-phosphoro-Mo ion-associates. The excitations wavelength is 350 nm, while the maximum emission wavelength is 555 nm. The flow injection fluorometric variant of this method has the advantages of high sensitivity, good selectivity and simplicity. It was satisfactorily employed for the determination of P in Cu alloys, steel, and Mn ores.
Phosphorus Fluorescence Quenching Indirect Ion pair formation

"Chemiluminescence Analysis With Inorganic Coupled Reactions. 4. Determination Of Molybdenum(VI) Ions By Potassium Bromate - Potassium Iodide - Luminol System"
Fenxi Huaxue 1988 Volume 16, Issue 9 Pages 806-808
Zhang, X.R.;Lu, J.R.;Zhu, J.;Zhang, Z.J.

Abstract: Steel (0.5 to 1.5 g) is dissolved in acid, and the solution is adjusted to ~0.1N and passed through a 717 strongly basic anion-exchange column, which is washed with 0.1 M HCl; Mo(VI) is eluted with 1 M HCl. The eluate is adjusted to pH ~4 and mixed with 2.5 mL of 0.1N-KBrO3, 0.5 mL of 0.1 M HCl, water to ~40 ml, 7.5 mL of 0.04 M KI and water to 50 mL. After warming at 30°C for 10 min, the mixture is analyzed in a flow injection system via reaction with 0.5 mM luminol in Na2CO3 - NaOH buffer (pH 12) and measurement of the resulting chemiluminescence. The calibration graph covered the range from 0.01 to 1 mg mL-1 of Mo(VI); the coefficient of variation was ~4%. Citric acid, tartaric acid, EDTA and F- (at mM levels) interfere; other co-existing ions can be tolerated or masked. Results are satisfactory.
Molybdenum Chemiluminescence Ion exchange Heated reaction Interferences

"Determination Of Trace Copper In Ores With Sodium Diethyldithiocarbamate By Flow Injection Extraction-spectrophotometry"
Fenxi Huaxue 1993 Volume 21, Issue 10 Pages 1168-1170
Zhao, H.Z.;Chen, S.Y.;Lin, S.Q.;Li, F.Q.

Abstract: Ore or steel was wetted with water, dissolved in aqua regia and diluted with water. A portion was mixed with 5% EDTA/20% trichloroacetic acid (mixed masking agent), then the solution was adjusted to pH 8.2 and diluted with water. Trace Cu(II) in the solution was determined by the cited method in a FIA system (diagram given) with CCl4 as extractant and 0.2% sodium diethyldithiocarbamate as color reagent. The absorbance was measured at 437 nm. Beer's law was obeyed up to 1.28 µg/ml of Cu. The RSD (n = 11) was 3.5%. The results for five reference standards agreed with their certified values.
Copper Spectrophotometry Sample preparation Reference material Extraction

"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 Spectrophotometry Kinetic Stopped-flow Standard additions calibration Simultaneous analysis

"Simultaneous Determination Of Molybdenum, Tungsten, And Titanium By A Flow Injection - Multiple Standard - Synergistic Coefficient Compensation Method"
Fenxi Huaxue 1996 Volume 24, Issue 3 Pages 274-278
He, R.H.;Wang, J.H.;Wang, Y.B.

Abstract: Sample (40 µL) was injected into a a carrier stream of H2SO4 of pH 1.35 (2 ml/min) in a flow injection system (schematic shown) and mixed sequentially with a streams of ethanolic 0.125 mM salicylfluorone in a reaction coil (100 mm) and of 2.5 mM cetyltrimethylammonium bromide in a coil (22 cm) both flowing at the same rate and detection of the colored complex formed at 520 nm. Sample collection and sampling times were 10 and 18 s, respectively, and the sampling rate was 128 samples per h. To eliminate deviation of absorbance additivity the synergistic coefficient was established. Calibration graphs were linear from 0.05-0.35, 0.25-1 and 0.025-0.3 mg/l, respectively, for Mo, W and Ti. The method was applied to the analysis of synthetic sample and steel, with recoveries of 91.2-105.2%.
Molybdenum Titanium Tungsten Spectrophotometry Simultaneous analysis

"Determination Of Trace Silicon By A Flow Injection Differential Kinetic Chemiluminescence Method"
Fenxi Huaxue 1997 Volume 25, Issue 2 Pages 149-152
Jiang, H.L.;Yang, M.L.;Lu, J.R.

