Synthesizing molecularly imprinted polymer beads for the purification of vitamin E

Molecularly imprinted polymer (MIP) beads imprinted with vitamin E (VE) were synthesized via a two-step swelling polymerization method, using methacrylic acid (MAA) and other functional monomers together with polystyrene (PS) microspheres as the substrate. In initial trials, different functional monomers were assessed, along with a variety of solvents and imprinting ratios. The MIPMAA sample exhibited the highest performance and was characterized and also assessed with regard to VE adsorption under various experimental conditions. This material exhibited reasonably good sphericity, porosity and stability, along with an excellent adsorption capacity of 46 mg/g. This was much higher than the value for the corresponding non-imprinted polymer made with the same monomer, and 20% higher than that for an acrylamide-based MIP synthesized using a precipitation polymerization method. The core-shell structured MIPMAA also demonstrated fast adsorption kinetics, a low pressure drop and good reusability in fixed bed experiments. The VE adsorption equilibrium, selectivity, kinetics, thermodynamics and regeneration capacity of this material were also examined and are reported herein.