Simple Method for Spectrophotometric Determination of Benzidine in Aqueous Solutions by Coupling with Β-Naphthol

Anew simple and rapid colorimetric method has been developed for the determination of benzidine in aqueous solutions. The method is based on the formation of a pink colored azo dye by diazotization of benzidine, followed by a diazo-coupling reaction between the resulting product and β-naphthol. The maximum absorbance of azo dye at 525 nm. Beer s law was found to be obeyed in the concentration range of 0-12 μg. ml1 with molar absorptivity 12360 L. mol1. cm1. The optimum reaction conditions and other analytical parameters were evaluated