Furnace AAS

The main advantages of electrothermal atomisers are that (a) very small samples (as low as 0.5 pL) can be analysed (b) often very little or no sample preparation is needed, in fact certain solid samples can be analysed without prior dissolution (c) there is enhanced sensitivity, particularly with elements with a short-wavelength resonance line in practice there is an improvement of between 102- and 103-fold in the detection limits for furnace AAS compared with flame AAS. [Pg.788]

Background effects especially due to the generation of particulate material to form a smoke are a major problem in furnace AAS. [Pg.794]

It should be stressed that background correction methods should always be used in furnace AAS. The background effect in this case may be as high as 85 per cent of the total absorption signal. [Pg.794]

Separation and detection methods The common methods used to separate the Cr(III)/(VI) species are solvent extraction, chromatography and coprecipitation. In case of Cr(VI) from welding fumes trapped on a filter, a suitable leaching of the Cr(VI) from the sample matrix is needed, without reducing the Cr(VI) species. The most used detection methods for chromium are graphite furnace AAS, chemiluminescence, electrochemical methods, ICP-MS, thermal ionization isotope dilution mass spectrometry and spectrophotometry (Vercoutere and Cornelis 1995)- The separation of the two species is the most delicate part of the procedure. [Pg.79]

The palladium and magnesium nitrates modifier has a substantial equalising effect on the atomisation temperature of the nine elements investigated. The optimum atomisation temperature for all but one element (thallium) is between 1900 and 2100 °C. This means that all elements can be determined at a compromise atomisation temperature of 2100 °C with a minimum sacrifice in sensitivity. Such uniform conditions for as many elements as possible are of vital importance if simultaneous multielement furnace techniques are envisaged. Moreover, in conventional graphite furnace AAS, uniform conditions for a number of elements can greatly facilitate and simplify daily routine analysis. [Pg.247]

Hodge et al. [689] have described a method for the determination of platinum and iridium at picogram levels in marine samples, based upon an isolation of anionic forms of these elements using appropriate resins, with subsequent purification by uptake on a single ion-exchange bead. All steps are followed by radiotracers, and yields vary between 35 and 90%. Graphite furnace AAS was employed as the determinative step. [Pg.247]

Maximum power heating, the L vov platform, gas stop, the smallest possible temperature step between thermal pretreatment and atomisation, peak area integration, and matrix modification have been applied in order to eliminate or at least reduce interferences in graphite furnace AAS. With Zeeman effect background correction, much better correction is achieved, making method development and trace metal determinations in samples containing high salt concentrations much simpler or even possible at all. [Pg.250]

Figure 5.20. a Chromatogram of stibine, methylstibine, and dimethylstibine as separated by the OV-3 trap/column with the quartz furnace/AA detector. The stibines were prepared by the NaBH4 reduction of 2 ng Sb each as Sb (III), methylstibonic, and dimethylstibonic acid, b Analysis of a sample of seawater (100 ml) from the open Gulf of Mexico (Station SN4-3-1, 12 March 1981)... [Pg.255]

Nakashima et al. [719] detail a procedure for preliminary concentration of 16 elements from coastal waters and deep seawater, based on their reductive precipitation by sodium tetrahydroborate, prior to determination by graphite-furnace AAS. Results obtained on two reference materials are tabulated. This was a simple, rapid, and accurate technique for determination of a wide range of trace elements, including hydride-forming elements such as arsenic, selenium, tin, bismuth, antimony, and tellurium. The advantages of this procedure over other methods are indicated. [Pg.256]

The relative advantages and disadvantages ofvoltammetric and atomic absorption methodologies are listed below. It is concluded that for laboratories concerned with aquatic chemistry of metals (which includes seawater analysis), instrumentation for both AAS (including potentialities for graphite furnace AAS as well as hydride and cold vapour techniques) and voltammetry should be available. This offers a much better basis for a problem-orientated application of both methods, and provides the important potentiality to compare the data obtained by one method with that obtained in an independent manner by the other, an approach that is now common for the establishment of accuracy in high-quality trace analysis. [Pg.265]

Donat and Bruland [804] studied the speciation of copper and nickel in seawater by competitive ligand equilibration-cathodic stripping voltammetry, differential pulse ASV, and graphite furnace AAS. [Pg.276]

Abollino et al. [690] compared cathodic stripping voltammetry and graphite furnace AAS in determination of cadmium, copper, iron, manganese, nickel, and zinc in seawater. The effects of UV irradiation, acidification, and online sample preconcentration were studied. [Pg.277]

Antimony Sb(III) and Sb(VI) adsorbed as ammonium pyrrolidine dithiocarbamate complexes onto Cis bonded silica Graphite furnace AAS 0.05 [xg/1 [860]... [Pg.291]

Barium Barium pre-concentrated on cation exchange resin, then extraction with nitric acid Graphite furnace AAS [78]... [Pg.291]

Beryllium Beryllium pre-concentrated as acetylacetone complex onto activated charcoal Charcoal introduced directly into graphite furnace AAS 0.6 ng/1 0.0006 xg/l [79]... [Pg.291]

Cadmium Cadmium collected on Chelex-100 resin and elution with Graphite furnace AAS nitric acid [118]... [Pg.291]

Cobalt Complexation with 4-(2-thiazolylazo) resorcinol, adsorption on XAD-4, resin elution with methanohchloroform Graphite furnace AAS - [234]... [Pg.292]

Lead Complexation with ammonium pyrrolidine dithiocarba-mate, collection on C18 microcolumn Graphite furnace AAS 3.5 ng/1 [873]... [Pg.294]

Manganese Extraction with chloroformic 8-quinolol, back extraction Graphite furnace AAS < 30 ng/1 [432,444]... [Pg.294]

Molybdenum Anion exchange resin adsorption (Biorad Agl-X8), elution Graphite furnace AAS <10p,g/l... [Pg.295]

Selenium Selenium(IV) ammonium pyrrolidine diethyldithiocarba-mate complex adsorbed onto Cis bonded silica, then desorbed Graphite furnace AAS 7 ng/1 [860]... [Pg.297]

Selenium Conversion of selenium into selenium hydride Selenium hydride swept into quartz tube at 400 °C, analysed by hydride generation Graphite furnace AAS 20 ng/1 [906]... [Pg.297]

Zinc Zinc collected on methyl capryl ammonium chloride coated Cis resin Graphite furnace AAS 2.4 xg/l [617]... [Pg.299]

Zinc Zinc adsorbed on Chelex-100 resin, desorbed with nitric acid Graphite furnace AAS 0.5 [Xg/l [618]... [Pg.299]

Table 5.13. Pre-concentration of metals in sea water chelation-solvent extraction techniques followed by direct AAS and graphite furnace AAS... [Pg.300]

Grobenski Z, Lehmann R, Radzuck B, Voellkopf U (1984) The determination of trace metals in seawater using Zeeman graphite furnace AAS. In Atomic Spectroscopy Application Study No. 686 (1984) Papers presented at Pittsburgh Conference, Atlantic City, NJ, USA... [Pg.322]

Analytical Methods for Graphite Furnace AAS (1984) Perkin-Elmer... [Pg.322]

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