Spectrophotometric Determination of Nitrazepam by Coupling of Diazotized Reduced Nitrazepam with N-(1-naphthyl)ethyl-enediamine Dihydrochloride


A simple, rapid, accurate and precise spectrophotometric method is proposed for the determination of nitrazepam in pure form. The method is based on the reduction of nitrazepam by zinc powder in concentrated hydrochloric acid medium followed by diazotization of reduced nitrazepam and coupling with N-(1-naphthyl)ethylenediamine dihydrochloride (NEDA) to give a pink coloured product which is stable, water-soluble and has a maximum absorption at 564 nm with a molar absorptivity of 1.633×103 l.mol-1.cm-1. Beer's law is obeyed in the concentration range of 10 to 500 μg of nitrazepam in a final volume of 25 ml.