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

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Environmental

Classification: Environmental -> sediment

Citations 45

"Atomic Fluorescence Determination Of Inorganic Arsenic In Soils After Microwave-assisted Distillation"
Anal. Chim. Acta 2000 Volume 407, Issue 1-2 Pages 155-163
Cristina Maria Barra, M. Luisa Cervera, Miguel de la Guardia and Ricardo Erthal Santelli

Abstract: An inexpensive microwave-assisted distillation procedure has been developed for quantitative determination of inorganic arsenic in soils by atomic fluorescence spectrometry (AFS). After reduction of As(V) to its trivalent state with potassium iodide, inorganic arsenic was distilled as AsCl3 that was finally determined by atomic fluorescence after hydride generation with NaBH4 in HCl medium. The different parameters that control the distillation: concentration and volume of HCl, time of distillation, sample weight, and oven load, win studied. The methodology developed has a detection limit of 0.015 µg L-1 which corresponds to a concentration of 0.006 µg of As per gram of soil, and a relative standard deviation of 3% for nine independent analyzes of the same soil sample containing 8.7 µg g-1 As. The recovery percentage of As(III) and As(V) were 103±4 and 106±4%, respectively, Total arsenic was determined after microwave-assisted digestion, under pressure, with HCl : HNO3 (3 : 1)/H2O2 in hermetically sealed Teflon reactors. By introducing an additional microwave-assisted digestion step after distillation of inorganic arsenic, the organic fraction of arsenic in soils and sediments was established.
Arsenic(3+) Arsenic(5+) Arsenic, inorganic Fluorescence Sample preparation Volatile generation Speciation

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

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

"Spectrophotometric Determination Of Phosphate And Silicate By Sequential Injection Using Molybdenum Blue Chemistry"
Anal. Chim. Acta 2000 Volume 417, Issue 2 Pages 191-200
Cristiane X. Galhardo and Jorge C. Masini

Abstract: This paper presents a spectrophotometric sequential injection (SI) determination of phosphate and silicate in environmental samples and cell cultivation medium using the molybdenum blue reaction. The interference of silicate in the determination of phosphate was eliminated by using a reagent composed of 5 mmol L-1 ammonium molybdate in 0.2 mol L-1 nitric acid, containing 0.25% (w/v) oxalic acid to avoid the formation of molybdosilicic acid. The interference of phosphate in the determination of silicate was avoided adding a 10% (w/v) oxalic acid solution to the reaction zone where the molybdophosphoric and molybdosilicic acids were previously formed, in order to destroy the molybdophosphoric acid. To perform this task in the single Line SI system, obtaining a total sample and reagent zones penetration, it was used as a combination of sandwiching the sample zone between reagent zones and flow reversal through an auxiliary reaction coil. The method has a phosphate sampling frequency of 75 hr-1, with a linear dynamic range between 0.2 and 7 mg L-1 and a detection limit of 0.1 mg L-1 PO43 = P. For silicate, the sampling frequency is 40 h-1 with a linear dynamic range between 5 and 50 mg L-1 and a Limit of detection of 1 mg L-1 SiO32 = Si.
Phosphate Silicate Spectrophotometry Sequential injection Interferences Flow reversal

"Flow Injection On-line Sorption Preconcentration And Separation Coupled With Atomic (mass) Spectrometry For Trace Element (speciation) Analysis"
Acta Chim. Sin. 2001 Volume 59, Issue 7 Pages 987-993
YAN Xiu-Ping

Abstract: Flow injection (FI) on - line sorption separation and pre-concentration coupled with atomic (mass) spectrometry using knotted reactors (KRs) for trace element (speciation) analysis is discussed. Compared with FI on - line C-18 column pre-concentration systems, the KR sorption system permits use of higher sample loading rates to achieve higher concentration efficiencies due to low hydrodynamic impedance in the KR. Moreover, the KR allows the analysis to be conducted at low cost, owing to the long lifetime of the KR and its ease of construction with no need for packing materials, offering a good alternative to conventional C-18 column pre-concentration systems.
Lead Copper Mass spectrometry Preconcentration Knotted reactor C18 Speciation

"Flow Potentiometric Stripping Analysis For Mercury(II) In Urine, Sediment And Acid Digest Of Biological Material"
Anal. Chim. Acta 1982 Volume 141, Issue 1 Pages 157-162
Daniel Jagner and Kerstin Årén

Abstract: In flow potentiometric stripping analysis for mercury in urine, the samples are acidified with concentrated nitric acid and heated to boiling for 10 min. After cooling, the samples are buffered by the addition of concentrated ammonia and then pre-electrolysed at a gold working electrode for 90 s at -0.25 V vs. SCE at a flow rate of 1.75 mL min-1. The stripping solution is 1 M sodium bromide solution acidified with 0.1 M hydrochloric acid and containing chromium(VI). The detection limit at one σ level is 0.05 µM. Orchard leaves, sediment and fish muscles are digested in nitric acid at 140°C for 30 min prior to buffering with ammonia and potentiometric stripping analysis for 200 s at -0.20 V vs. SCE at a flow rate of 1.75 mL min-1.
Mercury(II) Clinical analysis Potentiometric stripping analysis Sample preparation

"Improved Chemiluminescence Determination Of Traces Of Cobalt(II) By Continuous-flow And Flow Injection Methods"
Anal. Chim. Acta 1983 Volume 155, Issue 1 Pages 259-262
Masaaki Yamada, Takayuki Komatsu, Shinjiro Nakahara and Shigetaka Suzuki

Abstract: Limits of detection and sampling rates in the methods of Nakahara et al. (cf. Anal. Abstr., 1983, 44, 3B147) have been improved by factors of 70 and 6, respectively, by increasing the reaction temperature to 60°C and modifying the compositions of the reagent solution In the flow injection method, the sample (10 µL) is injected into a carrier stream of dilute acid (pH 2.8), which is subsequently added to a pre-mixed reagent stream comprising 0.2 M gallic acid - 0.3 M H2O2 and 0.09 M NaOH in 3% methanol. The resulting mixture is passed through a reaction coil (1.6 m) at 60°C before measurement of the luminescence intensity (loc. cit.). Calibration graphs are rectilinear over three decades of concentration, and the limit of detection is 0.6 pg for a 10 µL sample (0.6 ng L-1 for the continuous-flow procedure); for 60 pg of Co the coefficient of variation is 1.5%. Silver enhances the signal, and CN-, Cr2O72-, CO32- and EDTA suppress the luminescence intensity, but Fe(III), Mn(II), Cr(III), Ni(II), Pb(II), Cu(II) and MnO4- do not interfere. Results obtained on standard reference materials (pond sediment and pepperbush) agree with certified values; the method has also been applied to tap-water. The sampling rate is 120 h-1.
Cobalt(II) Chemiluminescence Interferences Heated reaction Reference material

"Determination Of Nickel And Cobalt In Natural Waters And Biological Material By Reductive Chronopotentiometric Stripping Analysis In A Flow System Without Sample Deoxygenation"
Anal. Chim. Acta 1985 Volume 175, Issue 1 Pages 79-88
H. Eskilsson and C. Haraldsson, D. Jagner

