Spectrophotometric determination of bismuth potassium ammonium citrate in cleaning wastes of industrial equipment with 4-(2’-pyridylazo)-resorcinol

Abstract

A simple spectrophotometric method for the determination of bismuth potassium ammonium citrate in the cleaning wastes of industrial equipment using 4-(2’-pyridylazo)-resorcinol is proposed. The method is based on displacement of bismuth from its potassium ammonium citrate by 4-(2’-pyridylazo)-resorcinol, formation of the colored complex, and the colorimetric determination of the resulting product. The calibration curve is linear within the range from 4 to 20 mg/L of bismuth potassium ammonium citrate, the molar attenuation coefficient is 10,100 m2/mol, the detection limit is 2.7 mg/L, the quantification limit is 8.2 mg/L. The method is selective with respect to the common excipients, exhibits a good accuracy (the relative uncertainty does not exceed 10%) and precision (the relative standard deviation does not exceed 5%), does not require lengthy sample preparation and sophisticated laboratory equipment and is suitable for the routine analysis of the cleaning wastes of industrial equipment.