Non-target Rapid Screening Of Pesticide Residues In Tea Beverage

Dispersive liquid-liquid microextraction(DLLME)coupled with HPLC-Q-TOF/MS method was developed for detecting of 37 kinds of pesticide residues in tea beverage to optimize DLLME conditions.Then the method was applied to build a 779 kinds of pesticide residues screening method.The main research contents and results were as follows:1.A DLLME-HPLC-Q-TOF/MS method was developed to detect 37 kinds of pesticides residues in tea beverage,and pretreatment conditions,instrumental conditions and methodological investigation were explored.The best conditions and results were as follows:(1)The optimal pretreatment conditions: purification agent was 2 g primary secondary amine(PSA),extraction solvent was 200 ?L trichloromethane,dispersive solvent was 100 ?L of methanol,and shaking table time was 5 min.(2)The optimal instrument conditions: Liquid chromatography column was X-Bridge BEH C18,the mobile phase was acetonitrile-0.1% formic acid,the optimal declustering potential was 80 V,the optimal collision energy combination was 20?35?50 eV.(3)Results of methodological investigation: the recovery of 37 kinds of pesticides were 83.1%~96.8%,relative standard deviations were 0.88%~8.11%,the linear range of matrix calibration curves were 0.08-16 ?g/kg,the correlation coefficient were over 0.9973.The limit of detection range were 0.001~0.092 ?g/kg,and limit of quantitative were 0.003~0.307 ?g/kg.2.A non-target rapid screening method for detecting 779 kinds of pesticide residues in tea beverage by dispersive solid phase extraction-DLLME-HPLC-Q-TOF/MS was established.The acquired data was compared with the library with the accurate mass,isotopic distribution,fragmentation information to screen 779 kinds of pesticide residues in tea beverage without any reference standards in one injection.3.Five unknown pesticides were used to evaluate the accuracy of the screening method.The result showed that the screening accuracy of this method was 100%.This method was used to screen 779 kinds of compounds in 30 tea beverage samples.The results showed that didecyl dimethyl ammonium chloride was found in two samples.This method is high efficiency,sensitive and accuracy,which can meet the requirement for non-target rapid screening of pesticide residues in tea beverage.