Electrothermal atomic absorption spectrometric determination of trace elements in high-purity silver after total and partial reductive separation of the matrix

A sensitive and reliable ETAAS determination of metal traces in high purity silver after total (Bi, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb) and partial (As, Hg, Sb, Se) separation of the matrix with ascorbic acid is described. The temperature program is optimized for analyte determination in ascorbic acid media and in 1% silver solution.     

Electrothermal atomic absorption spectrometric determination of trace elements in high-purity silver after total and partial reductive separation of the matrix

A sensitive and reliable ETAAS determination of metal traces in high purity silver after total (Bi, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb) and partial (As, Hg, Sb, Se) separation of the matrix with ascorbic acid is described. The temperature program is optimized for analyte determination in ascorbic acid media and in 1% silver solution.     

Electrothermal atomic absorption spectrometric determination of aluminum in blood serum

An aerosol-generating device is used for sample application. Precision ranges from 2.5 to 8.0% and recoveries of 30 and 100 μg l^-1 added to each of five samples ranged from 95 to 105%. Correlation with a slightly different method gave a least-squares fit of y = 1.02x – 1.35 μg l^-1. The technique described is satisfactory for studying aluminum toxicity in dialysis encephalopathy and Alzheimer's Disease.     

Graphite furnace atomic absorption spectrometric determination of iridium,rhodium and ruthenium in high-purity platinum after matrix extraction

Ir, Rh and Ru are separated from a large excess of platinum by extraction with isoamyl alcohol-isobutyl methyl ketone mixture. Graphite furnace atomic absorption spectrometry using the method of standard addition is then used to determine the metals with satisfactory precision and accuracy.     

Extraction system for flame atomic absorption spectrometric analysis of high-purity bismuth compounds

Two new ligands, 2-(2-benzoxazolyl)cyanoacetaldehyde and 2-(2-benzoxazolyl)malonaldehyde are proposed for extractive separation and preconcentration. The extraction behaviour of Ag, Bi, Cd, Co, Cu, Fe, Mn, Mo, Ni, Pb, Pd, Pt, Sb and Zn with respect to pH, salt concentration and the presence of various masking agents was studied. A simple extraction procedure for the analysis of high-purity bismuth compounds was developed.     

Electrothermal atomic absorption spectrometric determination of cobalt, copper, lead and nickel traces in aragonite following flotation and extraction separation

A method of determination of Co, Cu, Pb and Ni in nanogram quantities from aragonite is presented. Flotation and extraction of Co, Cu, Pb and Ni is suggested as methods for elimination matrix interferences of calcium. The method of flotation is performed by iron(III) hexamethylenedithiocarbamate, Fe(HMDTC)(3), as a colloid precipitate collector. The liquid-liquid extraction of Co, Cu, Pb and Ni is carried out by sodium diethyldithiocarbamate, NaDDTC, as complexing reagent into methylisobutyl ketone, MIBK. The electrothermal atomic absorption spectrometry (ETAAS) is used for determination of analytes. The detection limits of ETAAS followed by flotation are: 7.8 ng.g(-1) for Co, 17.1 ng.g(-1) for Cu, 7.2 ng.g(-1) for Pb and 9.0 mug.g(-1) for Ni. The detection limits of ETAAS followed by extraction are found to be: 12.0 ng.g(-1) for Co, 51.0 ng.g(-1) for Cu, 24.0 ng.g(-1) for Pb and 21.0 ng.g(-1) for Ni.     

Electrothermal atomic absorption spectrometric techniques for the determination of zinc and copper in microliter and submicroliter volumes of aqueous and serum matrices

Two electrothermal atomic absorption techniques which provide linear working functions over wide concentration ranges, and are suitable for the determination of zinc and copper in aqueous and 10-fold diluted blood serum matrices are evaluated. The first technique is based on modification of the furnace tube to provide a significant decrease of the atomic absorption signal when microliter and larger volumes of sample are injected. The second technique involves a delivery system capable of dispensing micro- and submicroliter sample volumes to the furnace tube. The precision of the two techniques is about 98%.     

