微波消解-浊点萃取-石墨炉原子吸收光谱法测定铜尾矿中痕量铜

GF-AAS Determination of Trace Amount of Copper in Copper Tailings with Microwave Assisted Sample Digestion and Separation by Cloud Point Extraction

铜尾矿在微波消解仪中经盐酸-硝酸（3＋1）溶液和过氧化氢消解。从所得消解液中分取部分试液，加入1-（2-吡啶偶氮）-2-萘酚（PAN）溶液、Triton X-100溶液、pH6．0的氢氧化钠-磷酸二氢钾缓冲溶液及饱和氯化钠溶液，加水定容至15mL，于70℃加热30min，使铜（Ⅱ）与PAN络合并溶入Triton X-100相中，实现铜（Ⅱ）的浊点萃取分离。弃去水相，于Triton X-100相中，加入水及3滴盐酸，用石墨炉原子吸收光谱法测定其中的铜量。铜的质量浓度在0．5～20μg·L^-1范围内与吸光度呈线性关系，检出限（3a）为0．36μg·L^-1。应用本方法分析了铜尾矿样品，并用标准加入法做回收试验，测得回收率在101％～105％之间，测定值的相对标准偏差（n=6）在3．00o～3．8％之间。

Sample of copper railings was digested with a mixture of HCl-HNO3 （ 3 ＋ 1 ） and H2O2 in a microwave digestor. An aliquot was taken from the solution obtained and 1-（2-pyridineazo）-2-naphthol （PAN）, Triton X-100, NaOH-KH2PO4 buffer solution of pH 3. 0 as well as NaCl saturated solution were added. After diluting to 15 mL with water, the solution was heated at 70 ℃ for 30 rain, to have the Cu^2＋ separated in form of its complex with PAN by the cloud point extraction. After discarding the water phase, the Triton X-100 phase was taken up with water and 3 drops of HCl. The content of copper in this solution was determined by GF-AAS. Linear relationship between values of absorbance and mass concentration of Cu^2＋ was kept in the range of 0. 5--20 μg · L^-1 , with detection limit （3σ） of 0. 36μg · L ^-1. The proposed method was applied to the analysis of a sample of copper tailings, and recovery was tested by standard addition method giving values of recovery and RSD＇s （n=6） in the ranges of 101%- 105 % and 3.0%- 3.8% respectively.