分散固相萃取—气相色谱—串联质谱法测定食用菌中24种农药残留

Determination of 24 pesticide residues in fresh edible fungiby dispersive solid phase extraction-gas chromatography coupled with tandem mass spectrometry

目的:建立同时测定新鲜食用菌中的24种农药残留的气相色谱—串联质谱法。方法:样品匀浆后,加入水、乙腈、盐,水平振摇提取,高速离心后去上清液氮气浓缩,乙酸乙酯定容,GC-MS/MS测定。使用电子轰击离子源(EI)进行电离,多反应监测(MRM)模式对目标物碎片进行采集,内标法定量分析。结果:24种农药的内标曲线在一定质量浓度范围内线性良好,相关系数R 2均在0.9986以上,方法检出限(LOD)为2.0~3.0μg/kg,方法定量限(LOQ)为5.0~10.0μg/kg。在1,2,5倍定量限加标水平下,24种农药加标回收率为76.4%~101.0%,相对标准偏差(RSD)为1.79%~8.98%。结论:该方法具有操作简单、快捷、回收率好、灵敏度高、重现性好等优点,适用于新鲜食用菌中24种农药残留的测定。

Objective:A gas chromatography-tandem mass spectrometry method was established for the simultaneous determination of 24 pesticide residues in fresh edible fungi.Methods:Samples were homogenized and then shaken horizontally for extraction with water,acetonitrile and salt.After high-speed centrifugation,the supernatant was removed and concentrated with nitrogen then reconstituted with ethyl acetate and finally determined by GC-MS/MS.Electron impact ionization(EI)was used for ionization,multiple reaction monitoring(MRM)mode was used to collect target fragments by multiple reaction monitoring(MRM)mode and internal standard method was used for quantitative analysis.Results:24 pesticides showed good linearities in their respective concentration ranges with correlation coefficient(R 2)that were both greater than 0.9986.The limit of detection(LOD)and quantification(LOQ)of the method were in the ranges of 2.0~3.0μg/kg and 5.0~10.0μg/kg,respectively.Average recovery rates of 24 pesticides ranged from 76.4%to 101%with the relative standard deviation(RSD)being 1.79%to 8.98%.Conclusion:The method was simple to operate,rapid,good recovery,high sensitivity and good reproducibility and suitable for the determination of 24 pesticide residues in fresh edible fungi.