Synthesis and characterization of 3,4-dihydroxyphenylacetic acid imprinted polymers

Abstract

Eight molecularly imprinted polymers (MIP1–MIP8) were synthesized with different functional monomers and porogens using 3,4-dihydroxyphenylacetic acid (DOPAC) as a template. Thermal, radical bulk polymerization was employed in the presence of ethylene glycol dimethacrylate as a cross-linker. A computational analysis indicated that complexes with four molecules of 4-vinylpyridine, 1-vinylimidazole and acrylonitrile had high positive enthalpies of formation. The polymers synthesized with these monomers showed an imprinting factor below 1. Polymer MIP8 synthesized with allylamine as the functional monomer, with the highest energy of interaction with DOPAC, was characterized by the highest imprinting factor equal to 1.91. Examination of the binding ability of DOPAC and a group of structurally related compounds showed that the strong interactions between amine groups in the polymer and carboxylic groups in the analyte governed the recognition mechanism. The Langmuir adsorption model and the pseudo-second-order mechanism properly evaluated the MIP8 and non-imprinted polymer 8 adsorption characteristics. Scatchard analysis revealed that MIP8 had two classes of heterogeneous binding sites with Kd(1) = 0.12 µmol L−1 and Kd(2) = 1.46 µmol L−1. Finally, the potential application of MIP8 for separation of DOPAC was demonstrated. Copyright © 2011 Society of Chemical Industry