茶叶中多种农药残留测定方法研究

Research on Determination of Multi-pesticide Residues in Tea

采用气相色谱-串联质谱法同时测定了茶叶中多种农药残留。样品加水后用乙腈提取,采用GCB/PSA固相萃取柱净化,淋出液浓缩至近干后用正己烷-丙酮（9：1,V/V）溶液定容,气相色谱-串联质谱测定。结果表明目标农药添加于样品中质量浓度在0.050～0.500mg/kg（r〉0.9700）范围内与峰面积呈线性关系,检出限（3S/N）位在0.1～37.5ng/g之间。加入0.100和0.400mg/kg两个浓度水平的农药标准溶液,目标农药的回收率在66.5%～114.7%之间,相对标准偏差（n=5）均小于20%。

Gas chromatography-tandem mass spectrometry （GC-MS/MS） method was developed for simultaneous analysis of multi-pesticide residues in tea. The sample was extracted with acetonitrile after the procedure of water addition; GCB/PSA solid-phase extraction （SPE） column was employed during clean-up step.The eluate was evaporated to near dryness and diluted with mixture of n-hexane and acetone （9：1,V/V）,and then determined with a MS/MS detector based on MRM.Linear relationships between values of peak area,and mass concentration of the targeted pesticides were obtained in the range of 0.050-0.500 mg/L （r〉0.9700） and the detection limits （3S/N） of this method were 0.1-37.Sng/g.When the spiked levels were 0.100 and 0.400mg/kg,the average recoveries ranged from 66.5 % to 114.7 % with RSDs （n=5） 〈20%.