QuEChERS结合UPLC-MS/MS法测定海南豇豆中倍硫磷及其Ⅰ型代谢物农药残留

Determination of fenthion and its typeⅠmetabolites in cowpea in Hainan by UPLC-MS/MS combined with QuEChERS

[目的]建立QuEChERS结合UPLC-MS/MS法测定海南豇豆中倍硫磷及其Ⅰ型代谢物的分析方法。[方法]样品经乙腈提取,氯化钠盐析,石墨化炭黑(GCB)和N-丙基乙二胺(PSA)分散固相萃取净化,以Agilent ZORBAX Eclipse Plus C18柱为分离色谱柱,多反应监测(MRM)模式下检测倍硫磷及其Ⅰ型代谢物,定量分析采用溶剂标准曲线法(外标法)。[结果]倍硫磷及其Ⅰ型代谢物在2.0~100.0μg/L质量浓度范围内线性关系良好,相关系数(r)大于0.999;以海南豇豆阴性样品为基质,在2、5、10、50μg/kg 4个质量分数加标水平下,倍硫磷及其Ⅰ型代谢物的平均加标回收率为89.3%~99.3%,相对标准偏差(RSD)为1.2%~7.3%,方法定量限均为2μg/kg。[结论]方法具有简便、高效、准确、廉价等特点,适用于豇豆中倍硫磷及其Ⅰ型代谢物的同时测定。方法的建立可为相关监管部门对豇豆中倍硫磷及其Ⅰ型代谢物农药污染的有效监测提供技术支撑。

[Aims]A method was established for analysis of fenthion and its typeⅠmetabolites in cowpea in Hainan by using QuEChERS purification combined with UPLC-MS/MS for determination.[Methods]The samples were extracted by acetonitrile,salted out with sodium chloride,purified with graphitized carbon black(GCB)and N-propylethylenediamine(PSA).The pesticides were separated with Agilent ZORBAX Eclipse Plus C18.Fenthion and its typeⅠmetabolites were analyzed by UPLC-MS/MS with multiple reaction monitoring(MRM)mode.The solvent standard calibration curve was used for quantitative analysis with external standard method.[Results]The results showed that the good linear relationships were obtained for fenthion and its typeⅠmetabolites in the concentration range from 2 to 100μg/L.The correlation coefficients(r)were greater than 0.999.The average spiked recoveries for blank cowpea at 4 levels of 2,5,10,50μg/kg were in the range of 89.3%to 99.3%,with relative standard deviations(RSD)in the range of 1.2%to 7.3%.The LOQs of the method were all 2.0μg/kg.[Conclusions]The method is simple and cheap with high efficiency and accuracy,which is suitable to analyze fenthion and its typeⅠmetabolites in cowpea in Hainan.This method will supply an effective technical support to supervise fenthion and its typeⅠmetabolites in cowpea.