Preparation And Evaluation Of The Molecularly Imprinted Polymers For Levofloxacin In Molecular Crowding Condition

Objective Molecular crowding is the new concept to prepare molecularly imprinted polymers which obtained better retention and selectivity,adding the concept into the experiment to get the effect of macromolecular crowding environment in order to prepare new and better MIP.Method In the experiment,a new system of molecular crowding surrounding was firstly developed,composed of polystyrene and tetrahydrofuran,in the presence of template,(S)-ofloxacin.Partial filling capillary electrochromatography(CEC)was utilized to evaluate imprinting effect of the resulting microparticles by chiral separations of ofloxacin.Some important parameters in the preparation,i.e.,template to monomer ratio,influence of cross-linking monomers and functional monomer composition on the CEC separation of MIP microparticles were investigated.Molecular crowding was also used to prepare monolithic column to evaluate the diversity of MIPs on functional and morphological,in the second part of this work(S)-ofloxacin as the template,MAA and EDMA were functional monomer and cross-linking monomer respectively.Tetrahydrofuran,toluene and DMSO were used as the porogen.Result Baseline separation of ofloxacin(Rs = 1.53)was obtained under optimized conditions(the ratio of template and functional monomer is 1:4)and the highest theory plate of the later eluent(S)-ofloxacin was 5400.The textural and morphological parameters for imprinted particles,it was found that MIP particles prepared by PS-THF system has a unique adsorption-desorption process,such as BET surface areas,pore volumes and pore size distributions have also been determined.The anisotropy of pores showed the maximum b value of 2.86.The cavities in monolithic column showed large BET areas with the maximum is 371.9 m~2/g and the pore volume is 0.28 cm~3/g.Pore diaMeters were concentrated in the range of 5 nm while the minimum is 3.6 nm.The anisotropy of pores(0.71<b<0.81)showed the pores in monolithic column were all oblate and polar solvent decreased retention of MIPs.Conclusion In our study,Using polystyrene as molecular crowding agents,PS-THF as the existence of a molecular crowding porogen system,we successfully developed the techniques of MIP particles prepared by precipitation polymerization.Compared to the MIP microparticle prepared by conventional precipitation polymerization,the(S)-ofloxacin-imprinted particles formed under molecular crowding conditions showed higher selectivity and separation efficiency in CEC mode.In the study of monolithic column,it was found that the anisotropy of pores were similar although the MIPs prepared by different ratio of template and functional monomer.The pores were all oblate and polar solvent decreased retention of MIPs.It was proved the effect of dimerization is distinct in polar solvent.