Spectrophotometric Determination of Chromium in Steel by Extraction of its Ion Association Complex with Tetraphenylarsonium Chloride

Department of Chemistry, University of Gauhati, Ganhati-781 014, Assam

Manuscript received 15 April 1981, accepted 10 December 1981

Chromium(VI) forms ion association complex with tetraphenylarsonium chloride extractable into chloroform and 1,2-dichloroethane. Based on the ultraviolet absorption of this ion pair in 1,2-dlchloroethane, the better extractant of the two, a method of the determination of chromium was evolved. Interfering effect of a number of ions where investigated. The relative ease of conversion of chromium(III) to chromium(VI) alfords a means of its separation from most of the commonly associated elements. Methods have also been developed to remove the interference due to a few anions that are extractable with tetraphenylarsonium chloride into 1,2-dichloroethane. The method was subsequently used in the determination of chromium in standard steel samples.