测定茶叶中27种有机氯和拟除虫菊酯农药多组分残留气相色谱法

Determination of 27 organochlorine and pyrethroid pesticide multi-residues in teas by gas chromatography

为了更有效地对我国茶叶的质量和安全性进行监管,建立了一种快速测定茶叶中20种有机氯和7种拟除虫菊酯农药多残留的气相色谱法.试样中农药残留在超声波振荡条件下用乙腈提取,提取液经氮气流浓缩和Florisil固相萃取小柱净化,用气相色谱-电子捕获检测器测定,色谱柱为HP-5小口径石英毛细管柱(30 m×0.32 mm×0.25 μm).农药的添加水平在6.0～228 μg/kg范围时,在绿茶中的平均添加回收率为71.2%～115%,相对标准差为3.42%～18.9%;在花茶中的平均添加回收率为71.1%～121%,相对标准差为3.55%～19.2%.方法的检测限范围为0.12～6.0 μg/kg.该方法快速、灵敏、准确、成本低,能满足农药多残留快速扫描的分析要求.

To control the pesticide residues in tea, a rapid and sensitive method has been established for the determination of 27 organochlorine and pyrethroid pesticide multi-residues in teas. The pesticide residues in tea samples were extracted with acetonitrile and by ultrasonic, the extracts were concentrated with stream of nitrogen, cleaned up by Florisil solid phase extraction column, and then determined by gas chromatography with electron capture detector. The column used was HP-5 capillary column （30 m × 0.32 mm × 0.25 μm） . Twenty organochlorine and 7 pyrethroid pesticide multi-residues in teas were determined by this method. When pesticide residues in teas were at the 6.0- 228 μg/kg levels, the mean recoveries in green teas ranged from 71.2% to 115% with the relative standard deviation of 3.42% to 18.9%, and the mean recoveries in floscular tea ranged from 71.1% to 121% with the relative standard deviation of 3.55% to 19.2%. The limits of detection of this method, based on chromatograms of blank samples and pesticide standards, were estimated to be from O. 12 to 6.0 ttg/kg of the pesticides in tea. Therefore, the method can meet with the fast analysis of pesticide multi-residues in teas.