DMTAA与钴(Ⅱ)新显色反应的研究

THE COLOUR REACTION OF COBLAT WITH DMTAA

本文对新试剂DMTAA与钴(Ⅱ)的显色反应进行了系统研究。结果表明,在pH6.8～8.0范围内,DMTAA与钴(Ⅱ)形成2∶1的隐定紫红色配台物,加入适量强酸,可使其转化为青篮色配合物,对比度和灵敏度提高。在0.9～3.5mol.L^(-1)HCIO_4溶液中,配合的最大吸收波长位于644nm,表观摩尔吸光系数为1.05×10~5 L·mol^(-1)·cm^(-1)。钴含量在0～12μg/25ml 范围内,吸光度遵守比尔定律。应用本法对几种合成样品中微量钴的测定,结果满意。

A Sensitive spectrophotometric method for the determination of Co is based on the reaction of Co with DMTAA to form a complex which is stable in a medium 0.9—3.5 mol/l HClO_4,0.7—2.5mol/l HCl,0.7—3.0 mol/l H_2SO4 and 0.6—2.8 mol/l H_3PO_4.Its molar absorptivity is 1.05×10~5 at 644nm.The molar ration of Co to DMTAA is 1:2.Beer's law is obeyed for 0—12 ug/25 ml of Co.The method has been appllied to the determination of Co in artificial Samples which contained known amounts of Co with satisfactory results.