Study of the nature of recognition in molecularly imprinted polymer selective for 2-aminopyridine Original Research Article

A molecularly imprinted polymer was prepared using 2-aminopyridine as the template molecule and methacrylic acid as the functional monomer. The bulk polymer obtained was ground up, sieved and investigated in equilibrium binding experiments to evaluate the binding characteristics of the 2-aminopyridine-imprinted polymer and increase understanding of the mechanisms of recognition in molecularly imprinted polymers. Scatchard analysis showed that a equal class of binding sites were formed in the imprinted polymer under this studied concentration range, and the dissociation constant and the maximum number of these binding sites were estimated to be 2.56 mM and 135.7 μmol g−1 dry polymer, respectively. The polymer gave much higher binding capacity for 2-aminopyridine than the non-imprinted polymer with the same chemical composition. The selectivity was evaluated by distribution coefficients of 2-aminopyridine and other structurally similar compounds. The results showed that the imprinted polymer exhibited high affinity for 2-aminopyridine among the tested compounds. 1H NMR and UV-visible spectrophotometric studies indicated that the selective binding interaction between the template and binding sites in the polymer arose from their cooperative hydrogen-bonding.