Preparation and Recognition Mechanism of Gallic Acid Imprinted Polymers

A series of gallic acid (= 3,4,5-trihydroxybenzoic acid; GA) imprinted polymers were prepared in MeOH by noncovalent imprint technology. Their recognition properties and selectivity were characterized by equilibrium binding experiments. The recognition mechanism of the optimum imprinted polymer MIP3 which was prepared with the molar ratio 4-VP (= 4-vinylpyridine =4-ethenylpyridine)/GA 4:1, was explored by UV spectroscopy, Scatchard-binding-model analysis, as well as structure-relevant binding. The obtained data consistently indicated that the recognition by MIP3 was mainly based on the ionic interaction between the COOH group of GA and the pyridine moiety fixed on the matrix of the polymer. MIP3 showed the maximum specific affinity to GA in H2O/MeOH 1:1 (v/v) at an apparent pH of 4.7 (imprinting factor 18.6). Due to the high imprinting efficacy, the optimum polymer MIP3 can effectively recognize GA in a complex mixture and possesses certainly an important application potential.