浊点萃取-分光光度法测定水样中的痕量铜

Cloud point extraction preconcentration for the determination of trace copper in water sample spectrophotometry

提出了浊点萃取-分光光度法测定痕量铜的新方法.该方法基于在pH=7.0时,Cu(Ⅱ)可与8-羟基喹啉(8-Ox)生成疏水性螯合物,被定量萃取进入富胶束相中,从而实现与基体的分离;浓缩物经适当处理后,采用分光光度法进行测定.在NH3-NH4Cl缓冲溶液中,Cu(Ⅱ)-8-Ox络合物最大吸收波长λmax=395 nm,摩尔吸收系数ε=7.69×105L.mol-1.cm-1,检测限为1.28μg.L-1,相对标准偏差(R.S.D.)为4.3%(CCu(Ⅱ)=0.1μg.mL-1,n=6).此种方法已应用于实际天然水样中铜含量的测定,分析结果满意.

A new method for the determination of trace copper in water sample by spectrophotometry with cloud point extraction is put forward. The method is based on the complexation of Cu （ Ⅱ ） with 8 - hydroxyquinoline （8 - Ox） which form an hydrophobic complex and subsequently enter surfactant - rich phase at pH 7. 0. Thus, the separation of Cu （ Ⅱ ） and the matrix could be realized. The concentrated analyte was determined by spectrophotometric methods after proper disposal. At NH3 - NH4Cl buffer solution, the maximum wavelength of absorption ofCu （Ⅱ） -8-Ox complex is 395 nm, ε=7.69×10%5 L· mol%-1 · cm^-1 The limit of detection （LOD） for Cu （Ⅱ） is 1.28 μg L^-1 and the relative standard deviation （RSD） for six replicate measurements of 0.1 μgmL^-1 Cu （Ⅱ ） is 4.3%. The method is applied for the determination of trace copper in water sample successfully and with satisfactory results.