基于石墨烯材料整体柱的构筑及固相萃取食品中兽药残留研究

The novel hybrid monolithic columns based on graphene materials is fabricated as a novel sample pretreatment sorbent for solid-phase extraction of veterinary drug residues in animal derived food matrices. To avoid the difficulties in the packing of nanothickness graphene materials into the column format, poor selectivity and reproducibility, and still take advantages of the superior qualities of graphene materials, preparation of the graphene-based monolithic column is a good choice. It is a hybrid matrix that combines the porous "single particle" structure of monolithic column format with exceptional thermal and mechanical properties, ultrahigh specific surface area and facile interaction inherited from graphene materials. The method is based on the C=C copolymerization between graphene-based materials and the vinyl monomers via free radical polymerization to form a novel continuous porous monolithic column with uniform graphene sheets well arranged in a convenient format, which is different from the method using the physcial incorpotation of graphene directly. Furthermore, in order to improve the compatibility and provide the electrostatic and hydrophilic interaction with veterinary drug residues, graphene for the monolith fabrication is first modified to obtain graphene oxide, carboxylic graphene oxide and polyethylene glycol functionalized graphene oxide. Using high performance liquid chromatography-tandem mass spectrometry, the interaction mechanisim between the monolith and the selected veterinary drug including triazine, clenbuterol, nitroimidazole and carbadox is studied. The on-line cleanup solid-phase extraction process is realized on the monolithic column and the determination of triazine, clenbuterol, nitroimidazole and carbadox veterinary drug residues in animal derived food matrices is carried out by high performance liquid chromatography -tandem mass spectrometry . In summary, the proposed strategy gives excellent performance as a novel sample pretreatment technique for veterinary drug residues from complex matrices and plays a key role in the aeras of solid-phase extraction and human food safety.

本项目旨在发展基于石墨烯材料杂化聚合物整体柱固相萃取动物源性食品中兽药残留的样品前处理新方法。为了克服石墨烯材料填充柱填充困难，选择性和重现性受限等缺点，同时发挥石墨烯本身特点和整体柱的结构优势，项目打破石墨烯复合材料简单的物理掺杂模式，利用石墨烯材料与含有双键的聚合单体的共聚反应构筑石墨烯材料固定排列的整体柱。同时对石墨烯进行氧化、羧基化和聚乙二醇修饰，一方面提高材料的生物兼容性，另一方面引入的基团可与兽药产生静电作用和亲水作用。结合在线净化高效液相色谱串联质谱分析，研究整体柱与弱极性三嗪类，离子型克伦特罗、硝基咪唑类和喹口恶森类兽药的作用机理。建立基于该类整体柱在线净化固相萃取与液相色谱串联质谱联用测定动物源性食品中三嗪类，克伦特罗等兽药残留分析的新方法。本项目将为复杂样品中低含量物质的高效、高选择性富集提供新技术，对于固相萃取材料的发展和食品安全研究具有重要意义。

由于食品样品基质复杂、待测物含量低，在分析时难以直接测定，样品前处理环节就成为食品中药物残留分析的关键，它决定了整个分析方法的分析时间、准确度和成本。因此发展简单、快速的前处理方法具有重要的价值。项目利用石墨烯材料本身性质稳定、比表面积大、作用强等优势，结合整体柱连续多孔、制备简单的特点，通过热引发自由基聚合反应得到便于使用的、结构连续、均一的石墨烯整体柱，将该整体柱前处理材料作为在线净化柱与液相色谱质谱仪联用，成功用于动物源性食品中磺胺类药物、喹诺酮类抗菌药等兽药残留分析。方法实现了前处理与仪器分析的在线自动化，简单快速。传统方法步骤繁琐，仅仅是前处理就需要几个小时，而本法整个分析时间仅仅需要几十分钟；与离线萃取柱的一次性使用相比，该净化柱能够重复使用上百次。另外，在此基础上开发了反相和离子交换型在线净化固相萃取柱，用于食品中非法添加苏丹红和农兽药残留分析。本项目为复杂样品中低含量物质的高效快速分析提供新方法，对于固相萃取材料的发展和食品安全研究具有重要意义。