Abstract: Micro amounts of Si were determined by the cited method using a stopped-flow technique based on the chemiluminescence reaction of molybdosilicate (I) and molybdophosphate. A water sample was passed through a strongly acidic cation-exchange resin column. The eluate was diluted then mixed with a stream of 1 mM NH4 molybdophosphate in 80 mM H2SO4 then merged with a carrier stream of 1 mM NH4 molybdophosphate in 80 mM H2SO4. The resultant stream was passed at a flow rate of 2.5 ml/min through a 180 cm reaction coil. The stopped-flow times were 3 and 7 min and the chemiluminescence strength was measured with a home-made chemiluminescence analyzer.. The calibration graph was linear from 0.1-10 µg/ml Si; the detection limit was 20 ng/ml. The RSD was 2.8% (n=1). The method was used to determine Si in steel.
Silicon Chemiluminescence Ion exchange Kinetic Stopped-flow Resin

"Determination Of Trace Arsenic With L-cysteine As Prereductant Using Flow Injection-hydride Generation-atomic Absorption Spectrometry"
Fenxi Huaxue 1998 Volume 26, Issue 8 Pages 1037-1037
Xu, G.M.;Lu, X.H.;Yin, X.F.

Abstract: The title method is characterized by having low detection limit (0.05 µm/L), good precision (1.8% RSD), and fast operation (65 samples/h). The method has applied to the anal. of steel and sea water.
Arsenic Spectrophotometry Volatile generation

"Flow Injection Spectrophotometric Determination Of A Micro Amount Of Titanium Using O-nitrophenylfluorone And Hexadecyltrimethylammonium Bromide"
Fenxi Shiyanshi 1994 Volume 13, Issue 2 Pages 41-43
Shen, H.X.;Liu, Y.G.;Wang, X.J.;Liu, L.Z.

Abstract: Sample (80 µL) was injected into the flow injection analyzer. and carried in a stream of water at 4.2 ml/min to react with streams (1.3 ml/min) of 0.3 mM o-nitrophenylfluorone, 6 mM cetyltrimethylammonium bromide and 0.15 M H2SO4 in a reaction tube (100 cm long, 1 mm i.d.) before detection at 542 nm. The linearity range was 0.1 µg/g of Ti. Interferences due to Zr(VI), Sn(IV), Mo(VI), Nb and Ta could be overcome by masking and pre-treatment. The sampling rate was 100 runs/h. The method was used to determine Ti in alloy steels and pure Al.
Titanium Spectrophotometry Interferences

"Flow Injection Analysis Fluorescence Quenching Method For Determination Of Trace Phosphorus(V) And Silicon(IV)"
Fenxi Yiqi 1998 Volume 1998, Issue 2 Pages 50-52
Song, G.;Fang, G.

Abstract: A flow injection-fluorometric method was established for determining P(V) and Si(IV) based on the fluorescence quenching effect of rhodamine 6G due to the formation of ion-association complex in acid medium. Optimal conditions were determined The calibration curves were linear at 0-80 µg/L for P(V) and Si(IV). The method was used for the determination of P(V) and Si(IV) in samples of steel and Cu alloy with satisfactory results.
Phosphorus(V) Silicon(IV) Fluorescence Indirect Optimization Ion pair formation Quenching

"Thin-layer Electrolytic Cell Determination Of Copper By Flow Injection Method"
Gaodeng Xuexiao Huaxue Xuebao 1989 Volume 10, Issue 5 Pages 554-556
Zhu, Y.;Huang, S.;Long, Y.;Liu, H.;Zeng, L.

