Determination of thallium by atomic absorption spectrophotometry

Summary The determination of thallium by atomic-absorption Spectrophotometry is described. Many substances interfere with the direct analysis of thallium under the conditions chosen. However, these interferences can be overcome by adding a lithium, potassium, or sodium buffer (5000 ppm). In this way the deviations caused by foreign substances can be reduced to less than ten per cent. Under the same conditions the effect of organic solvents has been studied.

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Zusammenfassung Die Bestimmung von Thallium mit Hilfe der atomaren Absorptionsspektrophotometrie wird beschrieben. Die direkte Bestimmung von Thallium wird im allgemeinen durch viele Fremdionen in höheren Konzentrationen gestört. Durch Verwendung eines Li-, K-, oder Na-Puffers (5000 ppm) können die Störungen auf weniger als 10% herabgesetzt werden. Unter den gleichen experimentellen Bedingungen wird die Wirkung von organischen Lösungsmitteln untersucht.

     

Determination of nonmetals by atomic absorption spectrophotometry

Inorganic anions and organic compounds are determined using conventional atomic absorption apparatus. Several methods are studied in which the desired compound either limits or interferes with the determination or absorption of a metal. A direct relationship is obtained between the absorption by the metal and the amount of substance sought. Substances determined include orthophosphate, sulfate, iodide, sulfide, iodate, glucose, protein, 8-hydroxyquinoline, ethylenediaminetetraacetic acid, and ammonium pyrrolidine dithiocarbamate.     

Determination of magnesium in iron by atomic absorption spectrophotometry

An atomic absorption spectrophotometric method for the determination of 0.001–0.10% magnesium in irons has been proposed. After suitable dissolution of the sample, 1500 p.p.m. of strontium is added to suppress aluminium interference and the solution is atomised in an atomic absorption spectrophotometer. The method is rapid, has high sensitivity, is free from interference and no preliminary separations are required.     

Determination of vanadium in urine by electrothermal atomic absorption spectrometry

After wet ashing of the urine sample with nitric acid, vanadium is chelated with cupferron, extracted into 4-methylpentan-2-one and determined by atomic absorption spectrometry with a pyrolytically-coated graphite furnace atomizer. The sensitivity allows the precise determination of 1–500 μg V l^-1 in urine. The coefficient of variation for triplicate urine measurements is <8% for 10 μg V l^-1.     

Determination of mercury in seawater by cold vapour atomic absorption spectrophotometry

Summary To avoid systematic errors in the sampling and determination of mercury in seawater an integrated sampling-analyzing system has been developed. A 500 ml PTFE-bottle attached to a sampling gear is used as sampling vessel for the cold vapour atomic absorption Spectrophotometry, using nitrogen aeration, SnCl₂ reduction, and preenrichment/ purification by amalgamation on finely dispersed gold. The detection limit of this procedure was found to be 0.5 ng·l^–1 and the coefficient of variation 4% for 1.5 ng·l^–1.

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Bestimmung von Quecksilber im Meerwasser durch Kaltdampf-Atomabsorptionsspektralphotometrie

Zusammenfassung Zur Vermeidung von systematischen Fehlern bei der Ultraspurenanalyse von Quecksilber im Meerwasser wurde ein integriertes Probenahme-Analysensystem entwickelt. Eine 500 ml PTFE-Flasche dient in Verbindung mit einem Greifarm als Probenahmegefäß für Oberflächenwasser und wird anschließend als Reaktionsgefäß in die Analysenapparatur gesetzt. Die Bestimmung erfolgt mit der Kaltdampf-Atomabsorptionsspektralphotometrie nach Reduktion des Quecksilbers durch SnCl₂ und Anreicherung sowie Reinigung mittels Amalgamierung an feinverteiltem Gold. Die Nachweisgrenze dieses Verfahrens beträgt 0,5 ng·l^–1, der Variationskoeffizient 4% bei 1,5 ng·l^–1.

     

Determination of wear metals in lubricating oils by flame atomic absorption spectrophotometry

A simple, rapid and reliable method was developed for the determination of copper, nickel, iron and lead in fresh and used lubricating oil samples by flame atomic absorption spectrophotometry (FAAS). In the present study, a mixture of organic solvents containing propionic acid and iso-butylmethyl ketone (1: 1) was used to extract the metals from lubricating oil samples followed by FAAS analysis. Aqueous standard solutions can be easily employed with the proposed mixed solvent system instead of organometallic standards. The analytical results obtained by employing the proposed solvent extraction system were found to be in good agreement with the results for aqueous media obtained after the destruction of oil samples matrix. Percentage recovery studies showed 88–98% for Cu, 92–95% for Fe, 96–106% for Ni and 84–100% for Pb with relative standard deviation of 2–6%. The developed method was effectively applied to routine determination of Cu, Ni, Fe, and Pb in lubricating oil samples.     

