Spectrophotometric Determination of p-Aminophenol Via Oxidative Coupling Reaction with N-(1-Naphthyl) ethylendiamine dihydrochloride in Presence of Potassium Iodate– Application to Paracetamol

Abstract

A simple, rapid and sensitive spectrophotometric method for the determination of paminophenol
is described. The method based on the oxidative coupling reaction of paminophenol
with N-(1-naphthyl) ethylendiamine (N-NED) using potassium iodate as
oxidizing agent in alkaline medium to form a water soluble product, that is stable and
has a maximum absorption at 520 nm. Beer’s law is obeyed in a concentration range
10 to 160 μg p-aminophenol / 25 ml with a molar absorptivity of 0.6002×104 L.mol-
1.cm-1, a relative error of –0.59 to +4.92% and a relative standard deviation of ± 0.89
to ± 4.49% depending on the concentration of p-aminophenol. The proposed method
has been successfully applied to the determination of paracetamol in various
pharmaceutical preparations after acidic hydrolysis to p-aminophenol.