Simultaneous Determination of Tolfenpyrad,Flonicamid,Chlorantraniliprole and Flubendiamide in Vegetables and Fruits by High Performance Liquid Chromatography-Tandem Mass Spectrometry

A high performance liquid chromatography-tandem mass spectrometric method was developed for the determination of tolfenpyrad,flonicamid,chlorantraniliprole and flubendiamide in vegetables and fruits.The samples were extracted with acetonitrile and purified by QuEChERS method after salting-out.The solution after purification was evaporated to dryness in a water bath at 40 ℃ under nitrogen and redissolved with 1 mL acetonitrile-water(20 ∶80,by volume).The compounds were analyzed by LC-MS/MS on an XBridgeTM C18 column using acetonitrile-0.1% formic acid as mobile phase by gradient elution.The mass spectrometer was operated under multiple reaction monitoring(MRM) mode with the positive ionization mode.Good linearities were obtained in the concentrations of 0.075-2.0 mg·L-1 for tolfenpyrad and flonicamid and 0.015-0.40 mg·L-1 for chlorantraniliprole and flubendiamide,with correlation coefficients not less than 0.998.The detection limits of flonicamid,chlorantraniliprole,flubendiamide and tolfenpyrad were 0.005,0.002,0.000 5,0.000 8 mg·kg-1,respectively.The recoveries for the four pesticides in vegetables and fruits were between 80% and 95% at fortified levels of 0.05-5.0 mg·kg-1 for tolfenpyrad and flonicamid,and 0.01-1.0 mg·kg-1 for chlorantraniliprole and flubendiamide.The intra-assay and inter-assay RSDs of four compounds were in the ranges of 2.0%-6.1% and 3.3%-7.6%,respectively.The results indicated that the method was suitable for the determination of tolfenpyrad,flonicamid,chlorantraniliprole and flubendiamide in vegetables and fruits sample.