固相萃取-气相色谱法同时检测茶叶中多种农药和多氯联苯残留

Multiresidue Determination of Pesticides and Polychlorinated Biphenyls in Tea by Solid-phase Extraction and Gas Chromatography

建立茶叶中21种有机氯、拟除虫菊酯类农药和多氯联苯(polychlorinated biphenyls,PCBs)残留固相萃取(solid-phase extraction,SPE)-气相色谱分析方法。用正己烷-丙酮(1:1,V/V)提取,经Envi-Carb/NH2复合固相萃取柱净化,采用RTX-5毛细管柱分离,气相色谱-电子捕获检测器(gas chromatography-electron caputure detector,GC-ECD)检测。在0.02、0.05、0.3mg/kg三个添加水平,平均回收率为68.64%～125.62%,相对标准偏差(relativestandard deviation,RSD)为1.05%～12.78%,该方法的检测限(detection of limit,LOD)在0.0022～0.0129mg/kg之间,适用于茶叶试样中痕量残留的分析。

A solid-phase extraction and gas chromatographic method was established to simultaneously determine 21 organochlorines, pyrethroids and polychlorinated biphenyls （PCBs） in tea. Tea samples were extracted with hexane-acetone （1：1, V/V） in an ultrasonic bath and cleaned up on an Envi-Carb/NH2 SPE column. The analytes were separated on a RTX-5 capillary column and detected in 63Ni-ECD （electron capture detector）. The recoveries for the analytes were from 68.64% to 125.62% with a relative standard deviation （RSD） from 1.05% to 12.78% at the spike levels of 0.02, 0.05 mg/kg and 0.3 mg/kg. The limits of detection （LOD） of the method ranged from 0.0022 to 0.0129 mg/kg. In conclusion, this method can be suitable for the determination of organic contaminants in tea samples.