Spectrophotometric Determination of Dibenzoylmethane by Diazocoupling Reaction in Pharmaceutical Preparations

A simple, sensitive, rapid and new specrophotometric method for the determination of Dibenzoylmethane (DBM) in aqueous solution was developed. The method was based on the coupling of DBM with diazotized p-nitroaniline in basic medium and in the presence of Triton X-100. The orange-red dye formed was water-soluble, stable and shows maximum absorption at 524 nm. Beer's law was obeyed over the range 5-500 µg/25ml, i.e., 0.2-20 ppm with a molar absorptivity of 3.04*104 l.mol-1 .cm-1 and Sandell's sensitivity index of 0.0074 µg.cm-2 , a relative error of -2.915 to 1.295 % and relative standard deviation of ±2.215 to ±3.848 %. The study of the interferences showed that the method was selective. The proposed method seemed effective and fast specrophotometric approach which has been applied successfully to determine DBM in some water samples, because there were no pharmaceutical preparations for the application of the method.