Electrothermal atomic absorption spectrometric determination of cobalt in steel after chloroform extraction of its 1-nitroso-2-naphthol complex

Direct determination of μg g^-1 levels of cobalt in steels and corrosion products by electrothermal atomic absorption is difficult because of suppression of the cobalt signal by mineral acids and other metals. Extraction or cobalt with 1-nitroso-2-naphthol into chloroform in the presence of citrate overcomes this problem. Samples (0.4–10 mg) may be dissolved in a variety of acids, and a detection limit of 0.005 μg g^-1 in the chloroform extract is obtained.     

Electrothermal atomic absorption spectrometric determination of germanium in soils using ultrasound-assisted leaching

A procedure for determining germanium in soil samples using electrothermal atomic absorption spectrometry is discussed. The analyte is leached from the solid sample by the addition of 1 ml of concentrated hydrofluoric acid to 10-300 mg of sample, and the mixture is then submitted to a 10 min ultrasonic treatment. After adding 0.4 g boric acid and 3 ml concentrated hydrochloric acid, germanium is extracted into 1 ml chloroform and back-extracted into an aqueous phase containing (0.05%, w/v) nickel nitrate. Ten micro liter of aqueous phase are introduced into the atomizer and the analytical signal from germanium is obtained using a fast-heating cycle. The detection limit, calculated using three times the standard error of estimate (s_y/x) of the calibration graph, is 0.015 μg g⁻¹. The reliability of the procedure is verified by analyzing several certified reference materials.     

Extraction and atomic absorption spectrometric determination of bismuth with electrothermal atomization

Summary A sensitive method for the extraction and atomic absorption spectrometric measurement with electrothermal atomization has been developed for the determination of bismuth in tea and orchard leaves. Bismuth is extracted into m-xylene as diethyldithiocarbamate complex. 2.5–3.0 l/min of argon flow rate, 650–800° C of ashing temperature and 2,200–2,600° C of atomization temperature were the best experimental conditions. A detection limit of 0.02 ng was obtained with a precision of 2–7% and minimal interference effects.Paper read at the meeting of the Japan Society for Analytical Chemistry, October 1978     

Electrothermal atomic absorption spectrometric determination of arsenic in essential lavender and rose oils

Analytical procedures for electrothermal atomic absorption spectrometric (ETAAS) determination of arsenic in essential oils from lavender (Lavendula angustifolia) and rose (Rosa damascena) are described. For direct ETAAS analysis, oil samples are diluted with ethanol or i-propanol for lavender and rose oil, respectively. Leveling off responses of four different arsenic species (arsenite, arsenate, monomethylarsonate and dimethylarsinate) is achieved by using a composite chemical modifier: l-cysteine (0.05 g l⁻¹) in combination with palladium (2.5 μg) and citric acid (100 μg). Transverse-heated graphite atomizer (THGA) with longitudinal Zeeman-effect background correction and ‘end-capped’ graphite tubes with integrated pyrolytic graphite platforms, pre-treated with Zr-Ir for permanent modification are employed as most appropriate atomizer. Calibration with solvent-matched standard solutions of As(III) is used for four- and five-fold diluted samples of lavender and rose oil, respectively. Lower dilution factors required standard addition calibration by using aqueous (for lavender oil) or i-propanol (for rose oil) solutions of As(III). The limits of detection (LOD) for the whole analytical procedure are 4.4 and 4.7 ng g⁻¹ As in levender and rose oil, respectively. The relative standard deviation (R.S.D.) for As at 6-30 ng g⁻¹ levels is between 8 and 17% for both oils. As an alternative, procedure based on low temperature plasma ashing in oxygen with ETAAS, providing LODs of 2.5 and 2.7 ng g⁻¹ As in levender and rose oil, respectively, and R.S.D. within 8-12% for both oils has been elaborated. Results obtained by both procedures are in good agreement.     

