Artemisinin Molecular Imprinting Polymers With Calix[4] Arene On Silica Surface And Its Separation Behavior In Supercritical CO₂ Fluid

In this paper, a new method, surface polymerization, was used to prepare the molecular imprinting polymers on silica surfaces, whose separation behavior at atmosphere pressure and room temperature was studied comparing with that in supercritical CO2 fluid. The surfaces of porous silica were first modified by y-Glycidoxypropyltrimethoxysolane (GPTMS) as a coupling reagent, and then molecular imprinting polymers (MIPs) for artemisinin were prepared at room temperature by calix[4]arene bonded on silica particle surface and free 3-aminopropyltriethoxysilane as functional monomers, tetraethoxysilicane as cross-linker, artemisinin as a template, petroleum ether as solvent. The recognization and adsorption capacity evaluating the prepared MIPs were tested by static adsorption method. The best ratio of template, monomers and cross-linker was 1:4:20 via the optimization test and the MIPs showed high adsorption capacity and good selectivity for artemisinin. The maximum adsorption capacity of MIPs for artemisinin was 42 mg/g and the equilibrium of MIPs adsorbing artemisinin was reached within 10h. The imprinting factor and the selective factor of the artemisinin-imprinting polymers were 2.0 and 1.5 respectively.The adsorption capacity was also researched in the supercritical CO2 fluid with pressure at 20MPa and temperature at 40℃.The imprinted film coating onto the silica surface possessed a fast kinetics for recognizing and adsorbing templates. Especially, the mass transfer reached the equilibrium within 3.5h in supercritical fluid system and the adsorption capacity was higher to 120mg/g.