Abstract: The construction and characteristics are described of a thin-layer electrolytic cell with a vitreous carbon working electrode (1.21 cm2) for amperometric determination of Cu. Copper was determined in NH4Cl - aqueous NH3 medium at -0.30 V vs. SCE. The calibration graph (peak current vs. concentration.) was rectilinear from 1 µM to 10 mM Cu. The method was applied in the determination of Cu in aluminum alloys and steel.
Copper Electrode Amperometry Apparatus Detector

"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 Spectrophotometry Gradient technique Interferences Standard additions calibration

"Water-soluble Azo-reagents Of High Sensitivity And Their Applications"
Huaxue Shiji 1987 Volume 9, Issue 5 Pages 282-287
Nigita Hiroko

Abstract: A review is presented of the use of high-sensitivity reagents comprising pyridylazo- and azo-derivatives, in many of which sulfo-groups are introduced to increase solubility in water, for the determination of Ca, Mg, Cu, Fe, Zn, Ag, Ba or Co in drinking water, serum, glass, steel or nickel salts by flow injection AAS or spectrophotometric methods. (15 references).
Calcium Magnesium Copper Cobalt Iron Zinc Silver Barium Spectrophotometry Spectrophotometry Review

"Flow Injection Methods For Monitoring The Environment"
Indian J. Environ. Prot. 1989 Volume 9, Issue 6 Pages 412-419
Mahadevappa, D. S.

Abstract: Flow injection analysis methods are presented for determination of S2- in solution, residual Cl in solution, and aromatic sulfonylhaloamines (e.g., chloramine-T and chloramine-B) and Fe(III) based on previously reported spectrophotometric methods. Optimum conditions for all the determinations are described. The detection limits were 0.14 to 1.4 ppm and max. sampling rates were >200 samples h-1. Beer's law ranges and tolerance limits for diverse ions are reported. At pH 4.0, Fe (23.4 ppm) was determined in the presence of 120 ppm of Fe by using the reaction with sulfosalicylic acid. Chlorine in seawater samples and iron in steel were determined by the described methods.
Chloramine T Chloramine, B Sulfide Chlorine Iron Spectrophotometry Detection limit Optimization Interferences

"Characteristics Of Flow Injection Inductively Coupled Plasma Mass Spectrometry For Boron Analysis In Steels"
ISIJ Int. 1994 Volume 34, Issue 12 Pages 997-1001
A. G&oacute;mez COEDO and T. Dorado L&Oacute;PEZ

Abstract: A method for the determination of Boron in steels by FI-ICP-MS is described. It is shown that flow injection (FI) can alleviate problems arising from high amounts of dissolved solids in Inductively Coupled Plasma Mass Spectrometry (ICP-MS) due to the capability to operate with microliter amounts of sample with a rapid sample rate. Sample dissolution was carried out in a microwave oven using diluted aqua regia (HCl+HNO3, 3+1) and high pressure digestion vessels, which gave notable advantages over conventional dissolution techniques, such as lower costs, greater volatile retention, reduced contamination and faster dissolution rates. The operating parameters in flow injection ICP-MS, such as carrier flow rate, nebulizer flow rate, and injection volume were established. The detection limit obtained when direct sample nebulization was used, with a 0.05% (m/v) Fe concentration, was 1.2 mg g-1 B, compared to a detection limit of 0.2 mg g-1 when the FI system was used with samples containing a higher concentration of dissolved solids (0.5% (m/v) Fe). The influence of the internal standard on precision and accuracy was studied and Beryllium was selected as the internal standard. The RSDs obtained for four peak area determinations of 200 mL injection volumes of a solution of 100 ng mL-1 B in the presence of 0.5% (m/v) Fe were below 1.5%. The accuracy of the method proposed was verified by analyzing Reference Materials (EURONORM-CRM 097-1; BCS 456, 457 and 460; NBS 361, 363 and 365), using an external calibration system with calibration samples, prepared from a standard Boron solution, in the same acid medium as the test sample solutions.
Boron Mass spectrometry

"Simple, Rapid, And Precise Determination Of Manganese In Iron And Steel By Flow Injection Analysis"
J. Iron Steel Inst. Jpn. 1993 Volume 79, Issue 4 Pages 492-496
Takeshi YAMANE, Masae SAITO

Abstract: In order to improve the simplicity, rapidity, accuracy and precision in the chemical analysis of iron and steel, a flow-injection analysis (FIA) has been studied for manganese determination with photometric detection. The FIA system consists of a direct on-line coupling of coloring reaction and absorbance measurement in a continuous now mode ; manganese is oxidized by ammonium peroxodisulfate to MnO4- and the absorbances of the resultant solution are measured before and after the addition of sodium nitrite. The FIA manifold and the optimum reaction conditions were established for allowing this simultaneous measurements of analytical and blank signals by single sample injection with single detector. The analytical results by the proposed method for four Japanese standards of steel (The Iron and Steel Institute of Japan) agreed well with the certified values for manganese and showed high precision of relative standard deviations of 0.25-0.50% which are much smaller than those usually observed in manually operated spectrophotometric methods. An injection rate of 12 sample solutions/h can be achieved. The most appealing feature of the proposed method is that the analysis is achieved in a continuous and nearly closed system without complicated manual operations, which can afford simpler and rapid as well I as accurate and precise determination of manganese.

