加速溶剂萃取-凝胶渗透色谱法净化-气相色谱-串联质谱法测定土壤中常见的7种农药残留量

Determination of 7 Common Pesticides Residues in Soil by Gas Chromatography-Tandem Mass Spectrometry Coupled with Accelerated Solvent Extraction and Gel Permeation Chromatography Purification

建立了加速溶剂萃取(ASE)-凝胶渗透色谱法(GPC)净化-气相色谱-串联质谱法(GC-MS/MS)测定土壤中的7种农药(五氯硝基苯、多效唑、腐霉利、甲霜灵、醚菊酯、啶虫脒和咪鲜胺)残留量的分析方法。随机采集种植土壤样品,于35℃烘干压碎后过2 mm孔径筛;称取过筛后的土壤样品10 g于加速溶剂萃取池中,以体积比为1∶1的丙酮-正己烷混合液为萃取剂,采用ASE反复萃取3次;将收集到的萃取液全部转移至GPC净化瓶中,经GPC净化后氮吹至近干,残渣用1 mL正己烷溶解,0.45μm微孔滤膜过滤,滤液进GC-MS/MS仪,多反应监测(MRM)模式分析,外标法定量。结果显示:7种农药的质量浓度在0.04~4.0 mg·L^(-1)内与其峰面积呈线性关系,检出限(3S/N)为0.002~0.007 mg·kg-1;对空白样品进行3个浓度水平的加标回收试验,7种农药的回收率为88.9%~104%,测定值的相对标准偏差(n=6)均小于4.0%。方法用于实际样品分析,检出了腐霉利和啶虫脒,检出量分别为0.010,0.005 mg·kg-1。

A method of gas chromatography tandem mass spectrometry(GC-MS/MS)coupled with accelerated solvent extraction(ASE)and gel permeation chromatography(GPC)purification for the determination of 7 pesticides(quintozene,paclobutrazol,procymidone,metalaxyl,ethofenprox,acetamiprid and prochloraz)residues in soil was established.Soil samples were randomly collected and passed by 2 mm sieve after drying at 35℃and crushing.Screened soil sample of 10 g was placed in the accelerated solvent extraction tank,and extracted repeatedly 3 times by ASE with extraction solvent of a mixture of acetone and hexane at volume ratio of 1∶1.The extracted solution was purified by GPC and blown to nearly dryness by nitrogen.The residue was dissolved by hexane of 1 mL and filtered by 0.45μm microporous membrane,then MRM mode was adopted in GC-MS/MS analysis,and external standard was used for quantification.As found by results,linearity relationships between mass concentrations of 7 pesticides and their peak areas were kept in the range of 0.04-4.0 mg·L^(-1),with detection limits(3 S/N)in the range of 0.002-0.007 mg·kg-1.Recovery test was made on blank samples at 3 concentration levels,giving recovery of 7 pesticides in the range of 88.9%-104%,and RSDs(n=6)of the determined values less than 4.0%.The method was used for the analysis of actual samples,and promolide and acetamiprid were detected,with detection amounts of 0.010,0.005 mg·kg-1,respectively.