A simple swell‐penetration method for the controlled preparation of magnetic polymer microspheres (MPMs) was developed. The polymer microspheres (PMs) were prepared using glycidyl methacrylate as monomer and trimethylolpropane trimethacrylate as crosslinker. The PMs was functionalized by coupling sulfonate groups, and then formation of the MPMs in the presence of ferrous sulfate by swell‐penetration method. The morphology, size, and magnetic properties of the MPMs were characterized by SEM, using a vibrating sample magnetometer, and by FTIR. The results showed that the average particle size was about 1.1 μm, the surface of the microspheres was smooth, and saturated magnetization was 13.8 emu g−1. The adsorption isotherms and kinetics between bovine serum albumin and the MPMs under the optimized adsorption conditions were investigated. The MPMs were further applied to the selective separation of serum albumin from human whole blood. Simultaneously, the adsorption and separation of melamine from milk using the MPMs was investigated. The MPMs showed promising potential for separation of protein and cationic small molecular compound. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 48019.

A restricted‐access material–hybrid monolithic column was prepared based on single‐component organosiloxane and dynamic grafting of δ‐gluconolactone for on‐line solid phase extraction of tetracycline antibiotic residues from milk. The hybrid monolithic column was prepared in a stainless‐steel chromatographic column using methyltrimethoxysilane as the single precursor. δ‐Gluconolactone was covalently coupled to aminopropyl derivatized hybrid monolithic column, which formed hydrophilic structures on the surface of the pore of the restricted‐access material–hybrid monolithic column. The columns were characterized by scanning electron microscopy, thermogravimetric analysis, Fourier transform infrared spectroscopy, nitrogen adsorption, contact angle analysis, dynamic adsorption, and chromatographic performance evaluation. The restricted‐access material–hybrid monolithic column was applied to the on‐line extraction of tetracycline residues from milk. An enrichment factor of 15.8 and a good sample clean‐up effect were obtained under the optimized conditions. The recoveries of the three spiked milk samples were between 81.7 and 102.5% with relative standard deviations (n = 3) in the range of 2–5%. The limits of detection (S/N = 3) for target compounds were in the range of 3.80–9.03 μg/kg. The results show that the on‐line extraction using the restricted‐access material–hybrid monolithic column was powerful for food sample pretreatment with high selectivity and good clean‐up effect.

Activators regenerated by electron transfer-atom transfer radical polymerization (ARGET-ATRP) was applied to the continuous grafting of polybasic polymers and poly(ethylene glycol) (PEG) brushes on the surface of the magnetic microspheres (MMs). At first, the MMs were coated with silica gel, modified by amino group, and then 2-bromoisobutyryl bromide was grafted on the surface of MMs. After that, the hydrophilic polymer brushes magnetic microspheres (HMMs) were prepared by polymerization on the surface of the MMs. HMMs were characterized by transmission electron microscope (TEM) and Fourier transform-infrared (FT-IR) spectrometer. The adsorption performance to protein was studied. The results demonstrated that HMMs have the relatively uniform particle size, good dispersity and excellent protein resistance properties. Tetracycline antibiotics (TCs, tetracycline hydrochloride, chlortetracycline hydrochloride and doxycycline hydrochloride) in honey samples were determined by magnetic dispersion solid phase extraction (MDSPE) using the prepared HMMs and high performance liquid chromatography (HPLC). The average recoveries were obtained in the range of 85.8%-94.5%. The limits of detection (LODs) and limits of quantification (LOQs) of the proposed method were in the ranges of 1.92-2.56 μg/kg and 6.40-8.53 μg/kg, respectively. The proposed method was successfully applied to fast clean-up and enrichment of the TCs residues in honey.