The Preparation Of Polysaccharide Molecularly Imprinted Polymers And The Behavior Of Hydrophilic Interaction Chromatography

Molecularly imprinted polymers,as an "artificial antibody",have the advantage of specific recognition,but they are mainly used in small molecule research and sample pretreatment.Chromatography technology has a high sensitivity and other characteristics,in which the hydrophilic chromatography on the polar compounds have a better separation effect.Therefore,this paper selected starch as a template molecule,and prepared starch polysaccharide molecularly imprinted polymer successfully.Then it was used in the study of hydrophilic interaction liquid chromatography(HILIC),and the retention behavior and mechanism of different kinds of solutes in this new type of column were explored.The main contents and results are as follows:In the first part,two kinds of bifunctional monomers with 3-aminobenzeneboronic acid(APBA)and 2-propylamide-2-methylpropanesulfonic acid(AMPS)were selected by the equimolar continuous transformation method.The silica(Si O2)particles were synthesized by St?ber method as the carrier,and the surface was modified with epoxy groups.The grafting conditions were optimized.Then,using surface molecular imprinting method to synthesize starch polysaccharides molecular imprinted polymers in an alkaline aqueous environment with epoxy-modified Si O2 as a carrier,starch as template molecule,APBA and AMPS as bi-functional monomer,ammonium persulfate as an initiator.Characterize the imprinted polymer by transmission electron microscopy,scanning electron microscopy,infrared spectroscopy and thermogravimetric analyzer.In the second part,the adsorption rate of starch polysaccharide molecularly imprinted polymer(SMIPs)was higher than that of starch polysaccharide nonmolecularly imprinted polymer(SNIPs)by measuring the adsorption rate,adsorption isotherm curve and adsorption selectivity.The results showed that SMIPs had specific recognition effect on template molecules,and the imprinting factors reached 2.22.Then the adsorption kinetic model of SMIPs was studied by fitting the adsorption amount to the adsorption concentration.The results show that the adsorption process of SMIPs is mainly dominated by chemical adsorption between adsorbents and adsorbed masses through electron sharing or transfer,and pore diffusion plays a supporting role.Analysis of the constructed adsorptionisotherm model,we know SMIPs are homogeneous microspheres,and their adsorption processes are monomolecular adsorption,the whole adsorption process is faster.From the recycling rate last experiment,SMIPs still able to maintain good adsorption effect repeated ten times after adsorption elution,proved that it has good stability and practical performance.In the third part,SMIPs were used as chromatographic fillers to prepare SMIPs hydrophilic columns.Four bases and nucleosides are separated substances and have good peak shapes using acetonitrile-10 mmol/L ammonium formate as the mobile phase gradient elution with 254 nm UV wavelength detection.Four saccharides are completely separated with 80 % acetonitrile-water as the mobile phase under the differential detector.Then the retention behavior of these two substances was investigated by changing the water content,p H,ionic strength of the mobile phase and column temperature in the SMIPs column.The results show that the solute retention factor decreases when the water content in the mobile phase increases,which is consistent with the hydrophilic chromatography.The retention factor of the solute also decreases with the decrease of p H and ionic strength in the mobile phase,while the retention factor of the solute decreases when the column temperature rises,and the specific fluctuation range is related to its polarity and structure.By exploring the retention mechanism of two kinds of substances,it is found that the base and nucleoside substances are affected by the distribution mechanism and the adsorption mechanism.However,the saccharide is dominated by the adsorption mechanism on the SMIPs column because it contains a large amount of ortho-dihydroxy groups on its surface and binds to the ligands on the stationary phase.