Spectrophotometric estimation of para-aminophenol via oxidative coupling reaction with 4-chlororesorcinol –Application to paracetamol

Abstract

A simple and sensitive spectrophotometric method has been suggested for the estimation of pure paminophenol(p-AMPL), and p-AMPL results from the hydrolysis of paracetamol (PARL). The suggested method is based on oxidative coupling reaction of p-AMPL with 4-chlororesorcinol and potassium periodate to produce a stable, and water-soluble colored product with maximum absorption at wavelength 556 nm. Beer's law is followed over the range of concentration from 2 to 20 μg. ml-1. The molar absorptivity value is equal to 1.0356×104 l.mol-1cm-1. All factors responsible for the completed reaction and highest intensity of the product have been studied, and the optimal of each factor has been selected. The suggested method was applied in an indirect method for the determination of paracetamol in tablets and injection after acidic hydrolysis to p-AMPL. The common excipients added did not interfere in the estimation of paracetamol.