微柱固相萃取结合气相色谱-质谱法分析茶叶中有机氯农药

Solid-phase extraction using mini-column for the determination of organochlorine pesticides in tea by gas chromatography-mass spectrometry

研制了碳纳米管微柱,建立了测定有机氯类农药的微柱固相萃取气相色谱-质谱法。样品泵入多壁碳纳米管微柱,8种有机氯类农药吸附保留到微柱,引入甲醇洗脱,气质联用选择离子监测方式检测洗脱液中有机氯类农药。考察了影响微柱固相萃取有机氯类农药的各种因素,包括样品流速、样品体积、洗脱剂种类、洗脱剂体积和碳纳米用量等。建立的方法适用于茶叶水提液中8种有机氯类农药分析,检出限0.015～0.25μg/kg。加标样品回收率74.5%～107.2%,相对标准偏差小于12%。

A method of determination of organochlorine pesticides（OCPs） by gas chromatography-mass spectrometry（GC-MS） was developed based on solid-phase extraction using self-made mini-column filled with multi-walled carbon nanotubes（MWCNTs）.The preconcentration and clean-up of OCPs was carried out based on the adsorption retention of analytes on the MWCNTs via pumping the sample into the mini-column system.Methanol was introduced to elute the retained analytes for GC-MS detection using selected ion monitoring（SIM） mode.Important influence factors were studied in detail,such as sample flow rate,sample volume,eluent type,eluent volume and carbon nanotubes mass.The developed method was feasible to determine OCPs in tea with the limit of detection in the range of 0.015～0.25 μg/kg.Recoveries of the spiked tea sample were in the range of 76.5%～107.2% with relative standard deviations of no more than 12%.