Preparation of Erythromycin-Imprinted Polymeric Microspheres by Emulsion Polymerization and Their Adsorption Properties

Abstract

Uniform molecularly imprinted polymeric microspheres(EM-MIPMs) were prepared by emulsion polymerization using erythromycin as the template molecule, methacrylic acid(MAA) as the functional monomer, and ethylene glycol dimethacrylate(EDMA) and sodium dodecylbenzene sulfonate(SBS) as the cross-linker and emulsifier, respectively. The obtained erythromycin-MAA complexes were characterized using ultraviolet(UV) absorption spectroscopy, Fourier-transform infrared(FTIR) spectroscopy, and1H nuclear magnetic resonance(NMR) spectroscopy. The results showed that erythromycin-MAA complexes were obtained by cooperative hydrogen-bonding interactions. The surface features and thermal stability of the EM-MIPMs were investigated using scanning electron microscopy(SEM) and thermal gravimetric analysis(TGA). The average diameter of the EM-MIPMs was 4.24 μm, larger than non-imprinted polymeric microspheres. They exhibited excellent thermal stability. Kinetic, equilibrium adsorption, and selectivity adsorption experiments(solid-phase extraction) were used to evaluate the binding properties and molecule recognition characteristics of EM-MIPMs for erythromycin. The experimental kinetic data were well described by a pseudo-second-order kinetic model. Erythromycin binding was examined using the Langmuir and Freundlich isotherm models. The EM-MIPMs had an excellent affinity for erythromycin. The equilibrium experimental data for the EM-MIPMs fitted the Langmuir isotherm well, and the binding amount reached 0.242 mmol g-1. Furthermore, solid-phase extraction experiments demonstrated that the EM-MIPMs had a higher affinity for the target molecules than for roxithromycin and erythromycin ethylsuccinate.