QuEChERS-气相色谱-串联质谱法测定油麦菜中农药多残留的基质效应

目的建立一种QuEChERS-气相色谱-串联质谱法(gas chrom atography-tandem mass spectrometry,GC-MS/MS)测定油麦菜中64种农药多残留基质效应的分析方法。方法样品经乙腈提取, N-丙基乙二胺(PSA)净化,配制基质标准点与溶剂标准点进行峰面积对比来评价基质效应。结果油麦菜基质对18.8%的农药多残留项目不表现基质效应,对37.5%的项目有强基质效应;当基质液稀释至50倍后,对81.3%的农药多残留项目不表现出基质效应;稀释至100倍后,有氟胺氰菊酯、氯氟氰菊酯和水胺硫磷3种处于中等基质效应。结论在使用气相色谱-串联质谱法测定油麦菜中农药多残留含量的过程中,需要通过稀释来准确定量时,要注化合物在不同稀释比例的基质下所受到的基质效应的影响。该方法快速、简单,适用于蔬菜水果中农药多残留基质效应的测定和评估。

Determination of matrix effects of pesticide multi-residues in lettuces by QuEChERS-gas chromatography-tandem mass spectrometry

Objective To establish a method for the determination of matrix effects of 64 pesticides multi-residue in lettuce by QuEChERS-gas chromatography-tandem mass spectrometry (GC-MS/MS). Methods Samples were extracted with acetonitrile, and purified by primary secondary amine (PSA). The matrix effects were evaluated by comparing the peak areas of the matrix standard and the solvent standard. Results The lettuce substrate did not exhibit a matrix effect on 18.8% of pesticide multi-residue projects, and had a strong matrix effect on 37.5% of the projects. When the substrate solution was diluted to 50 times, it did not exhibit a matrix effect on the 81.3% pesticide multi-residue projects. And the tau-fluvalinate, cyhalothrin and isocarbophos still showed a moderate matrix effect even when the matrix solution was diluted with 100 times. Conclusion In the process of determining the multi-residue content of pesticides in lettuce by gas chromatography-tandem mass spectrometry, it is necessary to accurately quantify by dilution, and to influence the matrix effect of the compound under different dilution ratios. This method is rapid and simple, which is suitable for determination and evaluation the matrix effects in vegetables and fruits.