超声辅助萃取-电感耦合等离子体原子发射光谱仪联用同时测定水样中多种金属离子

摘要

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 pH 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 the ultrasonic-assisted emulsification extraction combined with inductively coupled plasma atomic emission spectrometry (ICP-OES) in order to determinate the concentration of cadmium, cobalt, nickel and zinc in water simultaneously.MethodsAmmonium pyrrolidinedithio carbamate (APDC) was used as a chelating agent, and dichloromethane was used as the extraction reagent of the heavy metal chelating ultrasonic extraction. The pH of the buffer was optimized, and the recovery of every metal ion was measured at different spiked concentration. And the concentration of metal ions in tap water, mineral water and sea water were determined. Results The absolute recovery of Cd, Co, Ni, Zn 4 kinds of metal ions in 200 μg/L spiked conditions were between 27.0%~91.0%, and the detection limits of method were Cd 0.81 μg/L, Co 1.03 μg/L, Ni 1.28 μg/L and Zn 0.14 μg/L. This method had good application in tap water sample, the relative recoveries of cadmium, cobalt, nickel and zinc metal ions were 96.4%, 77.4%, 120.2% and 85.6%. The metal content of cadmium, cobalt, nickel, and zinc were 1 μg/L, 0 μg/L, 2 μg/L and 146 μg/L in the tap water, that were in line with the national standard. The relative recovery of cadmium, cobalt and nickel were 77.8%, 89.9% and 74.2% in the mineral water. The cadmium, cobalt metal ions were not detected, and the nickel content was 1 μg/L in mineral water. Conclusion The ultrasonic-assisted emulsification extraction combined with ICP-OES method is suitable for the determination of some metal ions in tap water and mineral water, but not suitable for the determination of metal ions in seawater.