Abstract: Samples (100 ml) of natural waters, or portions (0.5 to 5 ml) of acid digests of seawater sediments or bovine liver, were mixed with 3 M NH3 - HCl buffer (pH 9.2) and 0.1 M dimethylglyoxime(I) solution in ethanol; Co(III) species formed during acid digestion were reduced with NaBH4. Electroanalysis was performed in a thin-layer flow cell with a vitreous-carbon working electrode. The microprocessor-controlled operational sequence included(I) plating of a mercury film on to the carbon electrode;(II) potentiostatic adsorption (at -0.5 V vs. the SCE) of the Ni(II) - and Co(II) - I complexes on to the mercury film; (iii) constant-current reduction of the metal ions in a 5 M CaCl2 medium and simultaneous recording of the working-electrode potential vs. time; (iv) chemical removal of the mercury film; and (v) cleaning of the vitreous-carbon surface. To determine Co in presence of a large excess of Ni, an adsorption potential of -0.75 V vs. the SCE was used. Detection limits (after 70 s of adsorption) were 8.6 ng L-1 for Ni(II) and 10.5 ng L-1 for Co(II).
Nickel Cobalt Potentiometric stripping analysis Electrode Sample preparation Interferences

"Flow Injection Analysis For Traces Of Zinc With Immobilized Carbonic Anhydrase"
Anal. Chim. Acta 1985 Volume 178, Issue 2 Pages 209-215
Kunio Kashiwabara, Toshiyuki Hobo, Eigo Kobayashi and Shigetaka Suzuki

Abstract: Bovine carbonate dehydratase was immobilized on CNBr-activated Sepharose 4B and packed in a small glass column. The metal ions were removed from the enzymes easily by passing 0.01 M pyridine-2,6-dicarboxylic acid through the column at 1.0 mL min-1. The activity increase after passing a Zn sample solution through the column was measured by injecting 0.1 M 4-nitrophenyl acetate in dimethyl sulfoxide into the Tris buffer stream and measuring at 400 nm the 4-nitrophenol formed. The increase in peak area was proportional to the amount of Zn in the sample. A rectilinear calibration graph was obtained for 10 to 400 ng of Zn. The coefficient of variation for 0.13 µg of Zn was 4.9%. The method was successfully applied to the determination of Zn in tea, sediment and spring water. The immobilized enzyme can be used repeatedly and Zn can be concentrated on the column, permitting very low concentration. to be determined.
Zinc Spectrophotometry Immobilized enzyme Preconcentration

"Determination Of Arsenic And Selenium In Environmental Samples By Flow Injection Hydride-generation Atomic Absorption Spectrometry"
Anal. Chim. Acta 1992 Volume 270, Issue 1 Pages 231-238
Chris C. Y. Chan* and Ram S. Sadana

Abstract: Environmental samples such as soil, vegetation, water, sediments and industrial wastes were digested (except for water) by heating at 200°C with HNO3 - H2SO4 - HClO4 (6:3:1). The cooled digest or water was treated with concentrated HCl to reduce Se6+ to Se4+; for As analysis the solution was treated with 10% KI - 1% ascorbic acid (10:1) to reduce As5+ to As3+. The analytes were converted to the hydrides with 1% NaBH4 in an automated hydride-generation system. A stream of Ar (3 mL min-1) carried the evolved hydride via a gas - liquid separator and an impinger to a heated quartz tube atomizer for analysis by AAS. The effects of the experimental variables are discussed. Interference by Cu and Ni on the determination of Se was masked with 1,10-phenanthroline. The detection limits for both As and Se were 0.3 ng mL-1. The coefficient of variation was 2.6% for As in a sediment (n = 10) and 2% in water (n = 5); similar precision was obtained for Se. The results for the standard reference materials agreed closely with their certified values. Flow injection analysis is applied to sample introduction in conjunction with automated hydride generation and AAS for the determination of As and Se in environmental samples such as soil, vegetation, waters, sediments, and industrial wastes. A large sample loop was used to provide high sensitivities with an absorbance of 0.4 for 10 ng mL-1 for both As and Se. The samples, except waters, are digested with a mixture of nitric, sulfuric, and perchloric acids. Se6+ in the digested solutions is pre-reduced to Se4+ by exothermic reaction in 6-8 M HCl solution, and As5+ to As3+ by reacting with KI. The analyte is then converted to hydride by NaBH4 in an automated hydride generation system. The evolved hydride is carried through to a heated quartz tube by a stream of argon, and the atomic absorption of the analyte is measured. 1,10-Phenanthroline is used as masking agent to control interferences from Cu and Ni on Se. The detection limits for both As and Se are 0.3 ng mL-1, equivalent to 75 ng g-1 in solid sample. Precision is 2.6% RSD Results for standard reference materials agree closely with the certified values.
Arsenic Selenium Spectrophotometry Reference material Interferences Volatile generation Volatile generation

"Comparison Of Plumbane And Tetraethyllead For The Determination Of Lead By Inductively Coupled Plasma Atomic-emission Spectrometry"
Anal. Chim. Acta 1995 Volume 309, Issue 1-3 Pages 369-378
M. C. Valdés-Hevia y Temprano, M. R. Fernández de la Campa and A. Sanz-Medel*

Abstract: Sediments and lichen (200 mg) were microwave digested in 1.5 mL concentrated HNO3, 0.5 mL 80% HClO4 and 0.5 mL concentrated HF (details given). After cooling, the excess HF was reacted with 3.5 mL 6% H3BO3, the mixture re-digested and the contents made to 100 mL with water. Citrus leaves and lyophilized vegetables (0.5 g) were digested in 5 mL 65% HNO3 and 2 mL H2O2 and the contents made to 25 mL with water. The solutions were mixed to contain 0.3% or 0.7% K2Cr2O7 for PbH4 (I) or tetraethyllead (II) analysis and merged at 1 ml/min with carrier streams (1 ml/min) of 360 mM or 600 mM lactic acid for I and II, respectively, and 5% NaBH4 in 0.1% NaOH for I or 1% sodium tetraethylboron in 1% NaOH for II. The mixed solutions were aspirated at 2.4-3 ml/min into a detuned grid-nebulizer for ICP-AES and Pb determined at 0.7 kW and 20.353 nm. Calibration graphs were linear up to 0.5 mg/ml of I and 1.5 mg/ml of Pb for II with detection limits of 2 ng/ml and 1 ng/ml of Pb, respectively. At 50 ng/ml of Pb the RSD (n = 10) were 1.3% for I and 1.2% for II. The selectivity of the two methods in the presence of chloride, nitrate and a range of cations was confirmed. The analysis of Pb via II was preferred as only Ni and Sb interfered.
Lead Sample preparation Spectrophotometry Interferences Volatile generation Optimization Volatile generation

"Spectrofluorimetric Method For The Determination Of The Total Mercury Content In Sediment And Soil"
Anal. Chim. Acta 1997 Volume 355, Issue 2-3 Pages 151-156
I. Vedrina-Dragojevic*, D. Dragojevi and S. Cadez

