Separation and determination of thiosulfate, sulfite and sulfide in mixtures

Abstract

The proposed method consists of three procedures: an excess of iodine for its reactions with both the thiosulfate separated in Procedure I and the sulfur dioxide evolved in Procedure II, and the thiocyanate formed from hydrogen sulfide in Procedure III are determined by spectrophotometry, respectively. Procedure I can be applied to the determination of up to 4.8 × 10^–4 mol l^–1 thiosulfate in the presence of sulfite and sulfide, Procedure II for up to 2.4 × 10^–4 mol l^–1 sulfite in the presence of thiosulfate and sulfide, and Procedure III for up to 6 × 10^–4 mol l^–1 sulfide in the presence of thiosulfate and sulfite. Good recoveries of thiosulfate, sulfite and sulfide added to hot-spring water and lake water samples were achieved by using the proposed method.