Abstract
The conditions under which each species of thiosulfate, sulfite and sulfide can be selectively separated from their mixtures have been established. The proposed method comprises three procedures: excess iodine for its reaction with the thiosulfate separated in Procedure I and the thiosulfate formed from sulfur dioxide in Procedure II; the thiocyanate formed from hydrogen sulfide in Procedure III is spectrophotometrically measured. The sulfur dioxide separated from a mixture of thiosulfate and sulfide was introduced into a solution containing a buffer and sulfur; the sulfur dioxide was completely converted into thiosulfate. Procedure I can be applied to the determination of up to 4.8×10-4M thiosulfate in the presence of sulfite and sulfide, Procedure II up to 4.8×10-4M sulfite in the presence of thiosulfate and sulfide, and Procedure III up to 6×10-4M sulfide in the presence of thiosulfate and sulfite. Good recoveries of thiosulfate, sulfite and sulfide from hot-spring and lake-water samples were achieved using the proposed method.
