Selective Determination of Inorganic Arsenic (III), (V) and Organic Arsenic in Biological Materials by Solvent Extraction-Atomic Absorption Spectrophotometry

Abstract

A new method for the selective determination of inorganic arsenic (III), (V) and organic arsenic has been performed. Each chemical form of arsenic in biological materials was solubilized in 6 n hydrochloric acid. Inorganic arsenic (III) was extracted into toluene from 9 N hydrochloric acid solution, and inorganic arsenic (V) was also extracted after reduction by potassium iodide. Organic arsenic was retained in hydrochloric acid solution. After arsenic in toluene solution was back-extracted into water, aqueous or hydrochloric acid solution containing arsenic was wet digested with a mixture of HNO3, H2SO4 and HClO4, and arsenic was determined by atomic absorption spectrophotometry. The proposed method was applied to some kinds of algaes, shark muscle and orchard leaves (NBS SRM 1571). 90~100% of arsenic in algaes (Wakame, Arame, Kazime) and shark muscle was organic, while all the arsenic in orchard leaves was inorganic. © 1978, Japan Society for Bioscience, Biotechnology, and Agrochemistry. All rights reserved.