Kinetic Spectrophotometric Method for Trace Amounts Determination of Bromide in Pharmaceutical Samples Using Janus Green-Bromate System

A new simple and rapid kinetic spectrophotometric method has been developed to trace amounts determination of bromide. This method is based on the catalytic effect of bromide on the reaction between Janus Green and bromate in sulfuric acid media. The reaction was followed spectrophotometrically by measuring the absorbance at 618 nm. The fixed-time method was used for the first 210 s. The influence of reagents concentration, temperature and time on the sensitivity was studied. Under optimum experimental conditions, bromide can be determined in the range of 10.0-1800.0 ?g/L. The relative standard deviations (n = 10) were 0.22 and 0.19% for 100.0 and 1000.0 ?g/L of bromide, respectively. The detection limit of the proposed method was 4.1 ?g/L. The influence of potential interfering of some ions and biological species on the selectivity was studied. The proposed method was successfully applied for the determination of bromide in pharmaceutical samples. The new developed method was found to have fairly good selectivity, sensitivity, simplicity and rapidity.