Fast Screening Ninety-Six Pesticides In Six Kinds Of Agricultural Products By High Performance Liquid Chromatography-Quadrupole/Electrostatic Field Orbit Trap High-Resolution Mass Spectrometry

A high-throughput method for the determination of 96 pesticides in six kinds of agricultural products by liquid chromatography-quadrupole/electrostatic field orbit trap high-resolution mass spectrometry was developed. After extraction with 0. 1% acetic acid in acetonitrile solution and concentration, dispersive solid-phase extraction was further utilized to reduce the matrix interference. The chromatographic analysis was performed on a C-18 column with methanol and 5 mmol/L ammonium acetate solution as the mobile phases with a gradient elution program. The 96 pesticide residues were analyzed in switching positive and negative modes at the same time. With the optimized mass resolution, accurate mass-to-charge ratio extraction of the target pesticide compounds in full scan mode could eliminate matrix interference effectively. Two-stage threshold-triggered full mass scan mode was utilized to further improve the accuracy of qualitative analysis. The linear ranges of all the 96 pesticides were from 1 mu g/L to 200 mu g/L with correlation coefficients greater than 0. 99. By detecting spiked samples, the detection limits were 5 mu g/kg for all the residues and the recoveries were in the range of 58% -105% with the relative standard deviations (RSDs) between 8. 8% and 18. 3%.