Abstract: Avermectin, as a broad-spectrum and highly effective antiparasitic drug, is commonly used to treat diseases in dairy cows and prone to remain in the body and can enter the food chain through milk, posing a threat to human health. In this study, a core-shell covalent organic framework composite (Fe3O4@TabDmtp) was prepared by a solvothermal self-assembly method using 1,3,5-tris(4-aminophenyl)benzene (Tab) and 2,5-dimethoxyterephthalaldehyde (Dmtp) as organic monomers. Fe3O4@TabDmtp was characterized by Fourier transform infrared spectroscopy, transmission electron microscopy and vibrating sample magnetometer. Fe3O4@TabDmtp was used as an adsorbent for the magnetic solid-phase extraction (MSPE) of avermectin, and the effects of eluent type and volume, adsorbent dosage, extraction time, pH and ionic strength on the extraction efficiency were investigated. Under the optimal extraction conditions, a new fluorescence method for the determination of avermectin was established. The?calibration curve for avermectin exhibited good linearity in the concentration range of 0.02–10 μg/mL with a correlation coefficient of 0.998. The limit of?detection and limit of?quantification were 0.006 and 0.02 μg/mL at signal-to-noise ratio of 3 and 10, respectively. Recovery rates for spiked samples ranged from 98.36% to 114.76%. In conclusion, the pretreatment method is time saving and Fe3O4@TabDmtp can be reused, and the analytical method has high accuracy, strong stability and high resistance to matrix interference. It can be applied to the rapid detection of avermectin in whole, low-fat and skim milk samples.

Key words: avermectin; covalent organic framework; magnetic solid-phase extraction; fluorescent detection

摘要： 阿维菌素作为常用的广谱、强效抗寄生虫兽药，易在体内残留，随牛乳进入食物链，危害人体健康。以1,3,5-三(4-氨苯基)苯（1,3,5-tris(4-aminophenyl)benzene，Tab）、2,5-二甲氧基苯-1,4-二甲醛（2,5-dimethoxyterephthalaldehyde，Dmtp）为有机单体，利用溶剂热自组装制备核壳型共价有机骨架复合材料Fe3O4@TabDmtp，通过傅里叶变换红外光谱、透射电子显微镜、振动样品磁强计对Fe3O4@TabDmtp吸附剂进行表征。基于Fe3O4@TabDmtp磁固相萃取技术，系统考察洗脱溶剂种类与体积、吸附剂用量、萃取时间、pH值及离子强度对萃取效果的影响。在最优萃取条件下，结合荧光检测方法，建立阿维菌素磁固相萃取-荧光检测新方法。结果表明，阿维菌素在0.02～10 μg/mL范围内呈现良好的线性关系（相关系数0.998），检出限（信噪比（RSN）＝3）为0.006 μg/mL，定量限（RSN＝10）为0.02 μg/mL，加标回收率为98.36%～114.76%。综上，方法前处理时间短，磁性固相萃取材料Fe3O4@TabDmtp可循环使用，检测方法具有较高的准确度及较强的稳定性和基质抗干扰能力，可应用于全脂、低脂和脱脂牛乳样品中阿维菌素的快速检测。

关键词: 阿维菌素；共价有机骨架；磁固相萃取；荧光检测