分子印迹固相萃取-高效液相色谱法用于奶粉样品中痕量三聚氰胺的残留检测

目的以三聚氰胺为模板分子,制备一系列三聚氰胺分子印迹聚合物(molecularly imprinted polymers,MIPs),将MIPs作为固相萃取吸附剂,与高效液相色谱联用检测奶粉样品中残留的痕量三聚氰胺。方法采用沉淀聚合法依次优化致孔剂种类、功能单体与模板分子之间的摩尔比、交联剂的用量,得到对三聚氰胺具有特异性识别能力和高吸附容量的分子印迹聚合物,对60mL奶粉样品提取液中痕量三聚氰胺进行净化和富集。结果萃取回收率为85.1%～99.7%,固相萃取过程不但可以避免繁琐的样品浓缩过程,缩短了样品前处理时间,而且降低了二次污染。方法的加标回收率为89.7%～100.6%,相对标准偏差(RSD)不高于3.1%。与国家标准方法(GB/T 22388-2008)所用的萃取柱(MCX)相比,MIPs萃取柱表现出更好的净化和富集效果。结论建立了一种奶粉样品中痕量三聚氰胺的残留检测方法,为监控食品样本中痕量三聚氰胺残留检测提供有力的技术支持。

Molecularly Imprinted Solid-phase Extraction Coupled with High Performance Liquid Chromatography for Determination of Trace Melamine in Milk Powder

Objective A series of molecularly imprinted polymers(MIPs)were prepared by precipitation polymerization and coupled with high performance liquid chromatography for determination of trace melamine in milk powder.Methods MIPs were prepared using melamine and the conditions of polymerization,including porogen,cross-linker,the molar ratio of functional monomer and template,were studied to obtain the optimized MIPs with specific recognition ability and high adsorption capacity.Subsequently,it was used as the sorbents of solid phase extraction(SPE)to purify and enrich 60 mL extracted solution.Results The recovery was changed from 85.1% to 99.7%.The molecular imprinting solid phase extraction procedure not only avoided the tedious procedure of sample preconcentration and shortened the analytical time,but also reduced the opportunity of pollution.Compared with MCX column recommended by national standard method(GB/T 22388-2008),purification effect and recovery of the MIPs column were more satisfactory.The spiked recovery of this method was changed from 89.7%—100.6% and the RSD was lower than 3.1%.Conclusion A simple and sensitive method using MIPs as the sorbents of SPE was applied to determine trace melamine in milk powder,which could meet the needs of the routine testing work.