Preparation Of Molecular Imprinting Polymer On Silica Gel Particles For Quebrachitol And Specific Binding Property

Quebrachitol is an important crude material of naturally chiral drugs and is used as aprecursor to synthesize many drugs. Quebrachitol mainly found in natural ruber whey,accounting for0.2%~1.2%. The purpose of this study is to work out a polar water-solutionMIPs with high selectivity, which as the sepration medium of preparative chromatography toextract quebrachitol from nature products.Firstly, the micro-sized silica gel particles were surface-modified with3-aminopropyltrimethoxysilane(AMPS) as coupling agent, which made amino groups bondedto the surfaces of silica gel particles, obtaining the modified particles AMPS-SiO2. Then4-Vinyl pyridine(4-VP) is grafted on the surface of particles with the method of “graft from”,and the grafted particle P4VP/SiO2is prepared. The grafted particle P4VP/SiO2ischaracterized by infrared(FTIR)、thermogravimetry(TG) and scanning electronic meter(SEM).The experimental results show that the graft polymerization of4-VP onto the surface of silicagel particles can successfully be realized using the method of”graft from”. The optimalpreparation condition for silica gel with high graft degree is: temperature is50℃, theconcentration of monomer is20%and concentration of initiator is1.4%.As the basis of preparation of molecular surface imprinting polymer, the adsorptionmechanism of P4VP/SiO2for quebrachitol in water is further studied. The influence oftemperature and pH on adsorption capacity is stydied. The experimental results show that thegrafted particle P4VP/SiO2has strong adsorption ability for quebrachitol. The driving force ofthe adsorption is the synergism of hydrogen bond and hydrophobic interaction. WhenpH<7,the adsorption capacity increases with the increase of pH value, decreases with theincrease of pH value as pH>7, and when pH=7, the adsorption capacity has a maximum; The adsorption capacity decreases with the enhancement of temperature.To establish a method for the determination of qubrachitol by hydrophilic interactionchromatography-evaporative light scattering detection(ZIC-HILIC-ELSD). The separationwas performed on a HILIC column(150×4.6mm,5μm) with acetonitrile-water(70:30) asmobile phase at a flow rate of1.0mL/min. The evaporate temperatures and atomizationtemperatures of the ELSD were set at65℃and50℃，the air carrier gas pressure was9.9MPa. There was a good linear relationship with the range of0.08~8mg/mL. The averagerecovery was100.3%(RSD=0.58%). The method can be used for the quantitativedetermination and quality control of quebrachitol.The molecular imprinting towards the grafted P4VP was conducted with quebrachitol astemplate molecule and1,6-dibromohexane as crosslinking agent by using the novelsurface-molecular imprinting technique. The selective binding properties of MIP-P4VP/SiO2for quebrachitol and repeated using capacity are studied. The experiment results show thatMIP-P4VP/SiO2possess strong recognition capability for quebrachitol. In relation to shikimicacid, the selectivity coefficient of P4VP/SiO2for quebrachitol is1.28, and that ofMIP-P4VP/SiO2for qubrachitol is4.84, and the adsorption capacity of MIP-P4VP/SiO2isstill stable after using of8times.