基于超高效液相色谱-四极杆/静电场轨道阱高分辨质谱筛查茶叶中166种农药残留方法研究

Screening of 166 Pesticide Residues in Tea Based on Ultra High Performance Liquid Chromatography-Quadrupole/Electrostatic Field Orbitrap High Resolution Mass Spectrometry

建立了改良QuEChERS/超高效液相色谱-四极杆/静电场轨道阱高分辨质谱(QuEChERS/UHPLC-Q-Exactive Orbitrap MS)同时测定茶叶中166种农药残留的分析方法。样品采用改良QuEChERS技术进行前处理,以Full MS模式下的精确分子离子为定量离子,特征碎片离子与二级质谱信息定性,外标法定量。以绿茶和红茶作为基质验证方法的准确度和精密度。绿茶中15种农药在4~200μg/L范围内线性关系良好,其余151种农药在2~200μg/L范围内线性关系良好;红茶中所有农药在2~200μg/L范围内线性关系良好;相关系数(r)均大于0.99。绿茶与红茶中基质效应分别为-56%~63%和-19%~110%。在4个加标水平下,绿茶、红茶中116种农药的回收率均在70%~130%之间;绿茶和红茶中分别有99%、87%的农药相对标准偏差(RSD)小于20%。定量下限(LOQ)为10~25μg/kg。应用建立的方法分析20份实际茶叶样品(14份绿茶,6份红茶)的农药残留情况,绿茶、红茶样品中各检出9种农药,残留量均低于国家标准最大残留限量。该方法为茶叶中农药残留的高通量筛查提供了参考。

An ultra high performance liquid chromatography-quadrupole/electrostatic field orbitrap high resolution mass spectrometric(UHPLC-Q-Exactive Orbitrap MS)method was established for the simultaneous determination of 166 pesticide residues in tea.The samples were pretreated by modified QuEChERS technology.In Full MS mode,the accurate molecular ion was employed as quantitative ion.The characteristic fragment ions and secondary mass spectrometry informations were used for qualitative analysis,and the external standard method was adopted for quantification.The accuracy and precision of the method were verified by taking green tea and black tea as sample matrices.Fif⁃teen pesticides in green tea had good linear relationships in the range of 4-200μg/L,and the remain⁃ing 151 pesticides had good linear relationships in the range of 2-200μg/L.All pesticides in black tea had good linear relationships in the range of 2-200μg/L,and the correlation coefficients(r)were all greater than 0.99.Matrix effects of green tea and black tea were-56%-63%and-19%-110%,re⁃spectively.The recoveries of 116 pesticides in both green tea and black tea were all in the range of 70%-130%at four spiked levels.The relative standard deviations(RSDs)of 99%and 87%pesticides in green tea and black tea were both less than 20%.The limits of quantitation(LOQs)were 10-25μg/kg.The method was applied to analyze the pesticide residues in 20 real tea samples(14 green teas and 6 black teas).Nine pesticides were detected in green tea and black tea samples,and the resi⁃dues were lower than the national standard maximum residue limits.This method provides a reference for high-throughput screening and detection of pesticide residues in tea.