OXIDATION OF THE ANALYTICAL REAGENT "TIRON" (DISODIUM-4,5-DIHYDROXYBENZENE-1,3-DISULPHONATE)

Abstract

The analytical reagent "tiron" undergoes oxidation in alkaline solution by the oxygen of the atmosphere to a yellow-colored substance, which is assumed to be the corresponding quinone. In certain circumstances the reagent may be oxidized with production of a green substance believed to be a semiquinone. Interference in the colorimetric determination of iron by means of this reagent may occur in alkaline solution owing to the overlap of the iron III derivative and of the oxidation product. Alkaline solutions of tiron react with iron II salts even in the rigorous absence of oxygen to form the iron III tironate FeR3−9. Oxygenated solutions of tiron in alkali fail to produce this compound with iron III salts, but do so with iron II salts.