QuEChERS分散固相萃取—气相色谱—负化学电离质谱法测定植物油中氟虫腈及其代谢物残留

Determination of Fipronil and Its Metabolite Residues in Vegetable Oil by QuEChERS dSPE EMR Lipid-Gas Chromatography Negative Chemical Ionization Mass Spectrometry

建立了基于QuEChERS分散固相萃取(dSPE)气相色谱-负化学电离质谱(GC-NCI/MS)测定植物油中氟虫腈及其代谢物残留的分析方法。样品经乙腈提取,QuEChERS dSPE EMR-Lipid萃取净化,分取净化液浓缩至近干,正己烷复溶,GC-NCI/MS检测。GC-NCI/MS分析方法用氦气作为载气,流速设为1 mL/min;反应气为甲烷,气体流量40%;采用Agilent DB-5MS色谱柱进行分离,升温程序:初始温度设置40℃,保持1 min,以30℃/min升温至200℃,然后以15℃/min升到300℃,维持3 min,选择离子监测(SIM)检测,基质匹配外标法定量。在玉米油、橄榄油、菜籽油、大豆油、花生油这5种基质中,氟虫腈及其代谢物在质量浓度0.5~25 ng/mL范围与其对应的峰面积之间线性关系良好,相关系数R^(2)均大于0.994,在0.002、0.004和0.02 mg/kg 3个添加水平下,氟虫腈及其代谢物的平均回收率在95%~115%之间,相对标准偏差在0.36%~8.40%之间。方法灵敏度、准确度和精密度均符合氟虫腈及其代谢物残留检测的要求。

To establish an analytical method for the determination of fipronil and its metabolite residues in vegetable oil by QuEChERS dSPE EMR Lipid-gas chromatography negative chemical ionization mass spectrometry.The sample was extracted twice with 10 mL of acetonitrile(saturated with n-hexane)and purified by QuEChERS dSPE EMR Lipid.The purified solution was separated and concentrated,re-dissolved in 1 mL n-hexane and directly tested on the machine through the membrane.The GC-NCI/MS method took helium as the carrier gas and the flow rate was 1 mL/min;The reaction gas was methane,and the gas flow was 40%;Agilent DB-5MS chromatographic column was used for separation.Temperature programmed:the initial temperature was 40℃,maintained for 1 min,increased to 200℃at 30℃/min,then increased to 300℃at 15℃/min,maintained for 3 min,negative chemical ionization source(NCI),selected ion monitoring(SIM)for detection,and matrix matching external standard method for quantification.In 5 substrates(olive oil,soybean oil,corn oil,rapeseed oil,peanut oil),there was a good linear relationship between the mass concentration of fipronil and its metabolite residues and its corresponding peak area at 0.5-25 ng/mL.R^(2)was all greater than 0.994.At the 3 levels of 0.002,0.004 and 0.02 mg/kg,the average recovery of fipronil and its metabolite residues was between 95%and 115%,and the relative standard deviation was between 0.36%and 8.4%.The accuracy,precision and sensitivity of the method meet the requirements of fipronil and its metabolite residues detection.