Determination of arsenic in an organic phase by coupling continuous flow extraction-hydride generation with inductively coupled plasma atomic emission spectrometry

Abstract

Based on the generation of arsine from an organic phase, as an alternative method of sample introduction, a sensitive and selective analytical method for the determination of As by inductively coupled plasma (ICP) atomic emission spectrometry (AES) has been developed. Arsenic is first extracted into xylene, as Asl₃, using 0.1 M Kl in 7.5 M HCl, this solution is then mixed, on line, with NaBH₄ in dimethylformamide solution and acetic acid. A laboratory-built gas-liquid continuous separation device prevented most of the organic phase vapour from entering the plasma. Optimum conditions for the extraction and final ICP-AES determination of As were established. A detailed interference study is given showing the usefulness of extraction in combination with hydride generation. Using the proposed procedure, As was determined in white metal, cast iron, cupro-nickel and biological (orchard leaves) standard reference materials and very good agreement between our results and the certified values was obtained.