Determination of selenium in meat products by hydride generation atomic absorption spectrophotometry

Wet digestion using a mixture of nitric, sulfuric, and perchloric acids and an aluminum block digester effectively and rapidly decomposed meat samples for selenium determination by hydride generation atomic absorption spectrophotometry. Digestion did not require constant attention by an operator. Selenium recoveries (range, 94-105%) from National Institute of Standards and Technology standard reference materials and spiked samples were used to validate method accuracy. Coefficients of variation (CVs) of repeatability of in-house reference materials used for precision study were 6.4 and 5.6%, respectively, for seafood mix and mutton liver. Selenium levels in meat products from Brisbane markets varied widely: 0.042-0.142, 0.081-0.42, and 0.050-0.198 microgram/g (wet weight) respectively, for beef, chicken, and pork. Overall, selenium levels in manufactured meat ranged from 0.041 to 0.189 microgram/g. The levels of selenium found in this study were generally lower than those reported in Finland but comparable with those reported in some parts of the United States.     

Determination of some heavy metals in sea water by atomic absorption spectrophotometry

Summary Direct determination of trace metals in sea water by flame atomic absorption technique suffers from serious interferences caused by the high salt content. Separation of the metals from the matrix has been effected by chelation and extraction with ammonium pyrrolidine dithiocarbamate and methyl-isobutyl-ketone. Besides a separation preconcentration and increased sensitivity is achieved with this extraction. Organic substances and metal-organic complexes are destroyed with UV-radiation before extraction is carried out. Flameless atomic absorption has been tried using the Heated Graphite Furnace combined with a) a selective volatilization procedure, b) removing of sodium from the samples using hydrated antimon pentoxide (HAP). Both methods were used to remove the interfering substances (mainly sodium salt). All the techniques have been compared by analysing the same sea water samples, some of which were also analysed by other laboratories.

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Bestimmung einiger Schwermetalle in Meereswasser durch Atomabsorptions-Spektralphotometrie

Zusammenfassung Die direkte Bestimmung der Spurenmetalle in Meereswasser durch Flammen-Atomabsorption wird durch den hohen Salzgehalt behindert. Die Abtrennung der Metalle von der Matrix wurde durch Komplexierung und Extraktion mit Ammoniumpyrrolidindithiocarbamat und Methylisobutylketon erreicht, wodurch außerdem eine Anreicherung und Steigerung der Empfindlichkeit erzielt wird. Organische Substanzen und metallorganische Komplexe können durch UV-Bestrahlung vor der Extraktion zerstört werden. Die flammenlose Technik mit Hilfe des erhitzten Graphitrohres wurde in Kombination mit a) einer selektiven Verdampfungsmethode und b) der Entfernung des Natriums mit hydratisiertem Antimonpentoxid eingesetzt. Alle Verfahren wurden an Hand der gleichen Wasserproben verglichen. Tests wurden auch von anderen Laboratorien durchgeführt.

This work was made possible by substantial grants from International Atomic Energy Agencies (IAEA) and from the Royal Norwegian Council for Scientific and Industrial Research.     

Determination of lead and cadmium in milk by electrothermal atomic absorption spectrophotometry

The concentration of lead and cadmium in different kinds of milk samples (powdered, infant formula, market, buffalo, condensed and human) were determined using electrothermal atomic absorption spectrophotometric technique. Among all the varieties of milk analysed, condensed milk was found to contain much higher amount of lead. Human milk as expected was found to have lowest concentration of these elements. The results were compared with the reported values of other countries. Daily intake of these toxic elements by adults and babies up to the age of six months through the consumption of various types of milk was estimated and compared with the tolerance levels.     

Determination of copper and antimony in lead alloy by atomic absorption spectrophotometry

Summary A method has been proposed for the rapid determination of copper and antimony in lead alloy used for telephonic cable sheath. The sample is dissolved in a nitric acid solution and the determination is made by atomic absorption spectrophotometry. The calibration is simply effected with aqueous standard solutions, since no difference was detected between this calibration and the standard addition method.

