Simultaneous Spectrophotometric Determination of Paracetamol and p-Aminophenol by Using Mean Centering of Ratio Kinetic Profiles

A specific spectrophotometric method was developed for simultaneous determination of paracetamol (PCT) and p-aminophenol (PAP) in water samples without prior separation steps. The method is based on the mean centering of ratio kinetic profiles. Paracetamol and P-aminophenol react with Fe(III)/hexacyanoferrate(III) complex and result in the formation of colored complex, i.e. Prussian Blue. The differences in the rate of reaction of PCT and PAP with reagents make their simultaneous determination feasible by using mean centering of ratio kinetic profiles. The experimental parameters, such as reagent concentrations and pH were optimized for getting results with minimum errors. The analytical characteristics of the method such as detection limit, accuracy, precision, relative standard deviation (R.S.D.) and relative standard error (R.S.E.) for the simultaneous determination of binary mixtures of p-aminophenol and acetaminophen were calculated. The results show that the method was capable of simultaneous determination of 0.5-21.0 mu g mL(-1) and 0.1-15.0 mu g mL(-1) of PCT and PAP, respectively. The proposed method was successfully applied to the simultaneous determination of paracetamol and p-aminophenol in several pharmaceutical products and synthetics mixtures.