We prepared ofloxacin restricted access media molecularly imprinted polymers using surface-initiated atom transfer radical polymerization on the surface of brominated silica gel using ofloxacin as a template molecule, methacrylic acid as a functional monomer, and ethylene glycol dimethacrylate as a crosslinking agent. We then characterized and studied the surface morphology and adsorption properties of the polymer. Experimental results show that saturation is reached within 25 min, and that the saturated adsorption capacity was 80.67 mg/g and the imprinting factor was 1.94. Our findings also showed that the polymer surface had good hydrophilicity and an excellent protein exclusion rate, which was 98.49%. The restricted access media molecularly imprinted polymers were then successfully applied to the enrichment and separation of ofloxacin in bovine serum. When combined with high-performance liquid chromatography, and the average recovery of ofloxacin was 95.6%, and the relative standard deviation was in the range of 2.47-3.38%. In a word, the restricted access media molecularly imprinted polymers is a method that involves a simple preparation procedure that results in excellent performance, which is a great improvement in the speed of detection of antibiotics. These qualities are what bestow upon this method its great potential for broad application.
K E Y W O R D Shigh performance liquid chromatography, molecularly imprinted polymers, ofloxacin, restricted access media, solid phase extraction
Chloramphenicol-(CAP-) restricted access media-molecularly imprinted polymers (CAP-RAM-MIPs) were prepared by precipitation polymerization using CAP as a template molecule, 2-diethylaminoethyl methacrylate (DEAEM) as a functional monomer, ethylene glycol dimethyl acrylate (EDMA) as a crosslinking agent, glycidyl methacrylate (GMA) as an outer hydrophilic functional monomer, and acetonitrile as a pore former and solvent. e CAP-RAM-MIPs were successfully characterized by Fourier-transform infrared spectroscopy, scanning electron microscopy, and thermogravimetric analysis. e adsorption performance was investigated in detail using static, dynamic, and selective adsorption experiments. Adsorption equilibrium could be reached within 11 min. e CAP-RAM-MIPs had a high adsorption rate and good specific adsorption properties. Scatchard fitting curves indicated there were two binding sites for CAP-RAM-MIPs. Adsorption was Freundlich multilayer adsorption and consistent with the quasi-second kinetic model. Using CAP-RAM-MIPs for selective separation and enrichment CAP in bovine serum in combination with highperformance liquid chromatography (HPLC), CAP recovery ranged from 94.1 to 97.9% with relative standard deviations of 0.7-1.5%.is material has broad application prospects in enrichment and separation.
Using magnetic silica (FeO@SiO) as the matrix material, a magnetic reversed-phase restricted access material was prepared via surface-initiation atom transfer radical polymerization (SI-ATRP) on the surface of modified FeO@SiO. Stearyl methacrylate (SMA) was grafted on the inner surface of the modified FeO@SiO, and glycidylmethacrylate (GMA) was grafted on the outer surface of the modified FeO@SiO. The magnetic reversed-phase restricted access material was prepared via acid hydrolysis. This material was characterized by scanning electron microscope (SEM), X-ray diffraction (XRD), transmission electron microscopy (TEM), vibrating sample magnetometer (VSM) and elemental analysis. The exclusion ability of the opened magnetic reversed-phase restricted access material to bovine serum albumin (BSA) was 90.4%. The maximum adsorbed amounts of sulfisoxazole (SIZ), sulfadimethoxine (SDM), trimethoprim (TMP) and sulfamerazine (SMR) were 2.76, 2.24, 1.51 and 1.34 mg/g, respectively. This material was applied to extract and enrich SIZ, SMR and SDM in milk and bovine serum samples. The spiked recoveries of SIZ, SMR and SDM were 88.7%-90.8%, and the relative standard deviations were 3.3%-5.3%. Thus, the magnetic phase restricted access material can simplify the pretreatment of biological matrix samples, and can be applied to the analysis and detection of blood samples or food samples.
The magnetic surface molecularly imprinted polymers (MIPs) with specific recognition of 4-methyl imidazole (4-MI) were prepared by using 4-MI as template molecule, methacrylic acid (MAA) as functional monomer and Fe3O4 as magnetic fluid. The polymers were characterized by of Fourier transform infrared spectrometer (FT-IR) analysis, X-ray diffraction (XRD) analysis, transmission electron microscopy (TEM) and vibrating sample magnetometer (VSM). The results demonstrated that an imprinted polymer layer was successfully coated onto the surface of modified Fe3O4 nanomaterials, resulting in a narrow diameter distribution and good magnetic responsibility. The ultraviolet (UV) spectrophotometry was used to demonstrate the interaction between 4-MI and MAA. It was found that one 4-MI molecule was entrapped by one MAA molecule, which was the main existing form of subject and object. By UV spectrophotometric method to study the adsorption performance of magnetic molecularly imprinted polymers, the specific adsorption equilibrium and selectivity were evaluated by batch rebinding studies. The Scatchard analysis showed that there were two kinds of binding sites in the Fe3O4 @ (4-MI-MIP). The corresponding maximum adsorption capacities of 4-MI onto Fe3O4 @ (4-MI-MIP) were 40.31 mg/g and 23.07 mg/g, and the dissociation constants were 64.85 mg/L and 30.41 mg/L, respectively. The kinetic experimental data were correlated with second-order kinetic model. The magnetic molecularly imprinted polymers were used for the adsorption of 4-methyl imidazole in environmental water samples, and good results were obtained.
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