Spectral determination of para-aminophenols and meta-aminophenols in their mixtures using the tetra-cyanoethylene reagent In the aqueous solution

Abstract

A simple and selective spectrophotometric method is described for the
determination of p-aminophenol and m-aminophenol alone and in admixture. The
analysis is based on the reaction of tetracyanoethylene reagent with the above amines in
basic aqueous solution of sodium hydroxide forming two products having absorption
bands at λmax at 350 nm for p-aminophenol and at 466 and 350 nm for m-aminophenol.
Beer's law is obeyed in the range of 1-24 μg/ml for p-aminophenol at 350 nm and 2-34nm
for m-aminophenol at 466nm. The determination of amines in admixture is mainly
depended on the measurement of absorbances of complexes using two identical sets of
solutions, each at its λmax and under its respective optimised conditions. The accuracy
(average recovery %) are 99.66 % and 100.51 % for p-aminophenol and m-aminophenol
respectively with precision (RSD) less than 1.7 % for the two components in admixture.