Optimization of sample preparation conditions in the determination of total arsenic in fish and seafoods by atomic absorption spectrometry with electrothermal atomization

Abstract

The conditions for sample preparation and determination of total arsenic in fish and seafoods by atomic absorption spectroscopy with electrothermal atomization have been optimized. When using a standard sample preparation procedure (GOST R 53100), a complete decomposition of the organic arsenic compound, arsenobetaine, appeared impossible which leads to underestimated results. A novel sample preparation procedure for the determination of total arsenic, including the addition of concentrated sulfuric acid for complete decomposition of the organic forms of arsenic to inorganic ones is proposed. During the atomization of the sample, an additional stage of drying was introduced with smooth heating from 200 to 250°C, which contributed to a complete removal of sulfuric acid residues from the injected sample volume. The correctness of the proposed methodology was verified using the ICP-MS method and in the analysis of reference samples of fish and seafoods.