Abstract: 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 C18 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 μg/L to 200 μg/L with correlation coefficients greater than 0.99. By detecting spiked samples, the detection limits were 5 μg/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%.

Key words: agricultural products, electrostatic field orbit trap, high-resolution mass spectrometry, pesticide residues, high performance liquid chromatography (HPLC)