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Zusammenfassung Ein Verfahren zur raschen Bestimmung von Kupfer und Antimon in der für Telefonkabelumhüllungen verwendeten Bleilegierung wurde angegeben. Die Probe wird in Salpetersäure gelöst und die Bestimmung durch tomabsorptions-Spektrometrie durchgeführt. Die Eichung erfolgt mit wäßrigen Standardlösungen, zumal gegenüber der Standardzusatzmethode keine Differenzen auftreten.

     

Determination of vanadium in human hair slurries by electrothermal atomic absorption spectrometry

This work describes an analytical procedure for vanadium determination in human hair slurries by electrothermal AAS using longitudinal heating (LHGA) and transversal heating (THGA) graphite furnace atomizers. The samples were powdered using cryogenic grinding and the hair slurries containing 0.2% (m/v) were prepared in three different media for determination of vanadium: 0.14 mol L⁻¹ HNO₃, 0.1% (v/v) Triton X-100 and 0.1% (v/v) water soluble tertiary amines (CFA-C, pH 8). The limits of detection (LOD), limits of quantification (LOQ), and characteristic masses obtained were 0.28, 0.95 μg L⁻¹ and 35 pg (LHGA) and 0.34, 1.13 μg L⁻¹ and 78 pg (THGA), respectively. The accuracy of the analytical results obtained by the proposed procedure in both equipments was confirmed by a paired t-test at the 95% confidence level and compared with a conventional procedure based on acid digestion.     

Blood lead by furnace-Zeeman atomic absorption spectrophotometry

A quick, accurate graphite furnace-atomic absorption spectrophotometric method for blood lead in the range 5 to 50 μg/dl was evolved by adding a 0.100-ml blood sample to 0.400 ml of aqueous 0.2% (w/v) Triton X-100, followed by the addition of 0.500 ml of Type I water. After shaking, a 10-μl aliquot was inserted into a pyrolytically coated graphite furnace tube in a Zeeman atomic absorption spectrophotometer. The method was validated by the method of standard additions, by mixing bloods of known lead content in known ratios, by two independent methods of isotope dilution/mass spectrometry, and by two independent methods involving anodic stripping voltammetry. Mixing bloods of known lead content in defined ratios is an acceptable substitute for the standard additions method.     

The determination of gold by atomic absorption spectrophotometry

Gold can be isolated from most other elements other than the platinum metals by the extraction of iron(II) 1,10-phenanthroline tetrabromoaurate in chloroform. After isolation gold can be determined in the organic solvent by atomic absorption spectroscopy or colorimetrically by decomposition of the complex and determination of the iron by bathophenanthroline.     

Determination of lithium in sea water by atomic absorption and by flame emission spectrophotometry

Summary Comparison of two instrumental methods for the analysis of lithium in sea water showed that both atomic absorption and flame emission spectrophotometry can be used without pretreatment of the sample. The interference of the other constituents of sea water in the analysis has been studied. Calibrations using an artificial sea water or the standard addition method may be used.

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Zusammenfassung Ein Vergleich der beiden Methoden hat gezeigt, daß zur Analyse von Lithium im Meerwasser sowohl die Atomabsorptionsspektrophotometrie, als auch die Flammenspektrophotometrie ohne Vorbehandlung der Probe angewendet werden können. Der Einfluß der anderen Bestandteile des Meerwassers auf die Analyse wurde untersucht. Für die Eichung des Verfahrens wurde künstliches Meerwasser sowie die Methode des Standardzusatzes verwendet.

     

The determination of selenium by atomic absorption spectrophotometry

The problems involved in the determination of selenium by atomic absorption spectrophotometry are discussed. A practical method is described for which the sensitivity is approximately 1 p.p.m. Such concentrations can be determined in organic samples, but with mineral samples the preliminary treatment renders the procedure unsuitable for concentrations lower than 50 p.p.m. in a sulphide ore.     

Determination of vanadium in mussels by electrothermal atomic absorption spectrometry without chemical modifiers

A method was developed for the quantitative determination of total vanadium concentration in mussels via electrothermal atomic absorption spectrometry (ETAAS). After the microwave digestion of the samples, a program using temperatures of 1600 °C and 2600 °C for ashing and atomization respectively, without any matrix modifiers, allowed us to obtain results that were satisfactory since they agreed closely with certified reference material values. The detection limit was 0.03 mg kg^–1 (dry weight), indicating that the method is suitable for the analysis of mussel samples. This determination was compared with matrix modifiers that have been reported previously. The method was applied to various cultivated and wild mussels from the Galician coast, yielding levels below 1 mg kg^–1 (wet weight).