Hydride generation atomic absorption spectrometric determination of bismuth after separation and preconcentration with modified alumina

A simple and sensitive method has been developed for the trace determination of bismuth in aqueous samples by a combination of solid‐phase extraction and hydride generation atomic absorption spectrometry. The method is based on the use of a column packed with 2‐mercaptobenzothiazole immobilized on sodium dodecyl sulfate coated alumina. Different parameters influencing the separation and preconcentration of bismuth such as pH, sample volume, type, and concentration of eluent, and the flow rate of sample and eluent were studied. A sample volume of 500.0 mL resulted in a preconcentration factor of 100. The precision (relative standard deviation, N = 10) at the 300 ng/L level and the limit of detection (3s) were found to be 2.3% and 12 ng/L, respectively. The developed method was successfully applied to the determination of bismuth in natural water samples and two certified reference materials.     

Electrothermal atomization atomic absorption spectrometric determination of trace metals in uranium-plutonium fuel materials

Summary Atomic absorption spectrometric methods using the electrothermal mode of atomization developed for the determination of Ag, Be, Ca, Cd, Cr, Co,Cu, Fe, Li, Mn, Na, Ni, Sn and Zn in (U, Pu) solution with 4% plutonium have been described. The carbon rod atomizer has been adapted for glove box operation to enable handling of plutonium containing solution samples. Multielement solution standards with graded concentrations of the analytes and fixed concentration of the matrix are used in the standardization process. Nanogram to sub-nanogram quantities of the analytes have been determined with a precision of better than 9% RSD using 5 l of the sample aliquots.

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Bestimmung von Metallspuren in Uran-Plutonium-Kernbrennstoffen mit Hilfe der ETA-AAS

     

Electrothermal atomic absorption spectrometric determination of lithium,sodium, potassium and copper in uranium without preliminary chemical separation

Graphite furnace atomization is used for the direct determination of Li (0.25–4 ppm), Na (8–70 ppm), K (20–300 ppm) and Cu (0.5–25 ppm) in uranium dissolved in nitric acid, with relative standard deviations of 4–9%. Only iron seriously depresses the signals from the alkali metals.     

Electrothermal atomic absorption spectrometric determination of chromium,iron and nickel in lithium metal

Graphite-furnace atomic absorption spectrometry is applied to the determination of traces of Cr, Fe and Ni in lithium metal, after dissolution as lithium chloride. Direct determination is applied to lithium samples containing higher levels of impurities, but determination in pure lithium samples requires preliminary separation by lanthanum hydroxide coprecipitation. With this enrichment, detection limits of 0.02–0.25 μg g^-1 are obtained using 0.5-g samples of lithium. The accuracy of the procedure was checked by analysis of lithium samples by the proposed coprecipitation method, by direct determination, and by determination after extraction, atomic absorption spectrometry being used in all cases.     

Synergic extraction and atomic absorption spectrometric determination of vanadium in silicates

An atomic absorption spectrometric method for the determination of vanadium in silicates is proposed. Samples are digested with aqua regia and hydrofluoric acid in sealed Tenon vessels, iron is eliminated by anion exchange from 8 M hydrochloric acid, and vanadium is extracted synergically with β -isopropyltropolone into di-n-butyl ether in the presence of n-butanol from 0.5 M hydrochloric acid. The extract is aspirated into a nitrous oxide—acetylene flame. Less than 3 mg of iron in the organic extract (15 ml) does not interfere in the determination of 150 μg of vanadium. The results for vanadium in nine standard rock samples (USGS, GSJ and CSRM) agree well with earlier data. The recovery, reproducibility, and accuracy of the proposed method are satisfactory. Vanadium in new standard silicate rocks, GSJ-JB-2 and GSJ-JA-1, was also determined.     

Electrothermal atomic absorption spectrometric determination of trace lead,copper and manganese in aluminum and its alloys without preliminary separation

Graphite-furnace atomic absorption spectrometry is used for the determination of >0.001% of lead, copper and manganese in aluminum and its alloys. The samples are dissolved in hydrochloric acid and analyzed directly after addition of a slight excess of (NH₄)₂ EDTA over aluminum. Sample and standard solutions must contain equal amounts of EDTA.     

