Study on spectrophotometric determination of trace amount of bromate by oxidative decoloration of toluidine blue

A new color-fading spectrophotometric method for determining trace amount of bromate was developed.It was based on the oxidation of toluidine blue by potassium bromate in a dilute acidic solution containing 6 mol/L of HCl.This method was implemented at the room temperature.The optimum experimental conditions for the determination were found.The detection limit for bromate was 3.62×10-4 g/L,and the linear range of the determination was 0.1～0.9 μg/mL with the absorbance measured at 625 nm.The method was applied to the determination of trace amount of bromate in chemical reagents with satisfactory results.