以甲基丙烯酸为功能单体，乙二醇二甲基丙烯酸酯为交联剂对Fe3 O4纳米粒子进行改性，利用红外光谱、元素分析和透射电镜对改性粒子( Fe3 O4@MAED)进行表征。同时将Fe3 O4@MAED用于萃取环境水样和果汁中苯甲酰脲类杀虫剂，详细考察了磁性粒子用量、解析溶剂、吸附和解析时间、pH值、离子强度等因素对萃取性能的影响。在此基础上，与高效液相色谱/二极管阵列检测器联用，建立了环境水样和果汁中苯甲酰脲类杀虫剂的快速、简便、灵敏的测定方法。在最佳实验条件下，本方法具有较宽的线性范围、良好的线性相关系数(R2>0.99)和理想的灵敏度。对于水样和果汁样品，该杀虫剂的检测限分别在0.10~0.19μg/L和0.12~0.30μg/L之间，日内相对标准偏差小于7％，日间相对标准偏差小于11％。在实际环境水和果汁样品中，不同加标浓度苯甲酰脲的回收率在69.4％~118％之间。研究表明，所制备的Fe3 O4@MAED可通过疏水、氢键、离子交换等多重作用力实现对目标物的有效萃取。%A magnetic extraction sorbent based on Fe3 O4@poly ( methacrylic acid-co-ethylene dimethacrylate) ( Fe3 O4@MAED ) was synthesized using methacrylic acid and ethylene dimethacrylate as monomer and cross-linker, respectively. The magnetic sorbent was characterized by FTIR spectroscopy, elemental analysis and transmission electron microscopy. At the same time, the Fe3 O4@MAED was used to extract four benzoylurea pesticides in water and juice samples under magnetic dispersive solid phase microextraction ( MDSPME ) format. To obtain the optimal extraction conditions, several parameters, including the amount of sorbent, desorption solvent, extraction and desorption time, pH value, and ionic strength in sample matrix were investigated. Based on this, a fast, simple and sensitive method for the determination of benzoylurea pesticides in water and juice samples was developed by the combination of MDSPME with HPLC equipped with diode array detector. Under the optimized experimental conditions, the developed method possessed expected linear dynamic ranges, coefficients of correlation ( R2>0. 99 ) and sensitivity. The limits of detection (S/N=3) for target analytes were 0. 10-0. 19 μg/L in water and 0. 12-0. 30 μg/L in juice, respectively. The RSDs for intra-day were less than 7% and inter-day RSDs were less than 11%. The developed method was successfully applied to the determination of benzoylurea pesticides residues in water and juice samples and the recoveries of spiked target compounds were in the range of 69. 4%-118. 0%. The results demonstrated that the Fe3 O4@ MAED could extract benzoylurea pesticides effectively through multi-interactions including hydrophobic, hydrogen-bond and ion-exchange interactions between sorbent and analytes.
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