4-(2-噻唑偶氮)连苯三酚分光光度法测定钢中微量钨

Sepectrophotometric determination of micro tungsten in steel sample with 4-(2-thiazolylazo)-1,2,3,-thrihydroxy-benzene

在稀硫酸介质及溴化十六烷基吡啶（CPB）存在下，试剂4-（2-噻唑偶氮）连苯三酚（TATB）与钨（Ⅵ）发生显色反应，据此建立了分光光度法测定钢样中微量钨的方法。研究发现：TATB与钨㈣形成2：1的红色络舍物，该络合物的最大吸收波长在530nm处。25mL溶液中，钨质量在0～40μg范围内服从比尔定律，测得表观摩尔吸光系数为6．16×10^4L·mol^-1·cm^-1。方法用于钢样中微量钨的测定，结果同硫氰酸盐光度法所得结果相吻合。

In dilute sulfuric acid medium, 4-（2-thiazolylazo）-1, 2, 3,-thrihydroxy_benzene （TATB） could react with tungsten （Ⅵ） in the presence of cetylpyridinium bromide （CBP）. On the basis of this reaction, a method of determining micro tungsten in steel sample by spectrophotometry was established. The results showed that TATB could form a red complex with tungsten （Ⅵ） with a reagent ： tungsten（Ⅵ） composition ratio of 2 ： 1. The maximal absorption peak of the complex was at 530 nm. Beer＇s law was obeyed for tungsten（Ⅵ） in the range of 0--40μg/25 mL. The apparent molar absorptivity was 6.16×10^4L·mol^-1·cm^-1. This method had been applied to the determination of micro tungsten in steel samples, and the results were consistent with those obtained by thiocyanate spectrophotometry.