固相萃取–气相色谱–串联质谱法测定茶叶中9种农药残留量

建立固相萃取净化–气相色谱–串联质谱法同时测定茶叶中9种农药残留量的方法。茶叶样品用乙腈均质提取,提取液经固相萃取净化处理后,采用DB–5MS毛细管色谱柱分离,在多反应监测模式下测定,外标法定量。9种农药组分的质量浓度在0.01~0.50 mg/L范围内与其色谱峰面积呈良好线性,相关系数r~2大于0.998,方法测定下限(10 S/N)为0.002~0.01 mg/kg。以空白绿茶、红茶、普洱茶和乌龙茶为基体,在0.05,0.1,0.2 mg/kg 3个添加水平进行加标回收试验,加标回收率在73.6%~99.7%之间,相对标准偏差为4.2%~8.7%(n=6)。该法操作简便、快速,适用于茶叶中多种农药残留的测定。

Determination of Nine Pesticides Residues in Tea by Solid Phase Extraction and Gas Chromatography-Tandem Mass Spectrometry

A gas chromatography–tandem mass spectrometry(GC–MS–MS) method was developed for simultaneous determination of nine pesticides residues in tea. The samples were extracted with acetonitrile and cleaned up using solid phase extraction. After separated on DB–5MS capillary column,the target analytes were detected by GC–MS–MS under the multi reaction monitoring mode and quantified by the external standard method. The correlation coefficents (r2) of nine pesticides were more than 0.998 obtained within the concentration range of 0.01 to 0.5 mg/L. The limits of quantitation varied from 0.002 to 0.01 mg/kg. At three spiked levels of 0.05, 0.1, 0.2 mg/kg in blank tea, the average recoveries ranged from 73.6%to 99.7%and the relative standard deviations were from 4.2%to 8.7%(n=6). The method is easy to operate and fast, and it is suitbale for determination of pesticides residues in tea.