Abstract: A spectrofluorimetric method based on fluorescence quenching of rhodamine B with Hg(II) in the presence of potassium iodide for the determination of the total mercury in sediment and soil is described. All forms of mercury are pre-oxidized to ionic mercury by acidic potassium permanganate and finally complete oxidation is achieved by potassium persulphate and heating. Hg(II) was reduced by tin(II) chloride and vapor driven by an air stream into an absorption solution containing potassium permanganate and sulphuric acid, using a closed, recirculating air stream. Fluorescence quenching of rhodamine B is measured in the absorption solution at an excitation wavelength of 485 nm and an emission wavelength of 586 nm. The proposed method gives good recovery of added mercury (mean 98.0%), good repeatability (RSD 1.64%) and reproducibility (RSD 2.17%) and low detection limit (0.7 ng Hg mL-1 of measuring solution). No significant concentration of total mercury present in sediment and soil samples from the largest deposits of oil in Croatia have been found.
Mercury Methylmercury ion Fluorescence Sample preparation Extraction

"Determination Of Arsenic By Inductively Coupled Plasma Atomic-emission Spectrometry Enhanced By Hydride Generation From Organized Media"
Talanta 1992 Volume 39, Issue 11 Pages 1517-1523
B. Aizpun Fernandez, C. Valdes-Hevia y Temprano, M. R. Fernandez de la Campa and A. Sanz-Medel*P. Neil,

Abstract: The cited method is based on continuous-flow generation of arsine with NaBH4 from a didodecyldimethylammonium bromide (I) vesicular medium. The analytical performance of this technique was superior to the generation of the hydride from aqueous media. Optimization of experimental parameters is described. The detection limit (0.6 ppb) was improved by a factor of 2 and there was a greater tolerance to interferences for arsine generated from I vesicles; precision of the As determination was also improved. The method was validated for low As level determinations in two Certified Reference Materials (sediments). The potential of organized media to improve hydride generation is also discussed.
Arsenic Mass spectrometry Optimization Preconcentration Volatile generation Interferences Reference material Volatile generation

"Elimination Of Hydrofluoric Acid Interference In The Determination Of Antimony By The Hydride Generation Technique"
Talanta 1998 Volume 45, Issue 5 Pages 801-806
A. D'Ulivo*, L. Lampugnani, D. Faraci, D. L. Tsalev and R. Zamboni

Abstract: For the determination of Sb by hydride generation techniques a pretreatment procedure was developed for the reduction of Sb(V) to Sb(III) to remove the effect of HF which strongly interferes with the reduction of pentavalent Sb to the trivalent state. It is based on the combined action of L-cysteine and boric acid at 80°C. The pretreatment is effective in both nitric and HCl media. Quant. recoveries were obtained in <60 min. Under these conditions Sb is reduced to the trivalent state in acid media containing both nitric and HCl. The method was applied to the determination of total Sb in certified reference materials of sediments after pressurized microwave digestion with HNO3-HCl-HF. Good agreement was obtained by using both anal. techniques: continuous-flow hydride generation atomic fluorescence spectrometry and flow injection electrothermal atomic absorption spectrometry with in-situ trapping of stibine in a graphite atomizer.
Antimony(3+) Antimony(5+) Spectrophotometry Fluorescence Sample preparation Interferences Volatile generation Method comparison Reference material

"Comparison Of Instrumental Methods For The Determination Of Total Selenium In Environmental Samples"
Analyst 1993 Volume 118, Issue 10 Pages 1303-1308
Philip M. Haygarth, A. Philip Rowland, Stefan St&uuml;rup and Kevin C. Jones

Abstract: Fluorimetry, radiochemical NAA, hydride-generation AAS, ICP-AES and ICP-MS were objectively compared for the determination of total Se in environmental materials with respect to their detection limits, calibration range, linearity, sensitivity, reproducibility, analysis time and interferences. A sediment matrix was used as an example. A novel flow injection system was constructed and adapted for AAS to improve the efficiency of hydride-generation systems. Fluorimetry and hydride-generation AAS and ICP-AES continue to be useful for routine laboratory determinations of Se in environmental samples although the fluorimetric method is becoming dated. For samples of low Se concentration, hydride-generation ICP-MS and radiochemical NAA methods are superior.
Selenium, total Fluorescence Spectrophotometry Spectrophotometry Mass spectrometry Neutron activation analysis Method comparison Volatile generation Interferences Volatile generation

"Simultaneous Spectrofluorimetric Determination Of Selenium(IV) And (VI) By Flow Injection Analysis"
Analyst 1997 Volume 122, Issue 3 Pages 221-226
M. J. Ahmed, C. D. Stalikas, P. G. Veltsistas, S. M. Tzouwara-Karayanni and M. I. Karayannis

Abstract: A sample (100 µL) was injected into a carrier stream of 2 M H2SO4 at a flow rate of 0.1 ml/min and mixed with a reagent stream of 0.2 mM 2-(α-pyridyl)thioquinaldinamide in propan-2-ol at a flow rate of 0.3 ml/min. The fluorescence intensity due to Se(IV) was measured at 500 nm (excitation at 350 nm). A second portion (100 µL) was then injected into the carrier stream and passed through a coil (40 cm x 0.8 mm i.d.) where it was irradiated at 254 nm. The irradiated sample stream was then mixed with the reagent stream and the fluorescence intensity due to total Se was measured. Se(VI) was determined from the difference in the two fluorescence intensity values. The calibration graphs were linear from 0.01-2.2 and 0.1-2.4 µg/ml Se(IV) and Se(VI), respectively; corresponding detection limits were 1 and 10 ng/ml. RSD were 0.1-2% (n=5). The throughput was 25 samples/h. The method was applied to the analysis of alloys, hair, tap and lake water, sediments, soil, tea, flour and eggs. A simple, sensitive, highly selective, automatic spectrofluorimetric method for the simultaneous determination of selenium (IV) and (VI) as selenite-selenate by flow injection analysis (FIA) has been developed. The method is based on the selective oxidation of the non-fluorescent reagent 2-(α-pyridyl)thioquinaldinamide (PTQA) in acidic solution (1.5-3.0 M H2SO4) by Se(IV) to give an intensely fluorescent oxidation product (lambda ex =350 nm; lambda em = 500 nm). Selenium (VI) is reduced online to Se(IV), in a reduction coil installed in a photo- reactor, which is then treated with PTQA and the fluorescene due to the sum of Se(IV) and Se(VI) is measured; Se(Vi) is determined from the difference in fluorescence values. Various analytical parameters, such as effect of acidity, flow rate, sample size, dispersion coefficient, temperature, reagent concentration and interfering species were studied. The photo-reduction conditions were optimized, with an FIA procedure, for Se(VI) on the basis of its reduction efficiency. The calibration graphs were rectilinear for 0.1-2.4 µg mL-1 of Se(VI) and 10 ng mL-1 - 2.2 µg mL-1 of Se(IV), respectively. The method was applied to the determination of Se in several Standard Reference Materials (alloy, sediments and tea), as well as in some environmental waters (tap and surface water), food samples (flour and egg), a biological sample (human hair), soil sample and in synthetic mixtures. Up to 25 samples per hour can be analyzed with an RSD approximately 0.1-2%.
Selenium(IV) Selenium(VI) Fluorescence Speciation Photochemistry Selectivity Reference material Interferences

