SYNTHESIS AND STUDIES ON THE ANALYTICAL FUNCTIONS OF A HIGHLY SELECTIVE SPECTROPHOTOMETRIC REAGENT 2-(8-QUINOLYLAZO)-5-N,N'-DIMETHYLAMINOBENZOIC ACID

A new highly-selective chromogenic reagent, 2-(8-quinolylazo)-5-N,N'-d imethylaminobenzoic acid (QAMB) has been synthesized. In pH 4.0-8.0 me dium, the reagent reacts only with cobalt or copper ions to form blue- green complexes, In alkaline medium, the reagent also reacts with nick el, mercury and palladium ions to form blue complexes, Therefore, QAMB may be the most selective among heterocyclic azo-chromogenic reagents , The physical acid chemical properties of QAMB and its colour-formati on reaction with cobalt ions have been studied in detail. A new spectr ophotometric method for the determination of cobalt in iron and steel samples has been developed.