新显色剂二溴硝基苯基重氮氨基偶氮苯的合成及与镉的显色反应的研究

Synthesis of 2 , 6-Dibromo-4-nitrobenzenediazoaminoazo-benzene and Its Color Reaction With Cadmium

作者合成了新显色剂2,6-二溴-4-硝基苯基重氮氨基偶氮苯(DBNDAA)。在pH8.5的硼砂-盐酸缓冲介质中,在Tween 80-SDBS存在下,该试剂与镉(Ⅱ)生成络合比为3:1的红色络合物,λ_(max)=500nm,ε_(500)=1.52×10~5L·mol^(-1)·cm^(-1)。镉量在0～28μg/25ml范围内遵守比耳定律。并测定了试剂的表观离解常数和络合物的表观不稳定常数。方法有良好的选择性。用该试剂测定了铝合金标样、环境水样及废水中的痕量镉,结果满意。

The synthesis of a color reagent 2,6-dibromo-4-nitrobenzene diazoaminoazobenzene (DBNDAA) and its color reaction with cadimum have been studied. The results show that in the presence of Tween 80-sodium dodecyl benzene sulfonate and in the medium at pH 8. 0-12. 0 DBNDDA reacts with Cd(Ⅱ) to form stable complex(3 :1).The molar absorptivity of the color complex is 1. 52×105L · mol-1· cm-1 at 500nm. Beer's law is obeyed in the range of 0-28μg Cd/25ml. The dissociation constant of the reagent and the instability constant of the complex have been determined. The method has been applied to the spectrophotometric determination of trace cadmium in alunimium alloy .standard water sample and waste water with satisfactory results.