"Speciation Analysis Of Chromium(III) And Chromium(VI) Using Flow Injection Analysis With Fluorometric Detection"
Analyst 1998 Volume 123, Issue 5 Pages 1005-1009
Evangelos K. Paleologos, Spyros I. Lafis, Stella M. Tzouwara-Karayanni and Miltiades I. Karayannis

Abstract: A relatively simple, sensitive, selective, automatic fluorometric method for the simultaneous determination of Cr(III) and Cr(VI) by flow injection analysis (FIA) was developed. The method is based on the selective oxidation of the nonfluorescing reagent 2-(α-pyridyl)thioquinaldinamide (PTQA), which with Cr(VI) yields an intensely fluorescent product (λex = 360 nm; λem = 500 nm). Cr(III) is oxidized online to Cr(VI) with sodium metaperiodate and the Cr(VI) is subsequently treated with PTQA. Fluorescence due to the sum of Cr(III) and Cr(VI) is measured and Cr(III) is determined from the difference in fluorescence values. The effects of various anal. parameters, such as acidity, flow rate, sample volume, temperature, reagent concentration and interfering species, were studied. Kinetic studies using both the stopped-flow technique and the FIA procedure were used to study and optimize the oxidation conditions for Cr(III) from its oxidation efficiency. The calibration graphs were rectilinear in the ranges 0.1-10 µg mL-1 for Cr(VI) and 0.1-1.0 µg mL-1 for Cr(III). The method was successfully verified by performing recovery experiments of Cr in several standard reference materials (peach leaves, sediments and tea), and it was applied to the speciation analysis of Cr(III)-Cr(VI) in environmental waters (mineral, tap and distilled water), a food sample (tomato juice) and synthetic mixtures. Up to 30 samples per h can be analyzed with a relative standard deviation of ~0.1-2%.
Chromium(III) Chromium(VI) Fluorescence Speciation Stopped-flow Kinetic Reference material Indirect Interferences Optimization

"Evaluation Of The Determination Of Mercury At The Trace And Ultra-trace Levels In The Presence Of High Concentrations Of NaCl By Flow Injection-cold Vapor Atomic Absorption Spectrometry Using SnCl2 And NaBH4 As Reductants"
Analyst 1998 Volume 123, Issue 6 Pages 1219-1222
O. Haase, M. Klare, K. Krengel-Rothensee and J. A. C. Broekaert

Abstract: The influence of different concentrations of NaCl (0-20%(m/v)) on the analytical figures of merit for the determination of Hg by flow injection-CVAAS was studied. The determination was performed with and without pre-concentration by Au amalgamation and by employing different reducing agents, NaBH4 and SnCl2. When using the reductant SnCl2, stable operation both with and without pre-concentration was obtained, resulting in RSDs <5% (n ≥ 30), even in the presence of high concentrations of NaCl. Without pre-concentration the sensitivity was a function of the concentration. of NaCl (between 0.033 and 0.013 mL ng-1). With pre-concentration the sensitivity could be improved by a factor of 2.5 (i.e., from 0.084 to 0.037 mL ng-1, depending on the concentration. of NaCl). With the reducing agent NaBH4, sufficient stability for routine anal. was observed only without pre-concentration (relative standard deviation ≤2%, n = 45) and a sensitivity of 0.022 mL ng-1 was obtained for matrix-free solutions In the presence of high concentrations. of NaCl the sensitivity increased up to 0.030 mL-1 ng, but owing to the unsystematically unstable blank values it was not a monotonic function of the concentration of NaCl. The use of pre-concentration in the case of NaBH4 was hampered by the Au trap being covered with gaseous reaction products or entrained droplets as a result of the generation of foam in the gas-liquid separator. This could be improved using two gas-washing bottles (NaOH, H2O). With the different methods, for which the detection limits finally were 15-230 pg mL-1 (without) and 2 and 11 pg mL-1 (with pre-concentration), Hg was determined in five standard reference samples of soil and sedimented sludge at the ng g-1 to µg g-1 level subsequent to their dissolution with aqua regia.
Mercury Spectrophotometry Method comparison Optimization Reference material Amalgamation Interferences Ionic strength Dissolved solids

"Vapor Phase Fourier Transform Infrared Spectrometric Determination Of Carbonate In Sediments"
Analyst 1998 Volume 123, Issue 9 Pages 1817-1822
Amparo P&eacute;rez-Ponce, Jose M. Garrigues, Salvador Garrigues and Miguel de la Guardia

Abstract: A rapid, sensitive and direct procedure for the determination of carbonate in sediments based on vapor-generation Fourier transform infrared spectrometry is described. A 1 mL volume of hydrochloric acid (0.25 M) was injected into a vessel, heated at 40°C, containing 10 mg of sediment. The CO2 evolved under these conditions was swept by a stream of nitrogen to an infrared gas cell. The flow injection (FI) recordings were registered as a function of time and the areas of the FI recording obtained in the wavenumber range 2500-2150 cm-1 were measured and interpolated in a calibration equation obtained from known amounts of CaCO3 treated in the same way as the samples. The method provided a limit of detection of 0.2 mg of CaCO3, a sampling frequency of 20 h-1 and an RSD of 0.7% for three independent analyzes of 20 mg of sediment. Results obtained for a series of natural sediment samples compared well with those obtained using a back-titrimetric reference method.
Carbonate Spectrophotometry Gas phase detection

"Sample Analysis By Online Isotope-dilution Inductively Coupled Plasma Mass Spectrometry"
J. Anal. At. Spectrom. 1989 Volume 4, Issue 8 Pages 761-766
Alexandra L&aacute;sztity, Mikl&oacute;s Viczi&aacute;n, Xioaru Wang and Ramon M. Barnes

Abstract: A system for online isotope-dilution ICP-MS was developed by coupling commercial flow injection instruments with an ICP-MS instrument. The performance of the system was investigated by determination of Pb in various standard reference materials (including soil, sediment, paint, blood and food), with dilution with 206Pb or radiogenic Pb isotope standards. Both steady-state merging and multiple injections were employed, the former being preferred, the precision was 1%.
Lead Mass spectrometry Mass spectrometry Reference material

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

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

"Speciation And Preconcentration Of Trace Elements With Immobilized Algae For Atomic Absorption Spectrophotometric Detection"
J. Anal. At. Spectrom. 1994 Volume 9, Issue 4 Pages 547-551
H. A. M. Elmahadi and Gillian M. Greenway

Abstract: A previously described procedure for the immobilization of Selenestrum capricornutum on controlled-pore glass and its use for the pre-concentration and determination of metal ions by flow injection AAS (Elmahadi and Greenway, Ibid., 1991, 6, 643) was used to immobilize a different alga, Chlamydomonus reinhartii, and to compare its performance with that of the previously immobilized alga. The metal ion solution was passed through a column of the immobilized alga incorporated in a flow injection manifold. The accumulated ions were eluted by injecting the appropriate eluent reagent into a water carrier stream, followed by measurement by AAS. Optimum conditions for the pre-concentration and elution of Cu(II), Ag(I), Cr(III) and Cr(VI) were established (details given). The method was used for the speciation of Cr(III) and Cr(VI) by employing two flow injection manifolds connected together and to determine Cu(II) and Zn(II) in a certified sediment reference material.
Copper(II) Chromium(III) Chromium(VI) Silver(I) Zinc(II) Spectrophotometry Reference material Immobilized algae Speciation Optimization Controlled pore glass Preconcentration

