应用V-H_2O_2-TADAP三元配合物光度法测定钒

Spectrophotometric Determination of Vanadium with 2-(2 Thienylazo) -5-Diethylaminophenol and Hydrogen Peroxide

在pH5.6～6.0时钒(V)与2-(2-噻吩偶氮)-5-二乙氨基酚(TADAP)形成λmax位于590nm的红色配合物。当加入过氧化氢时则形成组成为1:1:1的三元配合物,反应pH值向酸性方向移动,适宜的pH值为1.10～1.50,λmax移至600nm,显色反应具有较高的灵敏度(ε=5.1×10_4L·mol^(-1)·cm^(-1)和良好的选择性,方法可用于钢铁和其他样品中钒的直接分光光度测定。

In the pH 5.6-6.0, vanadium (V) reacts with 2-(2-Thienylazo)-5-diethylaminophenol (TADAP) to form a red complex of max at 590 nm. When added H2O2, vanadium (V) forms a ternary complex with TADAP and H2O2 in the molar ratio of 1 :1 : 1. The pH of the reaction shifts to acid side and the optimum range of pH is between 1.10 and 1.50, and Amax shifts to 600 nm. The colour reaction has higher sensitivity ( e = 5.1x105L mol-1 cm-1. ) and good selectivity. The method can be applied for direct spectrophotometric determination of vanadium in iron, steel and some othersamples.