固相萃取-气相色谱质谱法测定茶叶中11种农药残留量

Determination of 11 kinds of pesticide residues in tea by solid phase extraction-gas chromatography-mass spectrometry

目的建立固相萃取-气相色谱质谱联用法测定茶叶中11种农药残留量的分析方法。方法茶叶样品中的农药残留经丙酮提取,无水硫酸镁除水,采用Carbon/NH_2固相萃取柱在线净化与富集,DB-17MS毛细管柱分离检测,多离子反应模式,外标法定量。结果在20～200 mg/L的浓度范围, 11种农药残留均与其对应的峰面积呈线性关系,方法的检出限(S/N=3)在0.001～0.018 mg/kg之间。以空白样品为基体进行加标回收实验,所得回收率在72.0%～93.2%之间,测定值的相对标准偏差(n=6)在2.35%～6.34%之间。结论该方法准确度较高、稳定性较好、检出限低,适用于茶叶样品中有机磷、氨基甲酸酯、拟除虫菊酯和杀菌剂等多组分农药残留量的同时测定。

Objective To establish a method for the determination of 11 kinds of pesticide residues in tea by solid phase extraction-gas chromatography-mass spectrometry. Methods The pesticide residues in the tea were extracted with acetone, and the water was removed by anhydrous magnesium sulfate. The carbon/NH2 solid phase extraction column was used for on-line purification and enrichment, DB-17 MS capillary column for separation detection, with multi-ion reaction mode, and external standard method for quantity. Results In the concentration range of 20~200 mg/L, the 11 kinds of pesticide residues showed a linear relationship with their corresponding peak areas. The detection limit(S/N=3) of the method was between 0.001 mg/kg and 0.018 mg/kg. The blank sample was used as the matrix to carry out the spike recovery test. The recoveries were between 72.0% and 93.2%, and the relative standard deviations of the measured values(n=6) were between 2.35% and 6.34%. Conclusion This method has high accuracy and stability, and has low detection limit, which is suitable for simultaneous determination of multi-component pesticide residues such as organophosphorus, carbamate, pyrethroid and bactericide in tea samples.