气相色谱-三重四极杆质谱法测定植物源性食品中20种拟除虫菊酯类农药残留

建立了气相色谱-三重四极杆质谱(GC-MS/MS)同时测定植物源性食品中20种拟除虫菊酯类农药残留量的方法。样品经丙酮-正己烷(1∶1,v/v)提取,活性炭小柱净化,外标法定量。目标物在0.005~1.0 mg/L范围内呈良好的线性相关,相关系数(r~2)均不小于0.990,方法的检出限(信噪比(S/N)3)均为2.0μg/kg,定量限(S/N10)均为5.0μg/kg。分别在11种基质中做低、中、高3个添加水平的加标回收试验,该方法的平均回收率为75.2%~107%,相对标准偏差(RSD,n=6)为3.08%~12.1%。该方法前处理步骤简便,特异性强,适用范围广,适用于植物源性食品中20种拟除虫菊酯类农药的筛查和确证。

Determination of 20 pyrethroid residues in vegetable foods by gas chromatography-tandem mass spectrometry

A method of gas chromatography-tandem mass spectrometry (GC-MS/MS) was developed for the simultaneous determination of 20 pyrethroid residues in vegetable foods. The samples were extracted by acetone-n-hexane (1:1, v/v), cleaned up by activated charcoal column and quantified by external standard method. The correlation coefficients (r²) of all the 20 pyrethroid pesticides in the range of 0.005-1.0 mg/L were not less than 0.990. The limits of detection (LODs) were 2.0 μ g/kg when signal/noise (S/N) > 3. The limits of quantification (LOQs) were 5.0 μ g/kg (S/N > 10). For recovery test, there were three levels (low, medium and high) spiked in 11 matrices. The average recoveries of the method were 75.2%-107% and the relative standard deviations (RSDs, n=6) were 3.08%-12.1%. The results demonstrated that the method is simple and has specific pretreatment steps. The method is suitable for the screening and confirmation of the 20 pyrethroid pesticides in vegetable foods.