采用Fe²⁺-邻苯二胺（OPD）显色光度法测定了过氧乙酸（PAA）消毒液中的PAA含量。取0.25 mL消毒液，用0.01 mol·L^-1高锰酸钾溶液滴定至溶液呈稳定的浅粉色。分取5.00 mL样品溶液，依次加入10 g·L^-1 OPD溶液、乙酸-乙酸钠缓冲溶液（pH 1.5）和0.01 mol·L^-1 Fe²⁺溶液，室温下反应3 min，于448 nm处测定其中的PAA含量。结果表明：Fe²⁺可有效降低OPD与PAA显色反应的表观活化能，显色反应在3 min内即可完成，反应体系的摩尔吸光系数为5.8×10³L·mol^-1·cm^-1。PAA的浓度在0.24 mmol·L^-1以内与其对应的吸光度呈线性关系，检出限（3s/k）为5.0×10^-3mmol·L^-1。方法用于PAA消毒液中PAA含量的测定，测定值与标示值一致，测定值的相对标准偏差（n=6）小于2.2%。以PAA消毒液为基质进行加标回收试验，得到回收率为97.5%~105%。

The content of peracetic acid (PAA) in disinfectant of PAA was determined by spectrophotometry with Fe²⁺-o-phenylenediamine (OPD) as chromogenic reagent. 0.25 mL of disinfectant solution was titrated to a stable pink with 0.01 mol·L^-1 potassium permanganate solution. An aliquot (5.00 mL) of sample solution was mixed with 10 g·L^-1 OPD solution, acetic acid-sodium acetate buffer solution (pH 1.5) and 0.01 mol·L^-1 Fe²⁺ solution in sequence. After reacting for 3 min at room temperature, the content of PAA was determined at 448 nm. The results showed that the apparent activation energy of the color reaction between OPD and PAA was reduced effectively by using Fe²⁺ as catalyst, and the color reaction could be completed within 3 min, with the molar absorption coefficient of the reaction system of 5.8×10³L·mol^-1·cm^-1; a linearity relationship between concentration of PAA and its respective absorbance was kept within 0.24 mmol·L^-1, with detection limit (3s/k) of 5.0×10^-3mmol·L^-1. The method was used for the determination of PAA content in disinfectant of PAA, and determined values were consistent with labeled values, with RSDs of the measured values (n=6) less than 2.2%. Recovery test was made by standard addition method using PAA disinfectant as matrix, giving recoveries in the range of 97.5%-105%.