Determination of total inorganic arsenic in fish, shellfish and fish products

Abstract

Two methods are described for the determination of total inorganic arsenic in fish and fish products. The first method involves separation of the inorganic arsenic by distilling it from 6.6 N hydrochloric acid. The second method involves chelation and extraction of inorganic arsenic after sample dissolution in sodium hydroxide solution, with subsequent back-extraction and oxidation. In both methods the arsenic concentration is measured, after hydride generation by atomic-absorption spectrophotometry with atomisation in a flame-heated silica tube: with the first method the solution contains arsenic(III), and in the second the solution contains arsenic(V). Results obtained by both methods are in agreement over a range of samples. The distillation method is favoured for reasons of efficiency and economy in time. The derived limit of detection and confidence intervals are given.