QuEChERS结合实时直接分析串联质谱法检测茶叶中的农药残留

Determination of pesticide residues in tea by QuEChERS combined with direct analysis in real time-tandem mass spectrometry

中文关键词:  茶叶  农药残留  QuEChERS  实时直接分析串联质谱法

英文关键词:tea  pesticide residue  QuEChERS  direct analysis in real time-tandem mass spectrometry

中文摘要:

      目的 建立实时直接分析串联质谱法(direct analysis in real time-tandem mass spectrometry, DART-MS/MS)检测茶叶中烯酰吗啉、噻虫嗪、吡唑醚菌酯、吡虫啉、灭多威、吡蚜酮、杀线威、仲丁威、啶虫脒等9种常见农药残留的分析方法。方法 样品采用QuEChERS方法进行前处理, 粉碎茶样通过乙腈提取, 采用无水MgSO4和NaCl盐析, N-丙基乙二胺(primary secondary amine, PSA)、C18和石墨化碳黑(graphitized carbon black, GCB)分散固相萃取净化, 用玻璃棒蘸取上清液经DART-MS/MS检测。结果 9种化合物在0.5～50 μg/L范围内线性关系良好, 相关系数(r2)均大于0.9, 9种农药在5、10和50 μg/kg添加水平的平均回收率为70.1%～109.8%, 相对标准偏差(relative standard deviation, RSD)为15.5%～22.4%, 9种农药的定量限均为 5 μg/kg。结论 该方法提取、净化环节简单、快速, 无需氮吹转溶; 上机检测环节无需色谱分离, 直接通过实时直接质谱分析, 大大节省了分析时间。该方法的建立为现有茶叶农药残留检测方法和标准提供了一种有益的补充。

英文摘要:

      Objective To establish a direct analysis in real time-tandem mass spectrometry (DART-MS/MS) method for the determination of dimethomorph, thiamethoxam, pyrazoxystrobin, imidacloprid, methomyl, pymetrozine, methomyl, fenbucarb and acetamiprid in tea. Methods The samples were pretreated by QuEChERS method. The tea samples were extracted by acetonitrile, salting out with anhydrous MgSO4 and NaCl, and purified by dispersing primary secondary amine (PSA), C18 and graphitized carbon black (GCB). The supernatant was dipped in glass rod and detected by DART-MS/MS. Results The average recoveries of the 9 pesticides at the levels of 5, 10 and 50 μg/kg were 70.1%?109.8%, and the relative standard deviations (RSDs) were 15.5%?22.4%. The limits of quantifications (LOQs) of the 9 pesticides were 5 μg/kg. Conclusion This method is simple, rapid and does not need nitrogen blowing for solubilization; the detection process does not need chromatographic separation, and can be directly analyzed by real-time direct mass spectrometry, which greatly saves the analysis time. This method provides a useful supplement for the existing methods and standards of pesticide residues in tea.