羟基化多壁碳纳米管分散固相萃取-气相色谱-质谱法测定茶叶中21种有机磷农药

建立了用羟基化多壁碳纳米管(MWCNTs-OH)、N-丙基乙二胺键合固相吸附剂(PSA)和MgSO₄作为吸附剂的改进QuEChERS-气相色谱-质谱快速检测茶叶中21种有机磷农药的方法。茶叶中残留的农药经正己烷-丙酮(2 : 1, v/v)混合溶剂提取,以MWCNTs-OH、PSA和MgSO₄去除杂质,离心、过滤后经气相色谱-电子轰击源质谱测定,外标法定量。结果表明,目标化合物在0.01~0.50 mg/kg范围内的线性关系良好。空白茶叶样品在低、中、高3个添加水平下的平均回收率为81.5%~109.4%,相对标准偏差(n=5)为2.3%~10.6%,定量限为0.001~0.040 mg/kg。该方法操作简单、快速、灵敏、成本低,能满足茶叶中常见有机磷农药残留的检测要求。

Determination of 21 organophosphorus pesticides in tea by gas chromatography-mass spectrometry coupled with hydroxylated multi-walled carbon nanotubes based on dispersive solid-phase extraction

A rapid determination method of 21 organophosphorus pesticides in tea was developed by QuEChERS method using modified multi-walled carbon nanotubes (MWCNTs-OH), primary-secondary amine (PSA) and MgSO₄ coupled with gas chromatography-mass spectrometry. The pesticide residues in tea were extracted with a hexane-acetone (2 : 1, v/v) mixture, and cleaned up by dispersive solid-phase extraction using MWCNTs-OH and primary-secondary amine (PSA) as the sorbents. After centrifugation and filtration, the target compounds were analyzed by gas chromatography-mass spectrometry and quantified by the external standard method. Under the optimized conditions, good linearities were obtained in the range of 0.01-0.50 mg/kg. The average recoveries were in the range of 81.5%-109.4% at three spiked levels, with relative standard deviations (RSDs, n=5) of 2.3%-10.6%. The limits of quantification were 0.001-0.040 mg/kg. This method is simple, fast, sensitive, cheap, and can meet the requirements of the rapid detection of organophosphorus pesticides in tea.