Insight into BPA–4-vinylpyridine interactions in molecularly imprinted polymers using complementary spectroscopy techniques

Abstract

The influence of solvent polarity on the nature and extent of non-covalent interactions responsible for BPA:4-Vinlypyridine complex formation has been investigated in the pre-polymerization mixture and correlated with polymer-ligand recognition. The combination of FTIR, 1H NMR and UV–Vis spectroscopy has made possible the development of a more comprehensive understanding of pre-polymerization events at a molecular level, and how they govern the properties of subsequent polymerized MIPs. The MIP ATR characterization provides direct insight into the bonding within matrix-template system, confirming that monomer:template H-bonded complexes survived the polymerization process and the presence of two functional monomers in the binding sites. The polymer has shown an excellent affinity for BPA in aqueous solutions with poor recognition in organic solvents. Loss of affinity in organic solvents together with selectivity studies suggested that the binding mechanism depended critically on the conformation of the polymeric binding pockets, which when combined with H-bonding and weak electrostatic interactions allowed for selective recognition.