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目的优化超声辅助乳化萃取结合电感耦合等离子体(inductively coupled plasma,ICP)原子发射法,同时测定水样中镉、钴、镍、锌4种金属离子。方法采用吡咯烷二硫代氨基甲酸铵(APDC)溶液作为螯合剂,超声条件下采用二氯甲烷对重金属螯合物进行萃取。优化了缓冲液的p H值,测定了不同加标浓度下方法的回收率。并对自来水、矿泉水、海水等水样进行了测定。结果该方法对Cd、Co、Ni、Zn 4种金属离子在200μg/L加标条件下绝对回收率为27.0%~91.0%,检出限为Cd为0.81μg/L,Co为1.03μg/L,Ni为1.28μg/L,Zn为0.14μg/L。检测实际自来水样,镉、钴、镍、锌4种金属离子相对回收率分别为96.4%、77.4%、120.2%、85.6%,所测自来水中镉、钴、镍、锌4种金属含量分别为1μg/L、0μg/L、2μg/L和146μg/L,均符合国标要求。对矿泉水中镉、钴、镍的相对回收率分别为77.8%,89.9%和74.2%。矿泉水中没有检测到镉、钴两种金属离子,镍含量为1μg/L。结论该方法适合于自来水和矿泉水中部分金属离子的测定,不适合于对海水中金属离子的测定。
OBJECTIVE To optimize ultrasonic assisted emulsion extraction coupled with inductively coupled plasma (ICP) atomic emission spectrometry for simultaneous determination of four metal ions of cadmium, cobalt, nickel and zinc in water samples. Methods The solution of pyrrolidine dithiocarbamate (APDC) was used as the chelating agent and the heavy metal chelates were extracted with dichloromethane under ultrasonic condition. The p H value of the buffer was optimized and the recovery of the method at different spiked concentrations was determined. And tap water, mineral water, sea water and other water samples were measured. Results The absolute recoveries of Cd, Co, Ni and Zn were 27.0% ~ 91.0% under the condition of 200 μg / L spike calibration. The detection limits were 0.81 μg / L for Cd and 1.03 μg / L for Co , Ni was 1.28 μg / L and Zn was 0.14 μg / L. The relative recoveries of four kinds of metal ions of cadmium, cobalt, nickel and zinc in tap water were 96.4%, 77.4%, 120.2% and 85.6%, respectively. The contents of four metals in the tap water such as cadmium, cobalt, nickel and zinc were 1μg / L, 0μg / L, 2μg / L and 146μg / L, all meet the national standard. The relative recoveries of cadmium, cobalt and nickel in mineral water were 77.8%, 89.9% and 74.2% respectively. Mineral water did not detect cadmium, cobalt two kinds of metal ions, nickel content of 1μg / L. Conclusion The method is suitable for the determination of some metal ions in tap water and mineral water and is not suitable for the determination of metal ions in seawater.