Rapid magnetic solid-phase extraction based on magnetite/silica/poly(methacrylic acid–co–ethylene glycol dimethacrylate) composite microspheres for the determination of sulfonamide in milk samples

A novel magnetic solid-phase extraction (MSPE) sorbent, magnetite/silica/poly (methacrylic acid–co-ethylene glycol dimethacrylate) (Fe3O4/SiO2/P(MAA-co-EGDMA)), was developed. This MSPE material was prepared by distillation–precipitation polymerization of MAA and EGDMA in the presence of Fe3O4/SiO2 microspheres with the surface containing abundant reactive double bonds. The resultant sorbent material was characterized by elemental analysis, electron microscopy, X-ray diffraction and Fourier-transformed infrared spectroscopy. In this work, eleven sulfonamides (SAs) were selected as model analytes to validate the extraction performance of this new MSPE sorbent. Noticeably, the extraction can be carried out quickly, the extraction time for the SAs onto Fe3O4/SiO2/P(MAA-co-EGDMA) sorbent can be clearly shortened to 0.5 min. The desorption solution of SAs was analyzed by LC–MS/MS, and the results showed that the recoveries of these compounds were in the range of 87.6–115.6%, with relative standard deviations ranging between 0.9% and 10.8%; the limit of detection were in the range of 0.5–49.5 ng/L.