普洱茶中有机磷类农药残留的测定

为建立气相色谱技术同时测定茶叶中多种有机磷农药残留的方法，并用该方法检测来自云南省5 个普洱茶主产区的30 个普洱茶样品中的有机磷农药残留量，为其安全性评价提供科学数据。样品以乙酸乙酯为提取剂经超声波萃取，提取液用活性炭小柱净化，采用气相色谱火焰光度检测器检测，外标法定量。该方法在3 个添加水平下，9 种组分的平均回收率为71.1%～113.8%，相对标准偏差为0.9%～13.3%。方法的检测限为1.0～2.5μg/kg。普洱茶样品检出的农药有敌敌畏、乙酰甲胺磷、乐果、杀螟硫磷、马拉硫磷、喹硫磷、三唑磷，其中杀螟硫磷和乐果的检出率较高，但含量均低于欧盟限量标准。从茶叶中有机磷农药残留量来看，普洱茶具有较高的食用安全性。

GC with Flame Photometric Detection for the Simultaneous Determination of Organophosphorus Pesticide Multiple Residues in Pu-erh Tea

A method using gas chromatography (GC) with flame photometric detection was developed for the simultaneous determination of 9 organophosphorus pesticide multiple residues in tea matrices. A total of 30 Pu-erh tea samples from 5 producing areas in Yunnan province (half raw tea and half ripe tea, with 3 replicates for each area) were determined by the developed method in order to provide experimental data for safety assessment. Samples were extracted with ethyl acetate under the assistance of ultrasonic, followed by clean-up on an activated carbon cartridge. Quantification was achieved using external standard method. Mean recoveries for 9 analytes at 3 spike levels ranged from 71.1% to 113.8%, with a RSD between 0.9% and 13.3%. The developed method exhibited limits of detection ranging from 1.0 to 2.5μg/kg. Dichlorovos, acephate, dimethoate, fenitrothion, malathion, quintozene and triazophos were all detected in selected Pu-erh tea samples. Among them, the detection rates of fenitrothion and dimethoate were higher, but the contents were both lower than the EU limit standard. In terms of organophosphorus pesticide multiple residues in Pu-erh tea, it is safe for drinking.