"Determination Of Antimony By Continuous Hydride Generation Coupled With Nondispersive Atomic Fluorescence Detection"
J. Anal. At. Spectrom. 1995 Volume 10, Issue 11 Pages 969-974
Alessandro D'ulivo, Leonardo Lampugnani, Giovanna Pellegrini and Roberto Zamboni

Abstract: A sensitive method for the determination of Sb at ultratrace levels was developed by coupling continuous hydride generation with non-dispersive atomic fluorescence detection. A miniature argon-hydrogen diffusion flame was employed as the atomizer and a commercially available electrodeless discharge lamp as the light source, One of the main problems was the scattering signal generated by small droplets of solution which markedly deteriorated the signal-to-noise ratio. A simple way to remove the scattering signal was to operate under mild reaction conditions in order to minimize droplet formation. Under the optimized conditions, a limit of detection of 22 pg cm(-3) of Sb (3s of the blank) was achieved, with a precision of 1.2% at the 5 ng cm(-3) level and the calibration graphs were linear over more than 4 decades of concentration, L-Cysteine was employed both in the pre-reduction step and in the control of the interference effects arising from concomitant elements and acid mixtures, The analytical procedure was applied to the determination of Sb in certified reference materials of sediments, metallic copper and riverine water. (29 References)
Antimony Fluorescence Optimization Reference material Volatile generation Interferences Ultratrace Volatile generation

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

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

"Analysis Of Geological Materials For Bismuth, Antimony, Selenium And Tellurium By Continuous-flow Hydride-generation Inductively Coupled Plasma Mass Spectrometry. 2. Methodology And Results"
J. Anal. At. Spectrom. 1997 Volume 12, Issue 1 Pages 103-106
GWENDY E. M. HALL and JEAN-CLAUDE PELCHAT

Abstract: The apparatus and procedure for removal of mutual interference were as described in Part 1 (Ibid., 1997, 12, 97). Sample digestion with aqua regia gave complete recovery of Bi, but some matrices required digestion with HF/HClO4/HNO3/HCl to obtain full recoveries of Te, Se and Sb. The analytes were separated from some potentially interfering elements (e.g., Co, Cu and Ni) by coprecipitation on lanthanum hydroxide. Results are presented for 18 of the Chinese GSD and GSR stream sediment and rock standard reference materials. RSD were in the range 3-8% and the detection limits were 1 µg/kg for Bi and Te and 6 µg/kg for Sb and Se.
Antimony Bismuth Selenium Tellurium Sample preparation Mass spectrometry Detection limit Coprecipitation Interferences Reference material

"Flow Injection Online Sorption Separation And Preconcentration With A Knotted Reactor For Electrothermal Atomic Absorption Spectrometric Determination Of Lead In Biological And Environmental Samples"
J. Anal. At. Spectrom. 1997 Volume 12, Issue 4 Pages 459-464
XIU-PING YAN and FREDDY ADAMS

Abstract: Fish muscle was digested with 65% (w/w) HNO3, the digest was heated with 70% (w/w) HClO4 in a PTFE pressure vessel, the product was evaporated to near-dryness, and the residue was dissolved in water. Soil or sediment was digested with 40% (w/w) HF plus 65% HNO3, the digest was heated with 70% HClO4 in a PTFE pressure vessel, and the product was diluted with water. Diagrams of the flow injection manifold are presented; it incorporated a laboratory-made PTFE knotted reactor (100 cm x 0.5 mm i.d.) on the walls of which the Pb - diethyl phosphorodithioate complex was sorbed at pH 0.5-3.5 before elution with 35 µL of ethanol and transport to a pyrolytically coated GF without platform. The determination was carried out at the same time as the subsequent pre-concentration cycle. An enhancement factor of 125 was achieved, and the detection limit for Pb was 4.8 ng/l. The RSD (n = 11) at 0.5 µg/l of Pb was 2.1%. The results for standard reference materials agreed well with the certified values.
Lead Sample preparation Spectrophotometry Sample preparation Preconcentration Knotted reactor Reference material pH Complexation Solid phase extraction

"Ion-spray Mass Spectrometry - Mass Spectrometry: Quantitation Of Tributyltin In A Sediment Reference Material For Trace Metals"
Anal. Chem. 1989 Volume 61, Issue 20 Pages 2320-2322
K. W. Michael Siu, G. J. Gardner, and S. S. Berman

Abstract: The reference material, viz, PACS-1, was sonicated with methanol - 10 M HCl (2:1) and extracted with 2,2,4-trimethylpentane, and the extract was diluted with methanolic 1 mM ammonium acetate. Alternatively, the sample was sonicated with butan-1-ol and the extract was likewise diluted. The solution were delivered to the ion-spray source by flow injection. Detection was by selected-ion monitoring of the daughter - parent pair at m/z 179/291. The result of 1.29 ppm with a standard deviation (n = 5) of 0.07 ppm was in close agreement with the certified value.
Tributyltin Sample preparation Mass spectrometry Extraction Dilution Reference material

"Use Of Saccharomyces Cerevisiae In Flow Injection Atomic Absorption Spectrometry For Trace Metal Preconcentration"
Anal. Chem. 1994 Volume 66, Issue 9 Pages 1462-1467
Angel Maquieira, Hayat A. M. Elmahadi, and Rosa Puchades

Abstract: Freeze-dried yeast was washed with CHCl3 and hot water, digested with 0.1 M HNO3/HClO4 (1:1) on a steam bath for 30 min. Ethanol was added dropwise and the resulting solution was diluted with water and adjusted to pH 7 with 2 M NaOH. The solution was treated with phosphate buffer solution of pH 5.5, 6.5, 7.5 or 8.5 before the addition of glutaraldehyde-treated controlled pore glass. Immobilization proceeded for 24 h at 4°C under N2, the glass was filtered off and air-dried. Immobilization was unsatisfactory at pH 8.5 and slightly less effective at pH 5.5 than at pH 6.5 or 7.5. Methacrylate columns (4 cm x 2.5 mm i.d.) of the yeast-treated glass were evaluated for the concentration of trace Cd, Zn, Cu(II), Pb(II) and Fe(III) ions from 0.1 M phosphate buffer of pH 6.5. The solution was applied to the column; elution was effected with acid and the metal ions were determined by AAS (details given). Zn and Cu(II) were eluted by 0.1 M HNO3, Pb(II) and Cd by 0.5 M HNO3 and Fe(II) by 0.5 M HClO4/HNO3 (1:1). Linear ranges extended up to 1500 ng/ml (Pb) and the detection limits were 0.1 (Zn) to 8.0 ng/ml (Pb). RSD (n = 10) were 2.6%. The method was used to determine Cu and Cd in sediment.
Cadmium Zinc Copper(II) Lead(2+) Iron(III) Spectrophotometry Preconcentration Controlled pore glass

