Kinetic spectrophotometric determination of nitrite by catalytic oxidation of bromocresol green with potassium bromate

A new catalytic spectrophotometric method for determination of nitrite was developed,which was based on the catalytic effect of trace nitrite on the oxidation of bromocresol green by potassium bromate in a slightly acidic solution of 1.5 mol/L H3PO4.This method was operated in the room temperature without disturbance from many ions.The optimum experiment condition for the determination was identified.Kinetic parameters were studied.The detection limit for nitrite was 1.2×10-9 g/mL,and the linear range of the determination was 0.004～0.32 mg/L with the absorbance measured at 443 nm.The method was sensitive and selective.It was applied to the determination of trace nitrite in water sample with satisfactory results.