在pH 2.5的乙酸-乙酸钠缓冲溶液的介质中，Fe （Ⅲ）催化溴酸钾氧化邻氨基酚显色，据此建立了测定微量铁的分光光度法。测定波长为406 nm，反应温度为80℃，反应时间为10 min。Fe （Ⅲ）质量浓度在0.25~4.0 mg·L^-1内与吸光度呈线性关系，检出限（3s/k）为0.011 mg·L^-1。方法用于测定工业硫酸锌中微量铁的含量，加标回收率在102%~108%之间，测定值的相对标准偏差（n=6）为3.6%。

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%.