FaPEx柱萃取净化结合GC-MS法同时测定绿茶中20种农药残留

Simultaneous determination of 20 pesticide residues in green tea by FaPEx column extraction andpurification combined with GC-MS

该研究建立了FaPEx柱萃取净化结合气相色谱-质谱(GC-MS)检测绿茶中20种农药残留量的方法。样品粉碎后加水浸泡30 min,采用10 mL 1%醋酸-乙腈提取,经FaPEx柱萃取净化后浓缩至近干,加入1 mL乙酸乙酯复溶,经DB-5MS UI色谱柱(30 m×0.25 mm×0.25μm)分离,采用选择离子监测(SIM)模式,内标法进行定量。结果表明,20种农药在质量浓度0.01~0.50μg/mL范围内线性关系良好,相关系数R2均>0.99,在0.05 mg/kg、0.10 mg/kg、0.50 mg/kg三个质量浓度添加水平下,平均加标回收率为71.8%~118.2%,精密度试验结果的相对标准偏差(RSD)为1.63%~11.50%,方法检出限(LOD)为0.006~0.015 mg/kg,方法定量限(LOQ)为0.020~0.050 mg/kg。该方法准确度及精密度好,稳定性高,适用于绿茶中20种农药残留量的测定。

A method for the determination of 20 pesticide residues in green tea by column extraction and purification combined with GC-MS was established.The samples were crushed and soaked in water for 30 min,then extracted with 10 ml 1%acetonitrile acetate,extracted and purified by FaPEx column,concentrated to nearly dry,redissolved with 1 ml ethyl acetate,separated by DB-5MS UI chromatographic column(30 m×0.25 mm×0.25μm),detected by selected ion monitoring(SIM)mode,and quantified by internal standard method.The results showed that the linear range of 20 pesticides was good in the range of 0.01-0.50μg/ml,and the correlation coefficients R2 were all greater than 0.99.At the 3 addition levels of mass concentration 0.05 mg/kg,0.10 mg/kg and 0.50 mg/kg,the average recoveries were 71.8%-118.2%,the relative standard deviation(RSD)of precision tests results were 1.63%-11.50%,the limits of detection(LOD)were 0.006-0.015 mg/kg,and the limits of quantification(LOQ)were 0.020-0.050 mg/kg.This method had good accuracy,precision and stability,and it was suitable for the determination of 20 pesticide residues in green tea.