"Speciation Of Mercury In Soils And Sediments By Thermal Evaporation And Cold Vapor Atomic Absorption"
Fresenius J. Anal. Chem. 1994 Volume 350, Issue 1-2 Pages 18-20
G. Bombach, K. Bombach and W. Klemm

Abstract: Evaporation studies of mercury in several chemical compounds, soils, and sediments with a high content of organic matter indicate that a quantitative release is possible at temperatures as low as 400°C. The desorption behavior from a gold column is not influenced. Only from samples with a thermal prehistory, such as brown coal ash, did mercury evaporate at higher temperatures. Qualitative conclusions can be derived about the content of metallic mercury as well as mercury associated with organic matter or sulfide. A comparison of the analytical results obtained by using the evaporation technique or by dissolving using a mixture of concentrated HCl and HNO3 shows good agreement; the advantages of the evaporation technique are obvious at very low mercury concentrations.
Mercury Sample preparation Spectrophotometry Volatile generation Heated reaction Speciation Volatile generation

"Distillation, Online RP C18 Preconcentration And HPLC-UV-PCO-CVAAS As A New Combination For The Determination Of Methylmercury In Sediments And Fish Tissue"
Fresenius J. Anal. Chem. 1997 Volume 357, Issue 4 Pages 439-441
Ralf Eiden, Falf Falter, Barbara Augustin-Castro, Heinz Friedrich Scholer

Abstract: Distillation as a way of sample digestion has been combined with on-line RP C18 pre-concentration and HPLC-UV-PCO-CVAAS (high performance liquid chromatography - ultra violet - post column oxidation - cold vapor atomic absorption spectrometry) for the determination of methylmercury at background levels in sediments, soils and fish tissue. To prove the accuracy of this method, it was applied to sediment and fish tissue reference materials. The results correspond with the reference values within their error ranges. Excellent recoveries (92-95%) were obtained for the sediment samples by means of the standard addition method. The standard deviations of the sediment samples were within an acceptable range (7.2-12.5%), those of the fish samples were substantially lower (3.4-5.0%). The detection limit is 0.04 ng/g for 1 g sample weight.
Methylmercury ion HPLC Spectrophotometry C18 UV reactor Preconcentration Volatile generation Speciation Volatile generation Photochemistry

"Speciation Of Antimony By Atomic Absorption Spectrometry. Applicability To Selective Determination Of Antimony(III) And Antimony(V) In Liquid Samples And Of Bioavailable Antimony In Sediments And Soil Samples"
Microchim. Acta 1992 Volume 109, Issue 1-4 Pages 149-155
Mar&iacute;a Beatriz de la Calle Gunti&ntilde;as, Yolanda Madrid and Carmen C&aacute;mara

Abstract: Speciation of Sb(III) and Sb(V) by AAS in liquid samples was evaluated by investigating the (i) determination of Sb(III) and SbV in water by selective extraction with lactic acid - malachite green by graphite-furnace AAS; (ii) determination of Sb(III) and Sb(V) by hydride-generation - AAS coupled to flow injection, batch and continuous-flow systems; (iii) mineralization methods for soil samples. Different sample pre-treatments were evaluated in terms of recovery of total Sb and the ability to speciate Sb(III) and SbV by slurry formation in soil and sediments. The graphite-furnace extraction method was the most convenient method for speciation of Sb(V) and Sb(III) in surface and seawater.
Antimony(3+) Antimony(5+) Spectrophotometry Spectrophotometry Speciation Slurry

"Normal-phase High Performance Liquid Chromatography With UV Irradiation, Morin Complexation And Fluorescence Detection For The Determination Of Organotin Pesticides"
J. Chromatogr. A 1992 Volume 609, Issue 1-2 Pages 195-203
Joan A. St&auml;b, Marcel J. M. Rozing, Bert van Hattum and Wim P. Cofino, and Udo A. Th. Brinkman

Abstract: Surface waters were extracted with n-hexane, while soil and sediments were Soxhlet-extracted for 12 h with hexane - acetone (9:1). The extracts were analyzed on a column (15 cm x 4.6 mm) of cyanopropyl-bonded silica (3 µm) with n-hexane - THF - acetic acid (48:1:1) as mobile phase (1 mL min-1). Post-column derivatization was effected by UV irradiation followed by reaction with ethanolic 0.0025% morin (0.15 mL min-1) in a reaction coil and fluorimetric detection at 495 nm (excitation at 430 nm). The detection limits were 0.02 to 0.03 µg L-1 in water and 0.2 to 0.3 µg g-1 in solids. The mean recoveries from water were between 61 and 114% and from the solids between 44 and 135% for three such compounds.
Tin, organic HPLC Fluorescence Sample preparation Post-column derivatization Complexation

"Study On Stable Coatings For Determination Of Lead By Flow Injection Hydride Generation And In Situ Concentration In Graphite-furnace Atomic Absorption Spectrometry"
Spectrochim. Acta B 1996 Volume 51, Issue 11 Pages 1425-1433
H. O. Haug

Abstract: Both W- and Zr-coated graphite tubes are recommended for the trapping and concentration of Pb after hydride generation, and can be used for more than 400 trapping-atomization cycles. The overall trapping efficiency in W-coated tubes was 71%. The detection limit for Pb at 283.3 nm with use of a W-coated tube was ~e;0.25 ng, and the RSD (n = 10) at 2 ng/ml (0.5 mL sample loop) was better than 3%. The result for a sediment reference material was in reasonable agreement with the certified value. The sensitivity is currently limited by the reagent blank.
Lead Spectrophotometry Volatile generation Reference material Volatile generation

"Analytical Aspects Of Copper Binding By Humic Substances In Reservoir Sediments"
Anal. Proc. 1983 Volume 20, Issue 3 Pages 125-127
J. Tovar-Grau, C. L. Graham, M. H. B. Hayes

Abstract: Humic substances have the ability to form complexes with many metal ions. Of special concern is the formation of water-soluble conipleses of the so-called fulvic acids, because they may increase the concentration of metals in natural waters and soils to levels that are in excess of their normal solubilities. The precise structure of humic acids in unknown, and in any case, varies from source to source, but alcoholic and phenolic hydroxyls, carboxyl and carbonyl groups are known to be present in all types. Undoubtedly, the complexing properties are largely attributable to the phenoxy and carboxyl functional groups. In this study, humic substances were chemically isolated from organic material collected on the filter beds of certain water treatment plants, operated by the North West Water Authority (Pennine Division). Humic and fulvic acids were separated into several relative molecular mass fractions, in tlie range < 1 x 10^4 - 7 x 10^4, by ultrafiltration. These fractions were purified by means of dialysis, re-precipitation' and extraction into butan-1-01.
Copper Fluorescence

"Multielement Determination Of Trace-elements In Sediment Sample By Inductively-coupled Plasma-mass Spectrometry With Microsampling Technique"
Bull. Chem. Soc. Jpn. 1996 Volume 69, Issue 12 Pages 3505-3511
Eiji Fujimori, Rong Wei, Hideyuki Sawatari, Koichi Chiba, and Hiroki Haraguchi*

