Determination of Trace Iron by Catalytic Kinetic Spectrophotometry with Potassium Bromate-o-Aminophenol System

In the medium of acetic-sodium acetate buffer solution (pH 2.5), Fe(Ⅲ) catalyzed the oxidation of o-aminophenol by potassium bromate and made coloration. Based on this fact, a method for determination of trace iron by spectrophotometry was established. The determination wavelength was 406 nm, the reaction temperature was 80℃, and the reaction time was 10 min. Linear relationship was found between the absorbance and the mass concentration of Fe(Ⅲ) in the range of 0.25-4.0 mg·L^-1, with detection limit (3s/k) of 0.011 mg·L^-1. The poposed method was used for the determination of trace iron content in industrial grade zinc sulfat, giving recovery rates obtained by standard addition method in the range of 102%-108% and RSDs (n=6) of 3.6%.