No abstract

Trace elements in fuel oils have been analysed by inductively coupled plasma mass spectrometry (ICP-MS) after acid solubilization of the samples in a microwave oven. The results relative to the National Institute of Standards and Technology SRM 16341, and SRM 1619 show good accuracy and precision for about 20 elements. The detection limits are, for most of the elements, in the range 0.02-0.2 pg g-'; values that are consistent with the concentrations of metallic impurities present in fuel oils. The good agreement obtained on real samples using neutron activation analysis is a demonstration that ICP-MS can compete with a well established reference technique for the determination of trace metals in fuel oil.

The method previously described by Casetta eta/. for the determination of aluminium in dilute (1 + 1) human serum using matrix modification and a stabilised temperature platform furnace has been considered. The combination of the platform, integrated absorbance, new coated tubes and oxygen addition to the charring step, provided better precision and smaller variation during the life of the tube. Good results were achieved by standardising the procedure against a calibration graph if integrated absorbance signals were used for quantitation. The calibration was linear up to at least 150 pg I-' of aluminium; the within-run and between-run precision was 5.5 and 6.5%, respectively (at 14.3 pg 1-1 of aluminium); and the recovery of aluminium added to pooled serum ranged between 97 and 102%. Furnace lifetimes in excess of 200-250 firings using oxygen ash i ng were routinely achieved.

Four decomposition procedures for coal fly ash samples were investigated for the subsequent determination of arsenic, cadmium, antimony, selenium, lead and thallium. Decomposition with nitric acid under pressure in a PTFE bomb or microwave oven was adequate for the determination of As and Se but resulted in low values for all the other elements. Decomposition with nitric, hydrofluoric and perchloric acids in a PTFE bomb could be utilised for As, Se, Cd, Pb and TI determinations whereas Sb was partly lost under these conditions. Decomposition with nitric, hydrofluoric and hydrochloric acids in a microwave oven was applicable for all the elements and gave results that were in good agreement with the certified values. The stabilised temperature platform furnace (STPF) technique with Zeeman-effect background correction was used for the determination of all the elements. After decomposition of the samples, calibration graphs were constructed using aqueous standards; use of standard additions was unnecessary for all the elements when using a Pd -Mg(NO& mixed modifier. The atomic absorption spectrometry (AAS) results for As, Sb and Se were compared with those obtained by neutron activation analysis (NAA). Keywords: Stabilised temperature platform furnace; Zeeman-effect background correction; coal fi y ash samples; sample decomposition procedure Paper 8100478A

No abstract