新显色剂4-甲基-2-磺酸基苯基重氮氨基偶氮苯的合成及与镉的显色反应研究

Synthesis of a New Chromogenic Reagent 4-Methyl-2-Sulfobenzenediazoam inoazobenzene (MSDAA) and Study on Its Color Reaction with Cadmium(Ⅱ)

报道了新显色剂４－甲基－２－磺酸基苯基重氮氨基偶氮苯的合成及其与Ｃｄ（Ⅱ） 的显色反应。实验表明，在非离子表面活性剂Ｔｒｉｔｏｎ Ｘ－１００存在下，于ｐＨ １０．８ 的氨水－氯化铵缓冲介质中，试剂与Ｃｄ（Ⅱ） 形成３∶１ 的红色络合物，最大吸收波长位于５２２ ｎｍ 处，Ｃｄ（Ⅱ） 含量在０～２０μｇ／２５ｍ Ｌ范围内符合比耳定律，表观摩尔吸光系数为２．０５ ×１０５ Ｌ·ｍ ｏｌ－ １·ｃｍ － １。已直接用于废水中微量镉的测定。

The method of synthesis of the new chromogenic reagent 4 methyl 2 sulfobenzenediazoaminoazobenzene and the conditions of its color reaction with cadmium(Ⅱ) have been investigated.It was found that the reagent reacted with cadmium(Ⅱ) to form a red complex with a molar ratio of 3∶1 in ammoniacal buffer solution(pH10 8) in the presence of nonionic surfactant Triton X 100 The maximum absorption of the complex is at 522nm and the apparent molar absorptivity is 2 05×10 5 L·mol -1 ·cm -1 .Beer's law is obeyed for 0～20μg of cadmium in 25 mL solution.This mothod has been employed to determine trace amount of cadmium(Ⅱ) in waste water with satisfactory results.