Preparation and characterization of molecularly imprinted silica monolith for screening sulfamethazine

In this work, a novel approach of preparing molecularly imprinted film-derivatized silica monolith materials was developed by a two-step procedure. The silica monolithic support was first prepared by the sol-gel method with tetramethoxysilane as the precursor. Subsequently, vinyl groups were introduced onto the surface of silica monolith by immobilization of γ-methacryloxypropyltrimethoxysilane. The prepolymerization mixtures, consisting of methacrylic acid as a functional monomer, ethylene dimethacrylate as a crosslinker, sulfamethazine as a template molecule and an ionic liquid as porogen, were injected into the silica monolith immobilized vinyl groups to form the molecularly imprinted films on the surface of the vinyl functionalized silica monolith. The monolithic materials were characterized by SEM, Fourier transform IR and solid-state reflection UV spectra. The resulted imprinted materials were evaluated under CEC and HPLC mode. The results indicated that there were enough recognition sites on the surface of the imprinted film-derivatized monolithic materials for selectively recognizing sulfamethazine from the sulfonamide mixture. Ionic liquids, which was utilized as the porogens, could improve the flow-through property and the imprinting effect of the molecularly imprinted film-functionalized silica monolithic materials.