分子印迹掺杂金属有机框架固相萃取-高效液相色谱-串联质谱法测定大米中10种磺酰脲类除草剂

为研发能同时检测多种磺酰脲类农药的高效方法,本研究以甲磺隆为模板分子,4-乙烯吡啶(4-VP)为功能单体,乙二醇二甲基丙烯酸酯(EGDMA)为交联剂,利用沉淀聚合法合成分子印迹聚合物(MIP)。将其与制备的金属有机框架(MOFs)材料掺杂混合作为复合填料制成MOFs-MIP固相萃取柱,结合高效液相色谱-串联质谱(HPLC-MS/MS),建立了大米样品中单嘧磺隆、甲磺隆、噻吩磺隆、氯磺隆、氟磺隆、氟胺磺隆、氯嘧磺隆、烟嘧磺隆、苄嘧磺隆、吡嘧磺隆共10种磺酰脲类除草剂残留的高通量痕量分析方法。采用扫描电镜分别对MIP和MOFs材料的表面形态进行表征,优化活化液、上样液、淋洗液和洗脱液等固相萃取条件。结果表明,5 mL乙腈、5 mL水为活化液,80%乙腈-水为上样液,3 mL水淋洗,10 mL乙酸-甲醇(1:9,V/V)与5 mL丙酮先后洗脱,40 mg MIP与10 mg MOFs材料混合作为SPE柱填料配比,此时检出限(LOD)在0.07~0.5 μg/kg之间,样品浓度在1~100 μg/kg范围内线性关系良好(R²>0.991),回收率在79.75%~99.05%之间,相对标准偏差在6.7%~13.8%之间。本方法具有检测灵敏度高、稳定性强等优点,可实现对大米样品中磺酰脲类除草剂残留的类特异性快速检测。

Determination of 10 Sulfonylurea Herbicides by High Performance Liquid Chromatography-Tandem Mass Spectrometric with Molecularly Imprinted Polymers Solid Phase Extraction Doped Metal Organic Frameworks

To develop an efficient method for simultaneous detection of sulfonylureas,molecularly imprinted polymer(MIP)was successfully synthesized by precipitation polymerization using metsulfuron-methyl as template,4-ethylene pyridine(4-VP)as functional monomer and ethylene glycol dimethacrylate(EGDMA)as crosslinker. A mixed solid-phase extraction cartridge was obtained by packing the MIP and the metal organic frameworks(MOFs)at proper amount. A high throughput method was established for trace analysis of 10 kinds of sulfonylurea herbicide pesticides(monosulfuron,metsulfuron-methyl,thifensulfuron,chlorsulfuron,prosulfuron,triflusulfuron-methyl,chlorimuron-ethyl,nicosulfuron,bensulfuron-methyl and pyrazosulfuron-ethyl)in rice samples by the mixed solid phase extraction coupled with HPLC-MS/MS.The characterizations of the MIP and MOFs were respectively performed with scanning electronic microscope. The solid phase extraction conditions including activator,loading solutions,washing solutions and elution solutions were optimized. The results showed that the optimal conditions were:Acetonitrile(5 mL) and water(5 mL) as activation solution,acetonitrile water(80%)as sample solution,water(3 mL)for elution,10 mL of acetic acid methanol(1:9,V/V)successively eluted with 5 mL of acetone,MIP(40 mg)mixed with MOFs(10 mg)as SPE column packing ratio. Under the optimum conditions,the limit of detection(LOD)ranged from 0.07 to 0.5 μg/kg. It showed a good linearity relationship in the range of 1~100 μg/kg with the relative coefficient(r>0.991). Besides,the average recoveries was in the range of 79.75%~99.05% with the relative standard deviation(RSD,n=3)of 6.7%~13.8%.The developed method possessed many advantages such as high sensitivity and strong stability,and would be suitable for the rapid and class-specific determination of sulfonylurea herbicide pesticides in rice samples.