2，6－二氯－4－硝基苯氨基重氮偶氮苯的合成及与镉（Ⅱ）显色反应的研究

STUDY ON THE SYNTHESIS OF 2,6-DICHLORO-4- NITRoBENZENEAMINODIAZOBENZENEAZOBEENZENE AND ITS COLOR REACTION WITH CADMIUM(Ⅱ)

本文合成了新试剂２，６－二氯－４－硝基苯氨基重复偶氮苯（ＤＣＮＡＤ）。研究了在吐温８０存在下ＤＣＮＡＤ与Ｃｕ（Ⅱ）的显色反应，结果表明在ｐＨ为１０．０～１０．８内ｃｕ（Ⅱ）与ＤＣＮＡＤ形成稳定的１：２配合钧，其最大吸收峰位于５９０ｎｍ，摩尔吸光系数为１．９×１０￣５１．ｍｏｌ￣（－１）．ｃｍ￣（－１），Ｃｄ（Ⅱ）的量在０～０．９μｇ／ｍｌ内符合比耳定律。以氟化钠－酒石酸钾钠－硫脲为掩蔽剂，方法具有较高的选择性，用于水样中微量镉的测定，获得了较好的结果。

A new reagent 2 , 6-dichloro-4-nitrobenzeneaminodiazobenzeneazobenzene(DCNAD)is synthesized. In the presence of Tween-80,DCNAD reacts with Cd(Ⅱ)to form a stable 1:2complex within pH 1 0.0～10.8 which exhibits a maximum absorption at 520nm with a molar ab-sorptivity of 1.9×10￣5 1.mol￣(-1)·cm￣(-1),Beer’s law is obeyed for 0～0.9μg/ml of Cd￣(2+) in 10 mlsolution. Interference of common foreign ions can be eliminated by a mixture of fluoride-tartarate-thiourea. This method is sensitive and selective,and applied to the determination of traces of Cd￣(2+)in water samples with satisfactory results.