建立了利用二硫代安替比林甲烷光度法测定铅冶炼废水中微量砷的分析方法。在1.8 mol·L^-1硫酸介质中，砷与二硫代安替比林甲烷显色剂发生灵敏的显色反应，最大吸收波长为331 nm。考察了显色剂用量、显色反应时间、介质、酸度、不同价态砷对测定结果的影响。结果表明：使用4 cm的比色皿，As³⁺的质量浓度在0.04~0.6 mg·L^-1内与其对应的吸光度之间呈线性关系，线性回归方程为y=1.063 x+0.001，相关系数为0.999 3，表观摩尔吸光系数为2.7×10⁴L·mol^-1·cm^-1。按照标准加入法进行回收试验，测得回收率为97.0%~105%，相对标准偏差（n=5）为1.3%~2.6%，该方法用于测定铅冶炼废水中微量砷的结果满意。

An analytical method for the determination of trace arsenic in lead smelting wastewater by spectrophotometric with disulfoantipymethane. In 1.8 mol·L^-1 H₂SO₄ medium, arsenic reacts with disulfoantipylmethanesensitively with an absorption maximum at 331 nm. The effects of reaction conditions, such as the amount of color reagent, reaction time, reaction medium, acidity and different valence arsenicon the absorbency were investigated. The results showed that linear relationship was found in the range of 0.04-0.6 mg·L^-1 As³⁺ in 10 mL solution using a 4 cm cuvette with the reagent blank as a reference, the linear regression equation was y=1.063 x+0.001, and the correlation coefficient was 0.999 3, the molar absorptivity was 2.7×10⁴L·mol^-1·cm^-1. Test for recovery was made by standard addition method, giving values of recovery in the range of 97.0%-105%, and values of RSDs (n=5) ranged from 1.3% to 2.6%. The proposed method was applied to the determination of trace arsenic in smelting wastewater with satisfactory result.