APPLICATION OF THE IODINE-AZIDE REACTION TO THE CATALYTIC DETERMINATION OF DIVALENT SULFUR-COMPOUNDS IN ALCOHOLIC MEDIUM - DETERMINATION OFETHYLENETHIOUREA IN SOME BIOLOGICAL-MATERIALS

A new catalytic method for the determination of divalent sulphur compo unds, which are soluble or insoluble in water, based on the iodine-azi de reaction in various alcoholic solutions is described. As model diva lent sulphur catalysts the sodium sulphide and thiourea were chosen. D etermination of ethylenethiourea in alcoholic extracts from apples and bananas was an example of practical application of the proposed metho d. To that purpose five previous elaborated techniques were adopted: t itration, volumetric, gas chromatographic, enthalpimetric and potentio metric. The effect of other organic solvents, salts, acids and pH on t he determination of divalent sulphur catalysts was also evaluated.