集SPME富集靶标农药和功能磁性材料除杂一体化协同净化技术研究

Food safety is a focus subject in China, even worldwide. How to quickly lock the pollutant and achieve the primary screening is a significant issue in pesticide residue analysis. Another issue is how to purify the complex matrix and obtain accurate quantification. The present work aims at to address the abovementioned problem based on solid phase microextraction (SPME) technology and functional magnetic materials. A novel integrated cooperative purification method is proposed to achieve the simultaneous extraction of target pesticides and removal of the matrix interferences..Functional magnetic materials (FMAs) are synthesized to selectively remove the interferences existed in the complex matrixes, such as milk, juice and fruits with high-sugar content. In these matrixes, protein, sugar, organic acids and pigment are main interferences. FMAs with high adsorption ability and strong magnetic force were prepared through adjusting the reaction conditions. Triazoles fungicides are selected as target pesticides to systematically investigate the impossible influencing factors, such as combination of FMAs and their amounts, SPME fibers, extraction media (pH, organic modifier, etc) and desorption conditions and so on. The principle component analysis is used to screen the key factors through reducing the data dimensionality. Method validation and comparison with traditional methods are performed to evaluate its feasibility. This integrated method let the extraction of target pesticides and removal of interference accomplish simultaneously. The cooperative purification largely improves analysis efficiency and accuracy, which is valuable for achieving rapid screening of pesticides and accurate quantification.

食品质量安全是我国乃至全球关注的焦点，如何快速锁定污染物，实现初步筛查；针对复杂基质，如何在快速分析同时净化样品，实现准确定量，是残留分析有待解决的重要问题。本项目拟基于SPME富集靶标农药和功能磁性材料去除杂质的原理研制一体化协同净化技术，以期同时解决上述两个关键问题。.针对牛奶、果汁、高糖果蔬复杂基质中蛋白质、糖、有机酸、色素等杂质，有针对性地研制功能磁性材料，调控反应条件获得吸附性强、磁力高的材料及制备条件。以三唑类杀菌剂为研究模型，构建一体化协同净化方法，优化磁性材料组合及用量、萃取纤维、萃取介质、解吸条件等参数设置，以提高靶标药物灵敏度和基质净化效果。结合主成分分析数据降维筛选关键调控因子；通过方法验证和比对全面评估其可行性。该方法使SPME选择性萃取靶标农药和磁性材料去除大分子杂质同时进行，协同净化过程有效提高分析效率和准确度，对实现快速农药残留筛查定量具有现实借鉴意义。

本研究基于固相微萃取（SPME）与磁纳米材料的技术特点创新性地提出一体化协同净化技术构建思路。研制具有定向吸附功能的磁纳米材料以去除复杂基质中的主要杂质，与SPME高效富集靶标化合物的功能相结合，利用两者的协同作用构建新型一体化、双重净化技术平台。本研究成功研制核壳型磁性纳米材料Fe3O4-PSA 、Fe3O4-PDA和Fe3O4-TiO2，以选择性吸附极性有机酸、多糖及蛋白与脂类杂质。在一体化平台构建中，首先优化三唑类农药的SPME分析条件，然后分别以果汁、茶饮料和牛奶为代表基质，以23种三唑类农药为研究对象，探索添加磁材料对三唑类农药的响应灵敏度的影响。结果发现，磁材料的加入确实会降低化合物的响应，但是可以延长SPME探针的使用频次，说明磁材料也可以吸附基质中的杂质。因此，进一步利用正交实验设计探讨磁纳米材料，萃取时间以及有机试剂用量等条件，筛选出最佳的一体化分析方法条件。对于果汁样品，最适宜的SPME一体化分析条件为：磁性材料Fe3O4-PDA用量30mg、甲醇含量10%、萃取时间40min；对于茶饮料，最适条件为：磁性材料Fe3O4-PSA用量30mg、甲醇含量0%、萃取时间40min；对于牛奶样品，最适条件为：磁性材料Fe3O4-TiO2用量20mg、甲醇含量10%、萃取时间40min。系统的方法验证工作结果表明，在2-200 μg /L范围内，23种三唑类农药在果汁、茶饮料和牛奶中均表现出很好的线性，相关系数R均大于0.99。果汁中各农药组分的LOD范围为0.01~0.2 μg /L，LOQ范围为0.05~0.67 μg /L；茶饮料中LOD范围为0.02~0.19 μg /L，LOQ范围为0.06~0.64 μg /L；牛奶中LOD范围为0.15~0.60 μg /L，LOQ范围为0.51~2.01 μg /L。采用基质匹配标准溶液进行样品回收率测定结果表明，果汁、茶饮料样品中三唑类农药的回收率均可满足分析测试要求，而牛奶中部分药物存在测定精密度偏差较大的现象，说明牛奶样品基质复杂，分析方法仍需进一步优化。此方法较常规法简单、操作便捷、可靠，且环境友好，因为在前处理中省略了国标法中的有机溶剂处理程序，故不产生相应的有机废弃物，同时也减少了很多一次性实验用品的消耗，值得继续完善并加以推广。