磁固相萃取结合超高效液相色谱串联质谱法检测绿茶中19种有机磷农药残留

Determination of 19 Organophosphorus Pesticide Residues in Green Tea by Magnetic Solid Phase Extraction Combined with Ultra High Performance Liquid Chromatography Tandem Mass Spectrometry

本文采用化学共沉淀法合成磁性石墨烯(Fe_(3)O_(4)@G),并将其作为一种磁固相萃取剂用于绿茶中有机磷农药的萃取富集,结合超高效液相色谱串联质谱技术,建立同时检测绿茶中19种有机磷农药残留的分析方法。本实验选择吸附剂用量为40 mg,萃取时间20 min,样品溶液pH为7,3.0 mL丙酮解吸,氯化钠用量为4 g。结果表明,在5~500μg/L范围内,线性相关系数大于0.999,制备的Fe_(3)O_(4)@G材料具有良好的稳定性和可重复利用性。检出限(LOD)在5.0~6.0μg/kg,定量限(LOQ)在15.0~20.0μg/kg。当样品加标水平为20.0、40.0、200.0μg/kg时,回收率在61.2%~94.9%之间,相对标准偏差(RSD,n=6)在2.6%~10.2%之间。本方法适用范围广,前处理易操控,有机溶剂用量少,经济,安全,材料可重复使用,该磁分散固相萃取技术在茶叶中农药的富集分离有很好的应用前景。

Magnetic graphene(Fe_(3)O_(4)@G)was synthesized as a magnetic solid phase extractor for the extraction and enrichment of organophosphorus pesticides in green tea by chemical coprecipitation method.Based on this,ultra high performance liquid chromatography tandem mass spectrometry method was developed for the determination of 19 organophosphorus pesticide residues in green tea.40 mg adsorbent and 4 g sodium chloride were used in this experiment with the pH of sample solution at 7 for 20 min extraction time,3.0 mL acetone desorption.The result showed that the prepared Fe_(3)O_(4)@G material had good stability and reusability with the linear correlation coefficients greater than 0.999 in the range of 5~500μg/L.The limits of detection(LOD)and the limits of quantitation(LOQ)were 5.0~6.0μg/kg and 15.0~20.0μg/kg,respectively.The recoveries were between 61.2%and 94.9%with the relative standard deviations(RSD,n=6)in the range of 2.6%~10.2%when the samples were labeled at 20.0,40.0 and 200.0μg/kg.This method was safe and economy with a wide application range,easier control of pretreatment,less amount of organic solvent and reusable materials,which has a good application prospect in the enrichment and separation of pesticides in tea by the magnetic dispersion solid phase extraction technology.