A RAPID CHROMATOGRAPHIC METHOD FOR THE DETERMINATION OF MINUTE QUANTITIES OF TELLURIUM IN THE PRESENCE OF LARGE AMOUNTS OF BISMUTH

摘要

A rapid chromatographic method has been developed for the determination of minute quantities of Te in the presence of Bi in a hydrochloric acid medium.nThe present method is based on a selective separation of Te from Bi by ascending paper chromatography, using a solvent mixture of isopropyl ether and ethanol acidified with HC1. Under these conditions, Bi and Te have differ¬ent Rf values.nWhen the chromatogram is sprayed with an acidified solution of SnCl2, only one dark spot is obtained. This spot corresponds to metallic Te, resulting from its reduction to the elementary state,nThe intensity of the colour and the area of the spot are proportional to the quantity of Te present, since Bi is not reduced under acidic conditions. The spot of Bi may be detected by spraying the paper with an alkaline solution of SnCl2 using PbCl2 as a catalyst.