"Analyses Of Some Practical Samples By FI-MPT-AES"
Jilin Daxue Ziran Kexue Xuebao 1998 Volume 36, Issue 1 Pages 91-93
Zou Mingqiang; Wang Daning; Zhao Xiaojun; Liang Feng; Yuan Mao; Zhang Hanqi; Jin Qinhan

Abstract: The analyzes of some practical samples by FI-MPT-AES (flow injection-microwave plasma torch-at. emission spectrometry) were carried out for samples including Al alloy, alloy steel, catalyst, and biological samples. The method established is acceptable for analyzing the practical samples.

"Flame Atomic Absorption Determination Of Trace Cobalt In Steel Samples Using A Flow Injection Online Separation System"
Lab. Rob. Autom. 1998 Volume 10, Issue 5 Pages 299-305
M. C. Yebra-Biurrun

Abstract: A flow injection online system was developed for the trace determination of Co by flame atomic absorption spectrometry (FAAS) with separation and pre-concentration on a minicolumn packed with a poly(aminophosphonic acid) chelating resin (PAPhA). This resin allows the selective separation of Co at pH 2 because Co(II) and Fe(III) are the only metal ions retained quant. at this pH level, and Co(II) presents a greater selectivity coefficient than Fe(III); therefore, Co(II) is preferentially complexed over Fe(III) on the active groups of the chelating resin. Elution was performed by using a small volume of 0.2 M HNO3. At a consumption of 7 mL sample volume, the procedure resulted in an enhancement factor of 83 and yielded a detection limit of 0.15 µg/L (3s) at a sampling frequency of 32 h-1. The precision (coefficient of variation, n = 11) was in the range 0.5-1.0% at the 1-15 µg/L level. The procedure was applied to the determination of Co in steel samples with high tolerance to interferences, and results obtained for a standard reference material were in good agreement with the certified value.
Cobalt Spectrophotometry Preconcentration Column Complexation Interferences Resin Reference material

"Flow-injection Analysis Determination Of Silicon In Steel"
Lihua Jianyan, Huaxue Fence 1989 Volume 25, Issue 1 Pages 43-49
Li, M.;Zhang, H.

Abstract: Standard Si solution were mixed with 50% HCl and HNO3 and diluted to volume with water. Ammonium molybdate, oxalic acid and SnCl2 were fed into reaction columns in series and the acidified sample solution were injected through a rotating valve into this flow-injection analysis system for measurement of the absorbance at 740 nm. The calibration graph was rectilinear up to 30 g mL-1 of Si. The detection limit was 0.25 g mL-1. For steel samples containing 0.11 to 1.33% of Si, the coefficient of variation (n = 11) varied between 2.5 and 0.7%. Ninety samples per hour can be analyzed by this method.
Silicon Spectrophotometry

"FIA Determination Of Traces Of Molybdenum By The Ternary Reaction System Molybdenum(VI)-pyrocatechol Violet-crystal Violet"
Lihua Jianyan, Huaxue Fence 1993 Volume 29, Issue 6 Pages 355-356
Song, X.P.

Abstract: Sample (100 µL) was injected at 7 ml/min into the flow injection analyzer. before passing through a cation-exchange column (5 cm x 1.5 mm i.d.) and the eluate was carried by a stream of 2 mL of 0.04% pyrocatechol violet, 10 mL of 1% poly(vinyl alcohol)-124 and 10 mL of 10% K H phthalate buffer of pH 3.5 (A) at 7 ml/min to a reaction tube (200 cm long) to react with a reagent stream containing 8 mL of 0.04% C. I. Basic Violet 3 (crystal violet) and 10 mL of 10% buffer A at 7 ml/min. The ternary complex produced was detected at 645 nm. Beer's law was obeyed for 20-500 µg/l of Mo. The detection limit was 20 µg/l. Although Fe(III), Pb(II) and Zn(II) interfered, they could be removed by ion-exchange separation. The method was used in the assay of steels, with recovery of 95% and RSD of 5-3%.
Molybdenum Ion exchange Spectrophotometry Interferences Complexation

