气相色谱—质谱法测定茶叶中12种农药残留的方法

DETERMINATION OF 12 PESTICIDE RESIDUES IN TEA BY GC/MS

用气相色谱—质谱仪研究同时测定茶叶中12种农药残留的测定方法。分析样品经粉碎、浸泡,用丙酮—正己烷(1:4,V/V)提取,经活性炭柱和弗罗里硅土柱净化,乙醚—丙酮—正己烷(4:4:2,V/V/V)洗脱后,以环氧七氯为内标,GC/MS测定。经过对茶叶加标的回收实验,证实具有快速灵敏简便的优点,适用于多种农药残留分析。其平均回收率在75%—110%,变异系数下于21%,最低检测限为0.01—0.5mg/kg。

This paper describes a method for the determination of 12 pesticide residues in tea by capillary gas chromatography-mass spectrometry. It also can make confirmation and quantitation. The pesticides were extracted from the tea sample with a mixed solvent of acetone-hexane(1;4,V/V),cleaned up on active carbon and Florisil with ether-acetone-hexane(4;4;2,V/V/V) and determined by GC/MS,using heptachlor epoxike as internal standard. After the analysis of a tea sample which the pesticides at a level of MRL(maximum residue limit),double the MRL,fivefold the MRL,the average recoveries were 70%-110%, and the limit of determination was 0.01-0.5mg/kg. Good repeatability was obtained in all the cases with coefficients of variation lower than 21%. This method is simple, rapid and sensitive for pesticides residue analysis.