Preparation Of Alkaloid Surface Molecular Imprinting Polymer Sed On Benzene Sulfonate Groups Silica Gel Particles And Research On Its Specific Binding Property

Alkaloid is the main active ingredient contained in Chinese herbal medicine and various of alkaloids have different pharmacological activities. But it is very complicated to purify the alkaloid from the crude extract and the traditional liquid-liquid extraction is high cost and low efficiency. In this paper, the synthesis of novel adsorption materials for matrine and cytisine is investigated and the adsorption character and mechanism is researched. The experimental results have important reference values for separating alkaloid.Micro-sized silica gel particles were first surface-modified with γ--mercaptopropyltrimethoxysilane (MPMS) as coupling agent, obtaining the modified particles MPMS-SiO2. Subsequently, a surface-initiating system was constituted between the thiol groups on the surfaces of MPMS-SiO2particles and2,2’-azobis(2-methylpropionitrile)(AIBN) in the organic solvent, namely the thiol-AIBN initiating system was formed. The "surface-initiated graft-polymerization" of glycidyl methacrylate (GMA) was carried out and the grafted particles PGMA-SiO2with a high grafting degree of23g/100g was prepared. The effects of the main factors on the graft-polymerization of GMA were examined, and the mechanism of the surface-initiated graft-polymerization was explored.Then the ring-opening reaction of the epoxy groups of the grafting macromolecule PGMA was carried out by sodium4-aminobenzenesulfonate (SAS), leading to sodium benzenesulfonate groups were bonding onto the side chains of the grafting macromolecule PGMA and resulting in the functional grafting particles SAS-PGMA/SiO2. The effects of the main factors on the ring-opening reaction were examined. On this basis, the adsorption capacity and adsorption mechanism of SAS-PGMA/SiO2for matrine and cytisine in water are furtherly studied. The experimental results show that the functional particles SAS-PGMA/SiO2has strong adsorption ability towards alkaloid such as matrine and cytosine. The driving force of the adsorption is the synergism of electrostatic and hydrogen bond interaction. The adsorption capacity has a maximum value at pH=6. The reaction temperature can exert great effect on the adsorption property and the adsoiption capacity is decreased with the increase of the temperature.By the same method, the functional particles DSAS-PGMA/SiO2were prepared with2,4-diamino-benzenesulfonic aci sodium salt(DSAS) as the reagent. On this basis, the matrine molecule surface-imprinting was performed through Schiffs base reaction with glutaraldehyde as crosslinking agent and matrine as the template, and the matrine molecule surface-imprinted material MIP-SASP/SiO2was prepared. Both static and dynamic methods were adopted to study the binding properties and molecule recognition character of MIP-DSASP/SiO2for matrine. The experiment results show that MIP-DSASP/SiO2possesses strong recognition capability for matrine. In relation to oxymatrine and cytisine, the selectivity coefficient of SAS-PGMA/SiO2for matrine is0.9and1.9, and that of MIP-DSASP/SiO2for matrine is5.6and10.7. Besides, MIP-DSASP/SiO2has excellent elution property.Finally, MIP-DSASP/SiO2was prepared with cytisine as a template molecule and glutaraldehyde as crosslinking agent by right of the intermolecular hydrogen bond and electrostatic interactions between the grafted DSAS-PGMA/SiO2macromolecules and cytisine molecules. Both static and dynamic methods were adopted to study the binding properties and molecule recognition character of MIP-DSASP/SiO2for cytisine. The experiment results show that MIP-DSASP/SiO2possesses strong recognition capability for cytisine. In relation to matrine and oxymatrine, the selectivity coefficient of SAS-PGMA/SiO2for cytisine is0.86and0.88, and that of MIP-DSASP/SiO2for cytisine is6.5and9.5. Besides, MIP-DSASP/SiO2has excellent elution property.