Affinity screening by packed capillary high performance liquid chromatography using molecular imprinted sorbents. II. Covalent imprinted polymers

This study concentrates on the production of covalent molecular imprint polymers (MIPs) as highly selective sorbents for nortriptyline (NOR), a representative tricyclic antidepressant (TCA). The functionalized template contains a polymerizable 4-vinylphenyl carbamate moiety used to bind the template molecule to the polymer matrix. Polymerization with a cross-linker followed by hydrolytic cleavage of the labile carbamate functionality leaves an MIP with selective binding sites capable of binding template through hydrogen bonding interactions. Demonstrated chromatographically through a "selection index", these MIPs showed high selectivity for the template molecule (NOR) among a library of structurally similar compounds. The recognition was found to correlate with structural similarity to the template compound. A direct comparison between covalent and non-covalent molecular imprinting strategies reveals a great deal of improvement in the peak shape of the retained compound resulting from covalent imprinting (evidenced by peak asymmetry factors A.).