Abstract: In this study, 3-[2-(2-aminoethylamino) ethylamino] propyltrimethoxy functional iron oxide (Fe3O4@SiO2-PAAA) magnetic nanoparticles (MNPs) were prepared by a chemical co-precipitation method and silanization reaction and used to simplify the QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) method and simultaneously improve the purification efficiency. MNPs were characterized by transmission electron microscopy, Fourier transform infrared spectroscopy, vibrating sample magnetometry, X-ray photoelectron spectroscopy, and zeta potential analysis. A modified QuEChERS method was developed using Fe3O4@SiO2-PAAA as an adsorbent for detecting seven pesticide residues in fruits and vegetables using gas chromatography-tandem mass spectrometry (GC-MS/MS). Under the optimized conditions, the developed method showed a good linear relationship in the concentration range between 0.007 and 1.000?mg/kg with correlation coefficients (r2) above 0.994. The limits of quantitation (LOQs) for the method were between 0.007 and 0.017?mg/kg. At LOQ, 2?LOQ, and 10?LOQ fortification levels, the recoveries were in the range from 75.2% to 105.4% for the seven pesticides, with relative standard deviations (RSDs) between 3.7% and 15.7%. This method is fast, accurate, effective and sensitive, and can be used as a reference method for the analysis of pesticide residues in fruits and vegetables.

Key words: QuEChERS; pesticide residues; magnetic nanoparticles; clean-up