分光光度法测定降水中微量过氧化氢

Determination of Trace Hydrogen Peroxide in Rain Water with Spectrophotometric Method

研究了一种测定降水中微量过氧化氢的方法。在0.4～1.5mol／L磷酸介质中，过氧化氢与钒（V）及2－（3，5-二溴-2-吡啶偶氮）－5-二乙氨基苯酚（3,5-diBr-PADAP）反应形成一种组成比为1：1：1的蓝色三元配合物，其最大吸收波长为598nm，表现摩尔吸光系数为5.6×104L·mol-1·cm-1。过氧化氮量在2×10-7～1．3×10－5mol／L时服从比耳定律。方法简便，选择性较高，用于降水中微量过氧化氢的直接测定，结果令人满意。

A spectrophotometric method for the determination of trace amount of hydrogen peroxide inrain water has been studied. In the medium of 0. 4~ 1. 5 mol/L phosphoric acid, hydrogen perox-ide reacts with vanadium (V) and 2- (3, 5-dibrome-2-pyridylazo) -5-diethylaminophenol (3, 5-diBr-PADAP) to form a 1: 1: 1 blue ternary complex. lts maximum absorption is at 598 nm, andthe apparent molar absorptivity is 56000 L mol-1- cm -1. Beer's law is obeyed over the range of 2×10-7~1. 3 × 10-5 mol/L for hydrogen peroxide. The method is simple and good selective, andhas been applied to the direct determination of hydrogen peroxide in rain water with satisfactoryresul ts.