磁固相萃取结合高效液相色谱检测农田灌溉水中4种苯甲酰脲类农药

采用溶剂热法制备了磁性金属有机骨架吸附剂Fe_3O_4-NH_2@MIL-101,通过电子显微镜、红外光谱、X射线衍射对吸附剂的形貌和组成进行了表征,磁强计对吸附剂的磁强度进行了测定。使用该吸附剂进行磁固相萃取,结合高效液相色谱-紫外检测,对农田灌溉水中4种苯甲酰脲类杀虫剂(氯吡脲、氟幼脲、氟铃脲和虱螨脲)进行分析。实验对吸附和洗脱条件进行了优化,包括吸附剂用量、吸附时间、pH值、离子强度、洗脱溶剂种类以及洗脱时间和体积。在最佳实验条件下,方法能够有效富集灌溉水中的苯甲酰脲类杀虫剂。4种苯甲酰脲类杀虫剂在0. 010～3. 0 mg/L浓度范围内线性关系良好,相关系数(r)均大于0. 999 5,检出限为0. 03～0. 09μg/L,定量下限为0. 10～0. 30μg/L。方法的加标回收率为81. 7%～95. 4%,RSD小于10%。该方法前处理操作简便,萃取用时不超过15 min,可用于农田灌溉水中苯甲酰脲类杀虫剂的检测。

Determination of 4 Benzoylurea Pesticides in Irrigation Water by High Performance Liquid Chromatography with Magnetic Solid phase Extraction

A method of high performance liquid chromatography( HPLC) with magnetic solid-phase extraction( MSPE) was developed for the determination of four benzoylurea pesticides,i. e. forchlorfenuron,penfluron, hexaflumuron and lufenuron in irrigation water. A magnetic metal organic framework sorbent( Fe3O4-NH2@MIL-101) was fabricated via solvothermal method. The composition and morpholgy of the composite were characterized by scanning electron microscopy( SEM),Fourier transform infrared spectroscopy( FT-IR) and X-ray diffraction( XRD) analysis. Meanwhile,the magnetic intensity of the material was detected with a vibrating sample magnetometer. The determination of four analytes was performed by HPLC with the synthesized composite as MSPE adsorbent.The adsorption and elution factors,including adsorbent amount,adsorption time,p H value,elution time and elution volume,were investigated. Under the optimum conditions,the calibration curves for four benzoylurea pesticides showed good linear relationships in the range of 0. 010-3. 0 mg/L with correlation coefficients( r) higher than 0. 999 5. The detection limits and the quantitation limits were in the ranges of 0. 03-0. 09 μg/L and 0. 10-0. 30 μg/L,respectively. The recoveries at three spiked levels ranged from 81. 7% to 95. 4% with RSD less than 10%. With a simple pretreatment process and an extraction time within 15 min,the method could be applied in the analysis on trace residues of benzoylurea pesticides in irrigation water.