"Determination Of Traces Of Cobalt And Nickel In Steels By Flow Injection Online Extraction - Flame Atomic Absorption Spectrometry"
Lihua Jianyan, Huaxue Fence 1997 Volume 33, Issue 2 Pages 59-60
Gong Yu, Zhou Junming, Tang Zhiyong, Zhang Suicheng and Jin Zoxiang

Abstract: Sample (0.1 g) was heated gently to decompose in concentrated HCl and 2 mL HNO3 (1:1) then concentrated to 2 mL and cooled. The residue was treated with 5 mL triethanolamine and neutralized with HCl (1:1) and ammonia water. Having diluted with water to 25 mL (pH 7), a portion of the solution was injected into the flow injection online extraction setup (diagram illustrated) into a carrier stream of water (10 ml/min). The flow passed through a segregator into an extraction coil (3 m x 1 mm i.d.) with 2% ammonium pyrrolidinedithiocarbamate in IBMK as extractant (0.5 ml/min) for extraction for 1 min, with an organic-phase sampling time of 1 min. Determination of Co and Ni was by flame AAS. Detection limits for Co and Ni were 0.01 and 0.02 µg/ml, respectively. The method was used in the analysis of metallurgical-standard steels, with RSD of 3.9-6%.
Cobalt Nickel Spectrophotometry Sample preparation Detection limit Solvent extraction MIBK Phase separator Reference material

"Development Of A Rapid Analyser For Aluminum Control In Steel"
Steel Res. 1990 Volume 61, Issue 5 Pages 201-203
Coutinho, C.A.;Arruda, E.C.;Mundim, M.J.;Pachecode Araujo, W.

Abstract: A review is presented, with 5 references, with discussion on the various methods used for the determination of soluble Al. A recently developed and patented instrument, using a special electrolysis cell for rapid dissolution of the solid steel samples, and a computer-controlled flow injection spectrophotometric analyzer., are described. Typical analysis time for duplicate determination is 150 s. Recovery was quantitative.
Aluminum Sample preparation Review Computer

"Determination Of Phosphorus And Silicon In Carbon Steel And Low-alloy Steel By Flow Injection Analysis"
Yejin Fenxi 1989 Volume 9, Issue 3 Pages 30-33
Shen, Jihua; Miao, Fengqin

Abstract: The determination is based on the molybdenum blue method. The sample solution is treated with NH4F to eliminate the interference of ferric molybdate. The sample solution is used as the carrier flow and mixed with ammonium molybdate solution to form the heteropolyacid. After a fixed amount of reducing agent is injected, molybdenum blue forms for determination of phosphorus and silicon. The method is simple and rapid in analysis of carbon and alloy steel.
Phosphorus Silicon Spectrophotometry Interferences

"Flow Injection Spectrophotometric Determination Of Microamounts Of Tin"
Yejin Fenxi 1990 Volume 10, Issue 1 Pages 58-60
Yang, J.;Liu, G.;Jiang, Y.

Abstract: Tin was determined in steels by flow injection spectrophotometry by measuring the absorbance at 506 nm of the ternary complex formed with phenylfluorine and OP at 70°C in the presence of citric acid and ascorbic acid as masking agents. Beer's law was obeyed up to 8 µg mL-1. The coefficient of variation were 1.8 to 11%.
Tin Spectrophotometry Complexation Interferences Heated reaction

"Determination Of Molybdenum In Steels By Flow Injection Spectrophotometry With Thiocyanate"
Yejin Fenxi 1991 Volume 11, Issue 6 Pages 26-28
Jiang Chung-Shi

Abstract: Steel was digested in aqua regia and Fe(III) was reduced with SnCl2 before the determination of Mo by flow injection spectrophotometry with KSCN as color reagent.
Molybdenum Sample preparation Spectrophotometry

"Flow Injection Spectrophotometric Determination Of Microamount Of Molybdenum By Using Salicylfluorone"
Yejin Fenxi 1993 Volume 13, Issue 5 Pages 1-3
Shen, Hanxi; Liu, Yuguo; Wang, Xinjing; Liu, Liuzhan