Abstract: A discrete microsampling technique for multielement determination of trace elements by inductively coupled plasma mass spectrometry has been investigated for analyzes of samples containing large amounts of matrix elements. In the technique, 100 µl of the sample solution was introduced into the plasma by using a six-way valve, and 10 elements were detected in peak hopping mode during a single mass range scan. As a result, a transient peak profile of the signal for each element was observed at each m/z position. The peak area measurement method was established for the quantitative analysis. The optimization of instrumental conditions and matrix effects in multielement determination were investigated in detail. The discrete microsampling technique was found to reduce some memory effects due to matrices in ICP-MS. The present system was applied to the analyzes of standard sediment sample and 30 elements at the µg g-1 level were successfully determined without matrix separation. 18 References
Metals Mass spectrometry Interferences Multicomponent Optimization Reference material

"Establishment And Analytical Quality Control Of Laboratories For Hg Determination In Biological And Geological Samples In The Amazon, Brazil"
Cienc. Cult. 1998 Volume 50, Issue 4 Pages 255-260
WANDERLEY R. BASTOS, OLAF MALM, WOLFGANG C. PFEIFFER, DAVID CLEARY2

Abstract: During the past 20 yr significant amounts of Hg were released in the Amazonian environment due to gold mining activities. Several Brazilian and foreign research groups were studying the region, always facing difficulties regarding preservation and transfer of the collected samples from the field to the anal. labs. Aiming to solve these problems two high quality Hg anal. labs. were established in the region. One is located at Fundacao Esperanca (FE, Santarem, PA), a medical assistance foundation and the other at the Universidade Federal de Rondonia (UNIR), Porto Velho, RO. Their main equipment is: Atomic absorption spectrophotometers for Hg anal. (Flow Injection Mercury System-FIAS 400 with automatic samples-AS90-Perkin Elmer) and a microwave oven digestion system (MDS-2000-CEM). Technicians and researchers were trained in several aspects like environmental and human sampling, digestion methods and Hg anal. for biotic and abiotic materials. This training as well as the installation of the mentioned labs. were the responsibility of the Universidade Federal do Rio de Janeiro (UFRJ). Intercalibration exercises were performed between several labs.: Environmental Medicine of Odense University (Denmark), Center de Toxicologie du Quebec, Canada and Occupational Health Sciences (Health-Canada). In the last 18 mo the FE lab. joined the Hg urine anal. intercalibration program of the Lab. of the Center of Toxicol. in Quebec, Canada, reaching accurate results. To date both Amazonian labs. are able to analyze several different materials: Sediment, soil, fish, urine, hair and blood. The FE lab. is becoming more specialized in human samples such as urine, blood and hair, while UNIR lab. deals with environmental samples such as fish, sediment and soil.
Mercury Spectrophotometry Sample preparation FIAS-400 FIMS

"Acid-persulfate Digestion Procedure For Determination Of Phosphorus In Sediments"
Commun. Soil Sci. Plant Anal. 1987 Volume 18, Issue 4 Pages 359-369
Nelson, N.S.

Abstract: To sediment samples in culture tubes were added water and 5.5 M H2SO4 followed by solid K2S2O8 and the mixture was heated in an autoclave for 1 h at 130°C. The tubes were then set aside overnight, after which the supernatant solution were diluted with aqueous K2SO4 - H2SO4 for determination of PO43--P by a continuous-flow adaptation of the method of Murphy and Riley (Anal. Abstr., 1963, 10, 1219). This safe method released a large fraction of the P released by the hazardous HClO4 digestion method. Total P in stormflow sediments determined by HClO4 digestion can be predicted with acceptable accuracy from P determined by acid persulfate digestion provided that homogeneous replicate sub-samples are analyzed.
Phosphorus Sample preparation

"Determination Of Aluminum In Sediments By Flow Injection Spectrophotometry"
Fenxi Huaxue 1996 Volume 24, Issue 4 Pages 456-458
Zhao, Z.Y.

Abstract: Dried sample (0.5 g) was mixed with 15 mL concentrated HNO3 and heated to near dryness. The residue was treated with 3 mL HClO4, heated until fuming commenced and the residual solution was diluted to 50 mL with 0.5% HNO3. Portions of the resulting solution were injected into a carrier stream (4 ml/min) of a flow injection manifold (schematic shown), mixed with 0.01% aluminum coloring reagent (1.9 ml/min) and the absorbance was measured at 590 nm. The calibration graph was linear up to 40 µg/ml. The RSD (n = 13) was 0.8% for 4.5 µg/ml of Al. Results agreed with those obtained by AAS.
Aluminum Spectrophotometry Spectrophotometry

"Study On The Oxidation Chemiluminescence Of Lucigenin System Sensitized By Alcohol And Its Application"
Fenxi Shiyanshi 1995 Volume 14, Issue 3 Pages 11-13
Gong, L.X.;Yu, Z.A.

Abstract: Pb(II) solution (53 l) was injected into a carrier stream of water (2.5 ml/min) in a home-made reversed-flow-injection chemiluminescence apparatus. The carrier stream was mixed with a reagent stream (prepared from 12 mL of 10 M lucigenin, 8 mL of 95% ethanol and 20 mL of 1 M H2O2), at 2.5 ml/min, in a reaction tube (30 cm long) then with 2 M NaOH in a reaction tube (15 cm long) before recording the chemiluminescence. The relationship between chemiluminescence intensity and concentration was linear for 0.3-80 g/ml of Pb with a detection limit of 0.1 g/ml. The RSD was 2.3%. Interferences from Co(II), Ni(II), Cd(II), Cu(II), Zn(II) and Sb(III) were masked. With the addition of 40% ethanol the sensitivity increased by 2.7-fold. The method was applied to the assay of synthetic water samples and sediments.
Lead Chemiluminescence

"Investigation Of The Enhancement Sensitivity Effect Of Some Oxidants On Lead In Flow Injection Hydride-generation AAS"
Guangpuxue Yu Guangpu Fenxi 1992 Volume 12, Issue 3 Pages 75-82
Wei, J.H.;Lin, F.;Wang, X.S.

Abstract: For the determination of Pb, GSD-5 reference material was digested with concentrated HCl and the digest was evaporated to near dryness. The residue was further treated with HNO3 and evaporated to near dryness. The residue was dissolved in water and the solution was mixed with concentrated HCl, boiled and cooled. The solution was filtered, mixed with aqueous 6% K3Fe(CN)6 and diluted with water. The solution was analyzed by flow injection hydride generation AAS (optimum conditions given). The results obtained compared well with the literature value. The mechanism was studied of the enhancement in the sensitivity of the determination of Pb by oxidants, e.g., K3Fe(CN)6, H2O2, K2Cr2O7 and (NH4)2S2O8. The sensitivity increase caused by K3Fe(CN)6 was higher than that obtained with the other oxidants.
Lead Sample preparation Spectrophotometry Optimization Sensitivity Reference material Volatile generation Volatile generation

"Flow Injection Analysis With The Copper(I)-bathocuproine - Triton X-100 System - Rapid Determination Of Trace Copper In Sediments"
Haiyang Xuebao 1987 Volume 9, Issue 1 Pages 51-55
Yuan, Youxian

Abstract: Copper was determined by flow-injection spectrophotometry with a carrier stream containing Tritron X-100, bathocuproine, and hydroxylamine as reducing agent in acetate buffer at pH 4.5. The reaction tube was 0.8 mm i.d. and 140 cm long. The flow rate was 2.5 mL/min. The sample injection volume was 50 mL. The detection wavelength is 479 nm. The working curve is linear for 0-6 mg/mL; the detection limit is 0.05 mg/mL. The system can analyze 100 samples/h. Trace copper was determined in marine sediments with relative standard deviation of 3.3-5.0% and recoveries of 90-100%.
Copper Spectrophotometry Complexation Surfactant Triton X

"Catalytic Determination Of Osmium By Using Flow Injection Analysis"
Huaxue Tongbao 1988 Volume 51, Issue 10 Pages 41-42
He, X.;Cai, Y.;Gong, H.;Hu, Z.D.

