邻羧基苯基重氮氨基偶氮苯胶束水相分光光度测定痕量铊

Spectrophotometric determination of thallium with o carboxybenzenediazo aminoazobenzene by micellar solubilization

在乳化剂ＯＰ存在下，于１．１～３．０ｍｏｌ／Ｌ氨水介质中，铊（Ⅲ）与邻羧基苯基重氮氨基偶氮苯（ＣＤＡＡ）形成组成比为１２的稳定的橙红色配合物，其吸收峰波长在５１２ｎｍ，对比度Δλ＝９２ｎｍ，表观摩尔吸收系数为１．３４×１０５Ｌｍｏｌ－１ｃｍ－１，室温下显色反应立即完成，配合物至少稳定８ｈ，线性范围是０～０．８０μｇ／ｍＬ铊。方法用于水样、烟叶和煤灰中痕量铊的分析，回收率为９０．０％～１０１．４％，５次测定的相对标准偏差不大于４．６％。

A highly sensitive spectrophotometric procedure was investigated for the determination of trace thallium(Ⅲ) with o carboxybenzenediazo aminoazobenzene(CDAA) in the presence of p octylpolyethyleneglycol phenylether(OP) In ammonia medium of 1 1～3 0mol/L,the red complex developed has a maximum absorption at 512nm,with contrast Δλ=92nm,its apparent molar absorptivity is 1 34×10 5L·mol -1 ·cm -1 ,and the Sandell sensitivity is 1 53×10 -3 μg·cm -2 The development is complete immediately and the color is stable for at least 8h.The molar ratio of thallium(Ⅲ) to CDAA in the complex is found to be 1∶ 2 Beer′s law is obeyed in the concentration range of 0～0 80μg/mL for thallium.The proposed method has been applied to the determination of trace thallium in tobacco leaf,coal ash and tap water with a recovery of 90 0%～101 4% and a relative standard deviation( n =5) of less than 4 6%