强酸性阳离子交换纤维固相萃取-ICP-AES测定食品包装铝材中铜、镍、锌

摘要

Objective:To establish the analysis method for the determination of Ni, Cu and Zn in aluminum food packaging mate-rials by inductively coupled plasma atomic emission spectrometry ( ICP-AES) . Methods: A small amount of EDTA was added to the test solution till the concentration at 0. 010 0 mol·L-1 and the pH value was adjusted to 5. 0. Strong acid cation exchange fibers were used for the assisted extraction of Al3+ with ultrasonic. Al3+ could not quickly form a complex anion with EDTA, so it was adsorbed by the strong acid cation exchange fibers. Cu2+, Ni2+ and Zn2+ could form complex anions with EDTA rapidly, so they could not be ad-sorbed by the strong acid cation exchange fibers and were left in the solution to be determined. Results:After the separation, the con-tents of Cu, Ni and Zn were not lost, and the content of residual aluminum was about 170 times of that of Cu, Ni and Zn, which had not interferece with the determination of Cu, Ni and Zn. The sample standard addition recovery was within the range of 98. 3%-104%with RSD of 0. 2%-2. 5%(n=5). The relative errors between the measured values and the certified values of standard substances were less than 5. 0%. Conclusion:The proposed method can be successfully applied in the separation and determination of Cu, Ni and Zn in aluminum cans, barbecue aluminum foil and standard substances.%目的：：建立用电感耦合等离子体原子发射光谱法( ICP-AES)测定食品包装铝材中Cu、Ni和Zn含量的分析方法。方法：在试液中加入少量EDTA使其浓度为0.0100 mol·L-1,调节溶液pH=5.0,用强酸性阳离子交换纤维对Al3+进行超声辅助萃取,由于Al3+不能与EDTA迅速形成配阴离子,则被强酸性阳离子交换纤维吸附,而Cu2+、Ni2+和Zn2+能与EDTA迅速形成不被强酸性阳离子交换纤维吸附的配阴离子,则留在溶液中待测定。结果：试液经过分离后, Cu、Ni和Zn未见损失,而残留Al的质量浓度约是Cu、Ni、Zn的170倍,不干扰ICP-AES的测定。样品标准加入的回收率均在95.3%~104%之间,RSD在0.2%~2.5%(n=5)之间；标准物质中Ni、Cu和Zn的测定值对认定值的相对误差均小于5.0%。结论：本方法可用于铝制饮料易拉罐、烘烤食品用铝箔和标准物质等样品中Ni、Cu和Zn的测定。