Spectrophotometric determination of oxyphenbutazone by diazo coupling and subsequent chelation reactions

Abstract

Two spectrophotometric procedures for the assay of oxyphenbutazone have been developed, based on coupling with a diazo reagent, reaction with copper(II) and extraction of the resulting chelate into chloroform. The absorbance of the chelate was measured and its copper(II) content determined by treatment with diethyldithiocarbamate reagent. The stoicheiometric ratios of the stepwise reactions were assessed by the continuous variations method and the assay parameters leading to quantitative results investigated. The results obtained are compared with those obtained by an official method.