Abstract

Molecularly imprinted polymers (MIP) are tailor-made polymers with high selectivity for the template molecule. This selectivity arises from the synthetic procedure followed to prepare the MIP. In this work, the influence of process parameters on the preparation of oligomeric procyanidins (OPC) imprinted polymers was presented. In the procedure of polymerization, OPC (90 mg) was used as the template molecule, azobisisobutyronitrile (AIBN), was employed to initiate the reaction with 360 nm UV light at 4°C. The influence of the following parameters was investigated: the moles of functional monomer (MAA, 0.2 - 0.8 mmol), the moles of cross-linker (EDMA, 2.0 – 4.0 mmol) and the porogenic solvent (acetonitrile, acetone or ethyl acetate). A mathematical method of response surface methodology (RSM) was applied to optimize these selected parameters in order to increase the selectivity of MIP for template molecule. The MIP was synthesized under the optimal conditions that 0.68 mmol of MAA and 3.3 mmol of EDMA copolymerized in ethyl acetate by regression analysis in the presence of 90 mg of OPC. After removal of the template molecule, the obtained MIP was then employed as the sorbents of solid-phase extraction (SPE) to separate OPC from lotus seedpod extracts. The results showed that the polymer exhibited high affinity to the template molecule and could separate and enrich OPC from lotus seedpod extracts effectively. A selective recovery of OPC on the optimal MIP was obtained 85.58%. Therefore, the nature of the polymer can be improved by optimizing the polymerization parameters with the method of RSM.

Key words: Molecularly imprinted polymer, polymerization, response surface methodology, parameter optimization, oligomeric procyanidins.