Discussion of parameters associated with the determination of arsenic by electrothermal atomic absorption spectrometry in slurried environmental samples

A slurry sampling - fast program procedure has been developed for the deter mination of arsenic in plants, soils and sediments by electrothermal atomic absorption spectrometry. Efficiencies of various single and mixed modifier s for thermal stabilization of arsenic and for a better removal of the matr ix during pyrolysis step were compared. The influence of the slurry concent ration, amounts of modifier and parameters of the pyrolysis step on the As integrated absorbance signals have been studied and a comparison between fa st and conventional furnace programs was also made. The ultrasonic agitatio n of the slurry followed by a fast electrothermal program using an Ir/Mg mo difier provides the most consistent performance in terms of precision and a ccuracy. The reliability of the whole procedure has been compared with resu lts obtained after application of a wet digestion method with an HF step an d validated by analyzing eleven certified reference materials. Arsenic dete ction and quantitation limits expressed on dry sample matter were about 30 and 100 mug kg(-1), respectively.