新试剂二甲基苯基重氮氨基偶氮苯与镉的显色反应研究及其应用

The colour reaction of cadmium with new reagent dimethylphenyldiazoaminoazobenzene and its application

研究了新试剂二甲基苯基重氮氨基偶氯苯（ＤＭＰＤＡＢ）的一些性质以及它与镉的显色反应。在ＴｒｉｔｏｎＸ－１００存在下，ｐＨ为８．５～１０时，镉与试剂形成桔红色１：２型配合物。最大吸收位于５２４ｎｍ，摩尔吸光系数为１．９×１０５Ｌ·ｍｏｌ－１·ｃｍ－１，Ｃｄ（Ⅱ）在０～２０μｇ／２５ｍＬ符合比耳定律。直接测定了天然水中的镉，标准加入回收率％～１０３％，相对标准偏差为１．５％。

In this paper ,the colour reaction of the new reagent dimethylphenyldiazoaminoazobenzene(DMPDAB) with cadmium was studied. In the presence ofTriton X-100, the reagent forms with Cd(Ⅱ) areddish orange complex,the molar ratio of Cd(Ⅱ)to DMPDAB is 1:2. The molar absorptivity is 1.91×105 L·mol-1 ·cm-1 at 524um and at pH 8.5～10.Beer′s law is obeyed for Cd(Ⅱ)in the range of 0～20μg/25mL .The proposed method was applied tothe direct determination of trace cadmium(Ⅱ) innatural waters.The relative standard deviation is1.5% and the recovery is 99%～103%.