ERIOCHROME BLACK T - A NEW ANALYTICAL REAGENT FOR SPECTROPHOTOMETRIC DETERMINATION OF SULPHANILAMIDES

Optimal conditions of the sulphanilamides diazonium salts interaction with o, o'-dihydroxysubstituted azo dye eriochrom black T have been defined. Therefrom the method of spectrophotometric determination of ten sulphanilamides in finished medicinal forms has been developed. This method is based on the azocoupling reaction of the sulphanilamide diazo salt with one of the products of the redox destruction of azo dye with formation of a colored azo compound. This method is characterized by the wide linearity range (from 3 to 64 mu g/ml depending on the detectable sulphanilamide), simplicity, rapidity (duration of analysis is under 30 min), and reproducibility (S-r similar to 0.040).