Simultaneous determination of four pesticides residues in rice by modified QuEChERS coupled with GC-MS/MS

Abstract

A QuEChERS pretreatment technique integrated with GC-MS/MS method was founded to determine pesticides residues in rice (Triazophos, Dichlorvos, Chlorpyrifos and Malathion). By comparing and analyzing the eventual recoveries of these analytes, the type of extraction solvents, the amount of salting out agents, water content, and the selection of adsorbents in the QuEChERS method were ameliorated. Finally, the recovery experiment was conducted using acetonitrile as the extraction solvent, 10 mg PSA, 150 mg anhydrous MgSO4, and 50 mg C18 as purification conditions of QuEChERS method. Under the ameliorative conditions, there was a good linear relationship between the peak areas of these pesticides in rice (r2>0.99). At three spiking levels (20, 40 and 200 μg/kg), the recoveries of four pesticides were 75.6–104.0 % with RSD of 1.5–10.2 %, the LOD of 3.4–5.4 μg/kg and the LOQ of 20 μg/kg. This method is easy to operate, highly sensitive, and accurate, greatly improving work efficiency, and providing reference for future exploration in the field of pesticide residues.