Preparation and recognition properties of vanillin-imprinted polymers

Some new molecularly imprinted polymers (MIPs) were prepared by different protocols involving vanillin as the imprinted molecule, methacrylic acid (=2-methylprop-2-enoic acid; MAA) as the functional monomer, and ethylene glycol dimethacrylate (EGDMA=2-methylprop-2-enoic acid ethane-1,2-diyl ester) as the cross-linking agent. The adsorption property of the imprinted polymers was studied by UV spectrophotometry and HPLC. The results indicated that the porogen solvent had a certain influence on the adsorption performance of the polymer. The vanillin-imprinted polymer MIP1 prepared with MeOH as porogen, exhibited advantageous characteristics, i.e., a high binding activity, a good selectivity, and a rapid adsorption equilibrium. The binding parameters studied by Scatchard analysis established that there are two types of binding sites in MIP1. Finally, by packing an SPE column (SPE=solid-phase extraction) with the polymer MIP1, the vanillin was separated and enriched successfully by this sorbent from the samples of Vanilla fragrans and beer.