Rapid and Sensitive Detection of Avermectin Residues in Edible Oils by Magnetic Solid-Phase Extraction Combined with Ultra-High-Pressure Liquid Chromatography-Tandem Mass Spectrometry

A rapid, simple, and sensitive method was developed for the detection of avermectin residues in edible oils based on magnetic solid-phase extraction (MSPE) followed by ultra-high-pressure liquid chromatography-tandem mass spectrometry (UPLC-MS/MS)-based method. Bare Fe3O4 microspheres that were simply prepared by the hydrothermal method were directly used as sorbents of MSPE to enrich target avermectin residues from complex edible oil samples based on hydrogen bond and other polar interactions. To the best of our knowledge, this is the first report of bare Fe3O4 directly used as efficient extraction sorbent to enrich avermectin residues. The effects of experimental variables, such as the amount of sorbents, loading, washing, and eluting solvents, have been studied in detail. Under the optimized conditions, the method validation was performed in terms of linearity, recovery, and precision. Good linearities for three avermectin residues were obtained with R-2 ranging from 0.9992 to 0.9997. The limits of detection (LODs) and quantification (LOQs) ranged from 0.02 to 0.85 mu g/kg and 0.07 to 2.83 mu g/kg, respectively. The method recoveries of three avermectin residues spiked at three concentration levels in a blank sample were from 83.8 to 101.3%, with inter- and intra-day relative standard deviations (RSDs) less than 8.9%.