羟基化多壁碳纳米管分散固相萃取-气相色谱-质谱法r测定茶叶中21种有机磷农药

摘要

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.%A rapid determination method of 21 organophosphorus pesticides in tea was devel-oped by QuEChERS method using modified multi-walled carbon nanotubes( MWCNTs-OH ), primary-secondary amine(PSA)and MgSO4 coupled with gas chromatography-mass spectrome-try. 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.