應用多孔性矽藻土管柱及液相層析串聯質譜儀分析蔬果中81種農藥及代謝物   全文下載

Analysis of 81 Pesticides and Metabolite Residues in Fruits and Vegetables by Diatomaceous Earth Column Extraction and LC/MS/MS Determination

本研究建立了以液相層析串聯質譜儀，結合電灑法離子化，進行蔬果中81 種農藥及代謝物之多重殘留方析方法。檢體以丙酮進行萃取，運用多孔性矽藻土（macroporous diatomaceous earth, MDE）管柱取代分液漏斗進行液/ 液分配萃取，並以乙酸乙酯作為沖提溶劑。利用MDE 管柱進行前處理，相當簡單、快速而環保，可大幅減少檢體前處理時間及有機溶媒之使用量，且無檢液乳化問題。81 種分析物包括殺蟲劑、殺?劑、殺菌劑、殺草劑、植物生長調節劑及4 個農藥代謝物，屬於不同化學結構群組，可於25 分鐘內完成LC/MS/MS 分析，係以Atlantis T3 層析管柱配合梯度沖提進行分離。串聯質譜之數據擇取方法採多重反應偵測（multiple reaction monitoring, MRM）模式，每種農藥或代謝物以2 組MRM 離子片斷進行偵測，以獲得高感度及高選擇性之同步定性及定量分析結果，總計162 個MRM transitions 。運用標準品添加法去除基質效應以獲得精準定量結果。於小白菜、葡萄及柑橘中添加低濃度（0.05 或0.1 ppm）及高濃度（0.5 ppm）農藥，三重複結果顯示回收率及重複性良好。多數農藥之回收率界於70-120%，變異係數則皆小於25%。本研究建立之LC/MS/MS 分析方法與傳統之氣相層析或液相層析方法比較，其花費時間較短且具更高靈敏度，適用於日常蔬果農藥殘留監測。"

A multi-residue method for determining 81 pesticides and metabolite residues in vegetables and fruits by liquid chromatography/ tandem mass spectrometry (LC/MS/MS) with electrospray ionization was developed. Pesticide residues were extracted from samples with acetone. Macroporous diatomaceous earth column was used instead of the separatory funnel for liquid/liquid extraction. Ethyl acetate was used as eluting solvent for diatomaceous earth column. This sample preparation technique by diatomaceous earth column was easy, fast and environment-friendly. It can reduce the sample preparation time and solvent consumption as well as eliminate the emulsion problem. Eighty-one analytes of different chemical families of insecticides, acaricides, fungicides, herbicides, plant growth regulators and 4 pesticide metabolites were determined in a single 25 min LC/MS/MS run. The pesticides were separated on an Atlantis T3 column using a gradient elution. Data acquisition under MS/MS for every pesticide or metabolite was achieved by applying multiple reaction monitoring (MRM) of two fragment ion transitions to provide high sensitivity and selectivity for both quantification and confirmation. A total of 162 MRM transitions were monitored. The standard addition was employed to compensate for the matrix effects to achieve the maximum accuracy of the LC/MS/MS method. Vegetable (bok choy) and fruit samples (grape or orange) were fortified with pesticides of low (0.05 or 0.1 ppm) and high (0.5 ppm) levels, and the triplicate results showed satisfactory recoveries and repeatability. The recoveries for most pesticides ranged from 70 to 120% and the coefficients of variation of all pesticides were below 25% in all matrices. The developed method, compared with traditional GC or LC method, showed less time-consumption and higher sensitivity. The proposed method is considered satisfactory for routine monitoring of pesticide residues in fruits and vegetables.