The Chemical Behavior of Low Valence Sulfur Compounds. IX. Photometric Determination of Thiosulfate, Trithionate and Tetrathionate in Mixture

Abstract The cyanolysis and photometric determination of thiosulfate, trithionate and tetrathionate have been investigated under the various conditions. The cyanolysis of thiosulfate catalyzed by cupric ions proceeded quantitatively in the presence of acetate buffer solution of pH 4.5, while the degree of cyanolysis of trithionate and that of tetrathionate were 0.3 and 0.6%, respectively. The degree of cyanolysis of trithionate was not so depressed as to a negligible extent by the methods previously proposed, but was depressed to 0.7% or less by the addition of such organic solvents as acetone, methanol, etc. The determination of thiosulfate, trithionate and tetrathionate in the concomitant presence of them could be made with a high accuracy.