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Published July 28, 1995 | public
Journal Article

Molecularly imprinted polymers on silica: selective supports for high-performance ligand-exchange chromatography

Abstract

Thin coatings of molecularly imprinted, metal-complexing polymers have been grafted to activated silica beads suitable for high-performance liquid chromatography (HPLC). Propylmethacrylate-activated silica particles were coated by copolymerization with a metal-chelating monomer, Cu^(2+)-[N-(4-vinylbenzyl)-imino]diabetic acid, a metal-coordinating (imidazole) template, and ethylene glycol dimethacrylate. After extraction to remove the template and re-loading with metal, the composite materials re-bind the templates with which they were prepared and exhibit selectivities comparable to bulk-polymerized imprinted materials. The strong Cu^(2+)-imidazole interaction, desirable for creating a high-fidelity imprint, leads to excessive retention in elution chromatography. By replacing the copper in the imprinted metal-complexing polymers with weaker-binding Zn^(2+), these novel ligand-exchange supports can effect partial to complete chromatographic separation of their bis-imidazole templates from other, highly similar imidazole-containing substrates. This "bait-and-switch" approach can significantly enhance the performance of molecularly imprinted materials. Scatchard plots of equilibrium binding data show a significant degree of heterogeneity in the imprinted binding sites of material prepared with a bis-imidazole template, but not with a mono-imidazole template. The best chromatographic separations are observed with small sample sizes, where the substrates occupy the strongest (highest-fidelity) sites.

Additional Information

© 1995 Published by Elsevier B.V. First received 23 December 1994; revised manuscript received 17 March 1995; accepted 17 March 1995. This research is supported by the National Science Foundation (BCS-9108502) and the Office of Naval Research (N00014-92-J-1178). F.H.A. acknowledges an NSF Presidential Young Investigator Award and a fellowship from the David and Lucile Packard Foundation. S.P. acknowledges a predoctoral training fellowship in biotechnology from the National Institute of General Medical Sciences, NRSA Award 1 T32 GM 08346-01.

Additional details

Created:
August 20, 2023
Modified:
October 18, 2023