多壁碳纳米管磁性固相萃取气相色谱质谱法测定茶叶中的8种农药残留

Determination of 8 Pesticide Residues in Tea by Gas Chromatography-Mass Spectrometry with Magnetic Multi-Walled Carbon Nanotubes Solid Phase Extraction

建立了磁性固相萃取-气相色谱质谱法测定茶叶中8种农药的检测方法,利用乙腈对样品进行提取,使用磁性吸附剂MWCNTs-Fe3O4富集和净化茶叶初提液中的农药,气相色谱-质谱定量检测。对影响磁性固相萃取的条件进行了优化,主要包括萃取剂、吸附剂用量、吸附时间、洗脱剂、洗脱时间等。结果表明,8种农药在各自质量浓度范围内线性关系良好,相关系数均大于0.991,方法检出限为0.004~0.010 mg/kg,定量限为0.008~0.020 mg/kg。在0.02、0.05 mg/kg和0.10 mg/kg 3个添加水平下,8种农药平均回收率为72.1%~106.4%,相对标准偏差为3.1%~6.2%。该方法处理过程简便、快速、高效、准确,能够满足茶叶中多种农药残留的检测。

A method for the determination of 8 pesticides in tea by magnetic solid phase extraction-gas chromatography-mass spectrometry was established.Firstly,tea sample was extracted with acetonitrile,and then the extraction solvent was enriched and purified by magnetic adsorbent MWCNTs-Fe3O4.Pesticides were analyzed by GC-MS/MS.Several parameters were optimized,including extractant selection,the amount of MWCNTs-Fe3O4,adsorption time,eluent solvent selection and eluent time.Under the optimized conditions,the calibration curves for 8 pesticides showed good linearity in their own ranges with correlation coefficients higher than 0.991.The limits of detection and the limits of quantitation of pesticides were in the range of 0.004~0.010 mg/kg and 0.008~0.020 mg/kg,respectively.The average recoveries at spiked levels of 0.02,0.05,0.10 mg/kg ranged from 72.1%~106.4% with relative standard deviations between 3.1%~6.2%.The method was simple,fast,efficient and accurate,which could be applied to the pesticide residues in tea.