Spectrophotometric Determination of Paracetamol Using Diazotization Coupling Reaction

Abstract

An accurate, simple, and sensitive indirect spectrophotometric method which proposed and developed for the determination of paracetamol in different pharmaceutical preparations. The proposed method was based on acid hydrolysis of PAR to produced p-aminophenol (PAP), PAP was diazotization with nitrite ion to form the corresponding diazonium salt, followed by coupling with histidine reagent in alkaline medium to produced azo dye that showed maximum absorbance at 430 nm. Beer's law was obeyed in the concentration rage of 10-500 µg/20 ml (i.e. 0.5-25 ppm). The molar absorpitivity and Sandell's sensitivity of the dye were. 1.118×104 l.mol-1.cm-1and 0.0135 µg.cm-2 respectively. The method successfully has been applied for the determination of PAR in pure form,and its pharmaceutical preparations (tablets, syrup and injection). Keywords: Paracetamol, Indirect Spectrophotometric, Histidine, P-aminophenol.