Study of the binding characteristics of molecular imprinted polymer selective for cefalexin in aqueous media.

A molecularly imprinted polymer was prepared using cefalexin as the template molecule and 2-(trifluoromethyl)acrylic acid as the functional monomer. The bulk polymer was ground, sieved and investigated in an equilibrium binding experiment to evaluate the binding characteristics of the cefalexin-imprinted polymer for a better understanding of the mechanisms of recognition in molecularly imprinted polymers. Scatchard analysis showed that two classes of binding sites were formed in the imprinted polymer under the concentration studied. The dissociation constants were estimated to be 0.14 mmol/L and 2.38 mmol/L. The polymer gave much higher binding capacity for cefalexin than the non-imprinted polymer with the same chemical composition. The selectivity was evaluated by distribution coefficients of cefalexin and other structurally similar compounds. The results showed that the imprinted polymer exhibited high affinity for cefalexin among the tested compounds.