Abstract: The aqueous sample solution, 4 mM KIO3 plus 0.2 M Na2B4O7 - 0.2 M NaOH (pH 9 to 11.5), and 0.2 mM α-naphtholphthalein were separately injected into a mixing coil at 80°C and the mixture then passed to a detector unit. The recorded peak voltage was rectilinearly related to Os concentration. between 0.01 and 0.12 µg mL-1 under the specified operating conditions. Tolerance levels for 16 cations are listed; Ru(III), Rh(III), Ir(IV) and Mn(II) interfered and needed to be separated before analysis. Recoveries for an ore concentrate and a chloride sediment containing ~4 kg t-1 and 0.5 kg t-1 of Os, respectively, were 96 to 100.5%.
Osmium Spectrophotometry Catalysis Heated reaction Interferences

"Sulfur And Nutrient Analysis Of Sediments And Sediment Interstitial Water"
Int. J. Environ. Anal. Chem. 1988 Volume 34, Issue 2 Pages 109-117
Ripl, W.;Michel, J.

Abstract: An analytical system is described for determination of S, PO43- and NO3- in sediments and water. The system includes sampling, sample pre-treatment and digestion and flow injection analysis by standard and previously described methods. For the determination of SO42-, the calibration graph was rectilinear from 10 to 40 mg L-1 with coefficient of variation of 2.5%. Results are presented for PO43- and NO3- determined in interstitial water.
Sulfate Sulfur Phosphate Nitrate Sample preparation

"Using FIMS To Determine Mercury Content In Sewage Sludge, Sediment And Soil Samples"
J. Autom. Methods Manag. Chem. 1996 Volume 18, Issue 6 Pages 221-223
TIEZHENG GUO and J&Ouml;RN BAASNER

Abstract: Sewage sludge (0.01 g) spiked with Hg was weighed into a digestion flask, moistened with a few drops of water and 21 mL HCl and 7 mL HNO3 were added. Digestion was carried out in accordance with DIN 38414, Part 12. The cooled solution was diluted to 100 mL with water. A portion (100 µL) of 0.5% K2Cr2O7 in HNO3/H2O (1:1) was added to 1 mL supernatant and the mixture was diluted to 10 mL. Samples were reduced with 1.5% SnCl2 in 1% HCl prior to Flow injection Mercury Systems (FIMS) analysis. Recoveries of Hg in spiked sewage sludge were 96-100% and analyzes of standard reference samples were in agreement with certified values. RSD (n = 3) were ~2% for 10 µg/l of Hg. Results obtained by FIMS were in agreement with values obtained by FIA generation of Hg vapor and AAS.
Mercury Spectrophotometry Sample preparation FIMS Volatile generation Method comparison Reference material Volatile generation

"Simultaneous Measurement Of Oxide, Manganese, Iron, Iodide, And Sulfide In Marine Pore Waters With A Solid-state Voltammetric Microelectrode"
Limnol. Oceanogr. 1998 Volume 43, Issue 2 Pages 325-333
Luther, George W., III, Paul J. Brendel, Brent L. Lewis, Bj&oslash;rn Sundby, Lucie Lefran&ccedil;ois, Norman Silverberg, and Donald B. Nuzzio

Abstract: A solid-state Au/Hg voltammetric microelectrode was used to measure, simultaneously and with millimeter spatial resolution, the vertical distributions of O2, Mn2+, Fe2+, HS-, and I- in the pore water of sediments from the Canadian continental shelf and slope. The electrode was used shipboard to analyze undisturbed sediment cores and in a sediment mesocosm to determine the three-dimensional distribution of redox species in the sediment surrounding an actively irrigated worm burrow. In cores from Emerald Basin and Cabot Strait, O2 disappeared and Mn2+, Fe2+, and HS- appeared in the vertical sequence predicted on the basis of thermodynamics. In a core from the Scotian slope, O2 disappeared at ~14-mm depth but Mn2+ was not detected over the 50-mm depth examined with the probe. In all three cores, I- was detected in the pore water below the oxygen-penetration depth. In none of the cores did the distributions of O2 and Mn2+ overlap. The thickness of the layer within which neither O2 nor Mn2+ could be detected ranged from 8 to 40 mm; we suggest that nitrate, not oxygen, is used to oxidize Mn2+. The upwarddirected Mn2+ gradients of 3.5 and 10 mol mm4 in the Emerald Basin and Cabot Strait sediments, respectively, drive manganese fluxes that are more than one order of magnitude lower than the O2 fluxes, which are estimated at 4-S mmol mm 2 d-1. The three-dimensional distributions of solutes in the pore water in the sediment surrounding an irrigated worm burrow demonstrate that both the O2-penetration depth and the depth where Mn2+ is first detected are deeper in the vicinity of the worm burrow than away from it. This is consistent with the notion that irrigation brings oxygenated water into the worm tube, allowing oxygen to diffuse across the burrow wall into the sediment and react with Mn2+ and other reduced porewater constituents. Three-dimensional heterogeneity in porewater composition cannot be detected by conventional one-dimensional coring and slicing techniques. Because these latter techniques average the porewater composition in a large volume of sediment, they may indicate that the distributions of individual species overlap when in fact they do not.
Oxide Manganese Iron Iodide Sulfide Voltammetry Electrode Simultaneous analysis

"Strategies For The Rapid Characterization Of Metals And Organic Pollutants In Solid Wastes And Contaminated Soils By Using Mass Spectrometry"
Trends Anal. Chem. 1998 Volume 17, Issue 5 Pages 263-272
Miguel de la Guardia and Salvador Garrigues

Abstract: Hyphenated techniques involving mass spectrometry (MS) such as ICP-MS, GC-MS and LC-MS are the most powerful tools for both qualitative and quantitative characterization of metals and organic pollutants in previously dissolved or extracted samples. However a considerable analytical effort is required in developing simple and general sample preparation strategies for the complete characterization of toxic substances in solid wastes and soils. This article gives a critical review, with 44 references, of the state-of-the-art and future perspectives for rapid procedures to evaluate the pollution of soils and sediments, also considering new alternatives like flow injection anal.-MS and direct sampling MS.
Metals Organic compounds Mass spectrometry Reverse Speciation Optimization