Solid phase extraction and graphite furnace atomic absorption spectrometric determination of ultra trace amounts of bismuth in water samples

A simple and reliable method for the selective extraction and determination of bismuth in water as well as alloy samples using octadecyl bonded silica cartridge modified with cyanex 301 and graphite furnace atomic absorption spectrometry is described. Extraction efficiency and influence of sample matrix, optimum amount of extraction ligand, type and least amount of proper eluent and flow rates were evaluated. The limit of detection of the proposed method is 0.01 ng ml(-1). The influence of potential interfering cations in water samples on the recovery of bismuth was investigated. The method was successfully applied to the extraction and determination of bismuth in natural water and alloy samples.     

Flow injection-hydride generation atomic absorption spectrometric determination of selenium, arsenic and bismuth

A simple and robust flow injection system which permits low sample and reagent consumption is described for rapid and reliable hydride generation atomic absorption spectrometric determination of selenium, arsenic and bismuth. The system, which composed of one peristaltic pump and one four channel solenoid valve, used water as the carrier streams for both sample and NaBH₄ solution. Rapid off-line pre-reduction of the analytes was achieved by using hydroxylamine hydrochloride for selenium and a mixture of potassium iodide and ascorbic acid for arsenic and bismuth. Transition metal interference was eliminated with the addition of thiourea and EDTA into the NaBH₄ solution and significant sensitivity enhancement was observed for selenium in the presence of thiourea in the reductant solution. Under optimised conditions, the method achieved detection limits of 0.2 ng mL⁻¹ for Se, 0.5 ng mL⁻¹ for As and 0.3 ng mL⁻¹ for Bi. The method was very reproducible, achieving relative standard deviations of 6.3% for Se, 3.6% for As and 4.7% for Bi, and has a sample throughput of 360 h⁻¹. Successful application of the method to the quantification of selenium, arsenic and bismuth in a certified reference river sediment sample is reported.     

Electrothermal atomic absorption spectrometric determination of lead in high-purity reagents with flow-injection on-line microcolumn preconcentration and separation using a macrocycle immobilized silica gel sorbent

A fully automated procedure for the determination of ng l⁻¹ amounts of lead has been developed using flow injection (FI) online column preconcentration coupled with electrothermal atomic absorption spectrometry (ETAAS). The proposed FI manifold and its operation make possible the introduction of the total eluate volume into the graphite atomizer, avoiding the necessity for optimization of subsampling the eluate. The interference of other heavy metal ions due to competition for active sites of the sorbent is overcome using a highly selective macrocycle immobilized on silica gel (Pb-02). Lead is adsorbed on a microcolumn (50 μl) packed with Pb-02, and after washing the column with dilute nitric acid, air is introduced to remove all solution from the column and connecting tubing. The sorbed analyte is then eluted quantitatively into the graphite tube atomizer, preheated to 100°C, with 36 μl of ETDA solution (0.035 mol l⁻¹, pH 10.5), propelled by air in order to minimize dispersion. The collection efficiency was 77% and with a sample loading flow rate of 3 ml min⁻¹ and a 60 s preconcentration time, the enhancement factor was 77 and the throughput was 17 samples per hour. The relative standard deviation (n = 10) at the 300 ng l⁻¹ level was 2.7%, and the detection limit (3σ) was 0.4 ng l⁻¹. No interference from heavy metals was observed, but ions of Ba²⁺, Sr²⁺ and K⁺ were found to interfere when the concentration ratios of interferent to lead exceeded values of 2000, 20 000 and 200 000, respectively. Quantitative recovery of lead was achieved from sodium, magnesium, aluminum, lanthanum and heavy metal salt solutions. The high selectivity and sensitivity, combined with extremely low blank values, make the proposed technique particularly attractive for the analysis of high-purity reagents, semiconductors and other high-purity materials. Results are presented for the determination of lead in some high-purity reagents.