摘要
本文报道了高灵敏度高选择性测镉新试剂——2-氯-4-硝基苯基重氮氨基偶氮苯的合成、纯化及结构鉴定。研究了该试剂在不同表面活性剂存在下的酸性离解行为及其与镉(Ⅱ)的显色反应。实验结果表明,在Triton x-100存在下,于pH7.80的磷酸二氢钾-氢氧化钠缓冲介质中。镉(Ⅱ)可与该试剂形成稳定的红色配合物,其最大吸收波长位于505mm处,摩尔吸光系数为1.57×10~5L·mol^(-1)·cm^(-1)镉量在0～12μg/25mL范围内符合比尔定律。在所拟测定条件下,方法选择性甚佳,只有Ag^+、Hg^(2+)、Cu^(2+)离子产生干扰,可通过加入适当的掩蔽剂予以消除。方法可不经分离直接用于环境水样、工业废水及铝合金标样中痕量镉(Ⅱ)的测定,结果满意。
The synthesis, purification and structural identification of 2-Chloro-4-nitrobenzenediazoamino-azobenzene (CNDAA) have been investigated. The behavior of acid dissociation of the reagent in the presence of different kinds of surfactant and its color reaction with cadmium have also been studied. Experimenal results show that in the presence of Triton X-100 and at pH7. 80 the reagent reacts with cadmium (Ⅱ) to form a stable red complex with a maximum absorbance at 505nm. Its apparent molar absorptivity is found to be 1.57×10~5L·mol^(-1)·cm^(-1). Beer's law is obeyed in the range of 0～12μg Cd (Ⅱ) per 25mL. The proposed method has a good selectivity. Only Ag(-Ⅰ),Cu(Ⅱ) and Hg(Ⅱ) interfere. These interferences may be eliminated by adding a mixed masking agent of sodium fluoridethiourea. The method has been used for the direct determination of trace cadmium in standard water sample,industrial waste waters and aluminium alloys with satisfactory results.
出处
《分析试验室》
CAS
CSCD
北大核心
1993年第4期58-62,共5页
Chinese Journal of Analysis Laboratory
基金
煤炭青年科学基金
关键词
分光光度分析
显色剂
镉
Cadmium determination
spectrophotometry
2-chloro-4-nitrobenzenediazoaminoazobenzene (CNDAA)
waste water analysis
standard water sample analysis
aluminium alloy analysis