Abstract: A flow injection system using a 721 spectrophotometer was developed for the determination of microamounts of molybdenum. Salicylfluorone and cetyltrimethylammonium bromide were used as the reagents. The optimal experimental conditions of determination were studied. The analysis rate was 150 sample/h and the linear determination range was 0-0.5 ppm. The method was used to determine microamounts of molybdenum in alloy steels with satisfactory results.
Molybdenum Spectrophotometry Optimization

"Determination Of Molybdenum In Low-alloy Steel By Flow Injection Spectrophotometry"
Yejin Fenxi 1993 Volume 13, Issue 5 Pages 51-53
Liu, Yirong; Miao, Fengqin; Wu, Saiying; Ge, Shaopeng (SFS)

Abstract: A flow-injection system was designed for determination of molybdenum in low-alloy steel using orthophosphate-KSCN-molybdenum system. In the 1st reactor Mo(VI) reacted with thiocyanate to form Mo(SCN)6, which was reduced to Mo(SCN)5 in the second reactor. Mo(SCN)5 has an absorption maximum at 475 nm with a molar absorptivity of 1.67 x 10^4 and Beer's law is obeyed for 0-10 mg/mL. Molybdenum was determined in low-alloy steel samples with relative standard deviation <1.5%.
Molybdenum Spectrophotometry

"Flow Injection Analysis. Spectrophotometric Determination Of Nickel"
J. Anal. Chem. 1986 Volume 41, Issue 7 Pages 1224-1227
Shpigun, L.K.;Kolotyrkina, I.Y.;Zolotov, Y.A.

Abstract: The method involves oxidation of Ni(II) to Ni(II)I in a reagent stream (1.2 mL min-1) of 25 mM iodine in 0.1 M HCl containing 30% of ethanol [a reaction coil (1.2 m x 0.7 mm) is used] and subsequent complex formation of Ni(II)I with dimethylglyoxime (I) in another reagent stream (2.0 mL min-1) of 25 mM I in 0.2 M NaOH containing 50% of ethanol [another coil (1.2 m x 0.7 mm) is used]. The analysis is performed on a Tecator FIAStar 5020-003 analyzer. equipped with a spectrophotometric detector having an 18 µL flow-through cell (λmax = 475 nm); 200 µL samples are injected at 60 to 90 h-1. The coefficient of variation is 1% (n = 3) when determining ~0.02 to 4.2% of Ni in alloy steels containing W or Cr but no Cu; Fe must be masked with tartrate during sample preparation.
Nickel(II) Spectrophotometry Interferences Redox Tecator

"Determination Of Phosphorus Content In Steels Using Flow Injection Into An Argon-water Carrier For Inductively Coupled Plasma-mass Spectrometry"
ISIJ Int. 1997 Volume 37, Issue 9 Pages 878-884

Abstract: This paper describes a methodology for the determination of phosphorus in steels using argon-water carrier, in flow injection with Inductively Coupled Plasma Mass Spectrometry. 31P is a monoisotopic element and its determination, at very low levels, is very difficult due to contamination problems and interference inherent in the plasma and solvents. These unduly raise the background being necessary a sample pretreatment step to achieve the required contents. To dissolve the samples in this study, a microwave digestion system was applied to minimize the sample preparation time, the quantities of reagents and the risk of contamination. A mercury cathode electrolysis was used for performing a rapid matrix removal/analyte enrichment. The use of an argon-water stream as carrier yielded an enhancement in sensitivity and the detection limit was improved by a factor of approximately 2.5 when compared with that experienced using flow injection into an all-water carrier. Optimization of the operating conditions for the argon-water flow injection and for Inductively Coupled Plasma Mass Spectrometer, were selected with respect to the peak height sensitivity and were found to be dependent on the nebulizer gas flow-rate, the radio frequency power, the sample injection volume and the carrier flow-rate. The detection limit based on a sample rate of 0.02 g ml-1 was 0.4 mg g-1 and the relative standard deviations at 100 and 10 mg g-1 P solution were 2.0 and 15 % respectively. Data are presented for three Standard Reference Materials: JSS 003-2, (from Japanese Iron and Steel Certified Reference Materials); and ECRMs 285-1 and 278-1 (from Bureau of Analysed Samples LTD).
Phosphorus Mass spectrometry Optimization Reference material Interferences