Preparation And Evaluation Of The Molecularly Imprinted Polymers For Levofloxacin

Molecular imprinting is a new technique for synthesizing material of molecular recongnition with the ability of pre-selectivity. Molecularly imprinted polymers (MIPs) are prepared by copolymerizing functional and cross-linking monomers in the presence of a template. After the removal of the template, the synthesized MIPs possess micro-cavities with a three-dimensional structure complementary in both shape and chemical functionality to that of the templates, and are able to rebind the templates. Up to date, they have been successfully used in many fields.Molecular crowding, a new cencept of molecular imprinting, was applied to improve selectivity and capicity of MIPs. In this work, with methacrylic acid (MAA) as functional monomer, ethylene glycol dimethacrylate (EDMA) as cross linker, polystyrene as molecular crowding agent, an imprinted monolith was synthesized by an in-situ polymerization with levofloxacin (S-OFX) as template. The results of chromatographic analysis indicated that the adding of PS increased the binding sites and the selectivity of resulting MIPs about 12 times than that without PS.Due to the complication of template with different structure, it is a hard work to obtain MIPs of high selectivity with conventional monomer. Combination of different monomers is an approach to increase of selectivity of MIPs. With MAA and protoporphyrin as functional monomer, EDMA as cross linker, in this work, a number of imprinted and non-imprinted polymers were synthesized by precipitation polymerization in the presence of a model imprinting molecule, S-OFX. An imprinted polymer prepared in the combination of protoporphyrin and MAA (1:1) exhibited much more recongnition sites for template than that of an imprinted polymer prepared only with MAA or protoporphyrin, with an of adsorption capacity (Qmax) of 238.64μmol/g. The results here indicated that the cooperative use of the protoporphyrin with supplemental different functional monomers may be an alternative to obtain MIP with the improvement of the selectivity.