使用大氣壓化學游離法結合液相層析串聯式質譜儀檢測玉米及黃豆中的中低極性農藥

Abstract

人類在農業持續過度濫用農藥，各種農藥和有機污染物由於其生物累積性和高毒性，對環境與非目標生物體造成嚴重傷害，因此農藥殘留問題不容忽視。本實驗以液相層析串聯式質譜儀搭配大氣壓化學法進行游離 (LC-APCI-MS/MS)，選擇衛福部公告方法適用於GC-EI-MS/MS檢測，危害度高且可使用APCI正電模式游離的12項農藥作為目標分析物，並將開發的方法運用在玉米及乾燥黃豆的農藥檢測。過程針對所選樣品優化QuEChERS前處理方法，移動相使用甲醇及水，皆添加0.2%甲酸及5 mM甲酸銨，選擇C18管柱作為固定相，成功以逆向層析梯度，在12 min內分離12項農藥，並以MRM掃描模式進行偵測與定量。基質匹配校正曲線線性範圍落在5 – 200 ng/mL，準確度介於87.48 – 116.82%，精密度在0.32 – 17.20%之間，偵測極限與定量極限的範圍分別為1 – 5 ng/mL與5 – 10 ng/mL，線性回歸 (R平方) 大於0.995。透過比較前添加與後添加農藥標準品，得到優化後的QuEChERS萃取法回收率為 80.36 – 119.86%。Since humans are used to overusing pesticides in agriculture, pesticides and organic pollutants which are bioaccumulative and highly toxic cause serious damage to the environment and the metabolism of non-target organisms. Therefore, the problem of pesticide residues in agricultural products can not be ignored. In this study, liquid chromatography atmospheric pressure chemical ionization tandem mass spectrometry (LC-APCI-MS/MS) was applied to quantify the 12 pesticides which are originally analyzed by gas chromatography tandem mass spectrometry (GC-MS/MS) with electron ionization (EI), according to the regulation of the Taiwan Food and Drug Administration (TFDA). The developed method was further applied to the pesticide analysis in corn and soybean. In the process, the QuEChERS extraction method was optimized for the selected samples. The mobile phases were methanol and water with the addition of 0.2% formic acid and 5 mM ammonium formate. Twelve pesticides were successfully separated within 12 minutes using reverse phase chromatography. MRM MS analysis was applied for detection and quantification. The linear range of the matrix-matched calibration curves were 5 – 200 ng/mL. The accuracy was 87.48 – 117.20%, and the precision was 0.32 – 17.20%. The detection limit and quantification limit ranges were 1 – 5 ng/mL and 5 – 10 ng/mL respectively. The coefficient of determination (R squared) was greater than 0.995. By comparing pre-spiked and post-spiked pesticide standards, the recoveries of the optimized QuEChERS extraction method were 80.36 – 119.86%.