氯磺酚偶氮罗丹宁分光光度法测定天然水中痕量铜(Ⅱ)

Determination of Trace Amounts of Copper(Ⅱ) in Natural Water by Spectrophotometry with Sulfochlorophenolazorhodanine

在pH5.56的醋酸盐缓冲溶液中,Cu(Ⅱ)和氯磺酚偶氮罗丹宁(SCPA)生成二元配合物Cu(SCPA)2,利用光谱修正技术表征配合物的分子结构。选择吸收光谱峰谷波长530nm和418nm为工作波长,测定显色溶液及空白溶液的吸光度A530nm,A418nm及A5030nm,A4018nm。计算光吸收比差值(ΔAr)。当Cu(Ⅱ)浓度在0.200μg/mL以内与ΔAr值之间呈线性关系,方法检出限为2ng/mL,有利于直接监测天然水。本实验已测定了黄浦江、长江、太湖水样中的痕量Cu(Ⅱ),结果与电感耦合等离子体-发射光谱法的测定结果相符,方法回收率在97.0%—103.5%之间。

In an acetate buffer medium of 5.56,a binary coordination of Cu（SCPA）2 was formed by the reaction of Cu（Ⅱ） with sulfochlorophenolazorhodanine（SCPA）,and its molecular structure was characterized by the spectral correction method.Wavelengths of the crest and trough in the absorption spectrum of the coordination complex were found at 530nm and 418nm respectively.Values of absorbance of the colored complex solution and the blank solution were measured at both wavelengths（recorded as A530nm,A418nm and A0530nm and A0418nm）.The content of Cu（Ⅱ） ion was linear with ΔAr in the range within 0.200μg/mL,and the detection limit was 2ng/mL.This method is favorable for direct monitoring of natural water.The proposed method was found in the determination of trace amount of copper（Ⅱ） in Huangpu river,Yangtze river and Taihu lake of China,giving results in consistency with the results found by ICP-OES method,and recoveries were from 97.0% to 103.5%.