应用分析保护剂补偿基质效应与气相色谱-质谱快速检测果蔬中农药多残留

Rapid Determination of 45 Pesticide Residues in Fruits and Vegetables by Dispersive PSA Cleanup and Gas Chromatography-Mass Spectrometry with Correction of Matrix Effects

评价了在分析过程中添加分析保护剂（3-乙氧基-1，2-丙二醇和D-山梨醇）对农残分析定量结果可靠性以及补偿基质效应的影响，表明对大多数农药（尤其是乙酰甲胺磷、氧乐果、甲胺磷、对氧磷）能显著补偿由基质增强效应造成的定量误差，并降低了检出限；同时发现op＇-DDT和pp＇-DDT显示有基质减弱效应，保护剂对其没有补偿作用。建立了果蔬中45种农药的选择离子监测模式下气相色谱-质谱检测方法。样品前处理采用乙腈提取、N-丙基乙二胺键合固相吸附剂分散净化、气质联用（SIM方式）检测。该方法在0．05～5．00mg／L范围线性关系良好，相关系数在0．99以上，检出限在0．0001—0．005mg／kg之间（溴氰菊酯为0．04mg／kg）。在葡萄中添加0．5mg／kg浓度系列的各种农药，其添加回收率范围在73％～111％，相对标准偏差小于11．6％。

This study demonstrated that applying analyte protectants could provide a more accurate quantitation and compensate ＂matrix-induced chromatographic response enhancement＂ in gas chromatography -mass spectrometry（ GC -MS） analysis, thus increasing analytical reliability. The matrix-induced error for most pesticides has been alleviated, especially for acephate, omethoate, and methamidophos, etc. , by GC analyte protectants. However, it can not be compensated for o,p＇-DDT and p,p＇- DDT which show certain matrix suppression effects. An analytical method was developed for rapid determination of 45 pesticides and their isomers in fruits and vegetables by GC - MS in the selective ion monitoring mode with the aid of analyte protectant （3-ethoxy-1,2-propanediol and D-sorbitol）. Pesticides were extracted from samples with acetonitrile and the extracts were cleaned up using dispersed primary - secondary amine （PSA） absorbent. Good linear and low limits of detection were obtained, the linear range are between 0. 05 - 5.00 mg/L, correlation coefficients are better than 0. 99, and the detection limits are between 0. 000 1 - 0. 005 mg/kg except for deltamethrin （ LOD 0. 04 mg/kg）. All compounds have mean recoveries of 73%- 11196 （0. 5 mg/kg level） and the relative standard deviation values are all less than 11.6% except for chlorothalonil.