采用气相色谱-串联质谱法测定食用油中27种农药的残留量。样品中加入环己烷-乙酸乙酯(1+1)溶液,漩涡振荡1 min,提取液经凝胶色谱净化后,于50 ℃水浴中浓缩至近干,用正己烷定容至1.0 mL。采用HP-5MS色谱柱分离,质谱分析中选用电子轰击离子源和选择反应监测模式。27种农药的峰面积与其质量浓度在10~500 μg·L-1范围内呈线性关系,检出限(3S/N)在1.3~8.0 μg·kg-1之间。在10,100,400 μg·kg-1等3个浓度水平进行加标回收试验,回收率在70.2%~108%之间,测定值的相对标准偏差(n=6)小于16%。

GC-MS/MS was applied to the determination of 27 pesticide residues in edible oil. The sample was extracted with a mixture of cyclohexane and ethyl acetate (1+1) by vortex oscillation for 1 min. The extract was purified by gel permeation chromatography (GPC), concentrated to be nearly dry in the water bath of 50 ℃ and diluted to 1.0 mL with n-hexane. The analytes were separated on a HP-5MS column. EI and SRM were adopted in MS analysis. Linear relationships were founed between peak areas and mass concentrations of the 27 pesticides in the range of 10-500 μg·L-1, with detection limits (3S/N) in the range of 1.3-8.0 μg·kg-1. Tests for recovery were made at 3 concentration levels of 10, 100, 400 μg·kg-1, giving recovery rates in the range of 70.2%-108% and RSDs (n=6) less than 16%.