QuEChERS-在线凝胶色谱-气相色谱-质谱法测定大米、黍子和小麦中34种农药残留

采用QuEChERS方法结合在线凝胶色谱-气相色谱-质谱（GPC-GC-MS）系统，建立了大米、黍子和小麦中34种中高毒农药的快速筛查方法。研究了称样量、萃取剂、净化吸附剂种类对大米样品提取净化效果的影响并考察了基质效应和分析保护剂的使用效果，采用选择离子监测（SIM）模式，外标法定量。结果表明，34种农药在大米、黍子和小麦中的检出限分别为0.0281~5.30、0.0282~4.82、0.0273~5.13 μg/kg；在0.05 μg/g添加水平的平均回收率分别为94.5%~117.1%、83.1%~121.7%、93.1%~120.2%；相对标准偏差（RSD，n=6）分别为2.6%~14.5%、3.4%~15.1%、3.5%~15.2%。该方法消耗试剂少，分析成本低，符合绿色化学的理念，具有操作便捷、快速、通用性强等特点，适用于大米、黍子和小麦中34种农药残留的快速筛查与检测。

Determination of 34 pesticide residues in rice,proso millet and wheat with QuEChERS-on line gel permeation chromatography-gas chromatography-mass spectrometry

A method for the simultaneous determination of 34 pesticides in rice, proso millet and wheat by QuEChERS coupled with on line gel permeation chromatography-gas chromatography-mass spectrometry (GPC-GC-MS) was developed. The effects of the sample weight, extraction solvent, sorbent for purification were investigated. The matrix effect and the usefulness of analyte protectant were also studied. The identification and quantification were performed by GPC-GC-MS in selected ion monitoring (SIM) mode and external standard method. The calibration curves of the 34 pesticides showed good linearity in the range of 0.0125-0.2 mg/L with the correlation coefficients (r²) between 0.968 and 0.999. The average recoveries were 94.5%-117.1%, 83.1%-121.7% and 93.1%-120.2% with the relative standard deviations (RSDs, n=6) no more than 14.5%, 15.1% and 15.2% in rice, proso millet and wheat samples, respectively. The LODs of this method were 0.0281-5.31, 0.0282-4.82 and 0.0273-5.13 μg/kg (S/N=3) for rice, proso millet and wheat samples, respectively. The low cost and less consumption of reagents of this method are in accordance with the concept of green chemistry. The convenient operation and versatility of this method are suitable for the fast screening and detection of the 34 pesticide residues in rice, proso millet and wheat.