混合胶束协同增敏光度法测定水中痕量铜

Spectrophotometric determination of trace copper in water with co-enhanced sensitivity of mixed surfactants

研究了溴化十六烷基三甲基铵（CTMAB）和乳化剂聚乙二醇辛基苯基醚（OP）组成的混合胶柬对铬天青S与铜（Ⅱ）显色反应的增敏作用，建立了分光光度法测定水中痕量铜㈤的新方法。结果表明：在pH9．0的NaAc—Na2HPO4缓冲溶液介质中，铜（Ⅱ）与铬天青S，CTMAB，OP形成绿蓝色络合物，λmax=609nm，表观摩尔吸光系数为9．85×10^4L·mol·cm^-1。铜的质量浓度在0～1．2mg／L范围内与吸光度呈良好的线性关系，相关系数为r=0．9998，检出限为0．0022μg／mL。应用该方法对管网水和湖水中的铜进行测定，相对标准偏差分别为1.49％和3．08％，加标回收率为97％～103％。

The enhanced sensitivity effect of mixed surfactants containing CTMAB and OP on color reaction of chrome azurol S（CAS） with copper（Ⅱ） was studied, and a new method to determine trace copper in water by spectrophotometry was established. The results showed that Cu^2＋ reacts with CAS, CTMAB and OP to form a green blue complex in the NaAc-Na2 HPO4 buffer solution at pH 9.0. The maximum absorption wavelength was 609 nm. The apparent molar absorptivity was 9.85× 10^4 L · mol^-1·cm^-1. The absorbance showed good linearity with Cu^2＋ in the range of 0-1.2 mg/L ,and the correlation coefficient is 0. 999 8. The detection limit of this method is 0. 002 2μg/mL. The proposed method has been applied to the determination of Cu^2＋ in tap water and lake water samples with the relative standard deviation of 1.49% and 3.08%, and the recovery of 97%--103%.