Separation of hydroxybenzoic acid isomers using the molecular imprinting technique

Molecular imprinting polymers (MIPs) for salicylic acid (SA), 3-hydroxybenzoic acid (3HBA), and 4-hydroxybenzoic acid (4HBA) were synthesized using styrene and 4-vinylpyridine (4-VPy) as functional monomer and divinylbenzene (DVB) as crosslinker. The adsorption characteristics of hydroxybenzoic acid (HBA) isomers on each MIP were investigated. The materials used for the polymerization of each 3HBA and 4HBA-MIPs were adsorbed relatively well. This verifies that the MIPs that can adsorb template selectively were synthesized. However, SA-MIP had no molecular imprinting effect. SA has intramolecular hydrogen bond and it is difficult to adsorb on recognition site of SA-MIP, because its structure differs from that of recognition site of SA-MIP. It indicates that SA-MIP had no recognition effect. 1,2,3,4-Tetrahydro-1-naphthol (THN)-MIP was synthesized, which is similar to SA with intramolecular hydrogen bond. SA was separated selectively using THN-MIP. (C) 2007 Wiley Periodicals, Inc.