文献曾报导5—(5—溴—2—偶氮吡啶)2—乙胺基对甲酚与In的显色反应,在此基础上本文研究了5—Br—PADAP与In的适宜反应条件,实验表明;pH3.9～5.6,In与5—Br—PADAP生成可溶于乙醇的橙红色络合物,最大吸收波长为565nm,摩尔吸光系数为7.18×10~4。由于5—Br—PADAP与许多金属离子都有极灵敏的显色反应,因此,该类试剂选择性较差,本文采用巯基棉富集分离In,可消除许多元素的干扰。该法应用于湿法炼锌试样—锌氧粉及中和渣中In的测定,结果较为满意。 The literature has reported the color reaction of 5- (5-bromo-2-azopyridine) 2-ethylamino p-cresol with In. On the basis of this, the suitable reaction conditions of 5-Br- The experimental results show that the maximal absorption wavelength is 565nm and the molar absorptivity is 7.18 × 10 ~ 4 when pH is 3.9 ~ 5.6, In and 5-Br-PADAP are soluble in ethanol. Since 5-Br-PADAP has a very sensitive color reaction with many metal ions, the selectivity of this reagent is poor. In this paper, In is used to enrich and separate In with thiol cotton, which can eliminate the interference of many elements. The method is applied to the determination of In in zinc hydrometallurgy and zinc hydrometallurgy, and the results are satisfactory.