Molecular imprinting of antibiotic films for electroanalysis of the dopamine/ascorbate system

Abstract

Molecular films of a natural antibiotic lasalocid A have been cast on the surface of glassy carbon electrodes and used fm the differentiation of electrochemical signals in the model system composed of dopamine and ascorbate. The best signal resolution is obtained at the films that were prepared by evaporating solvent from a chloroform solution of lasalocid that was equilibrated with an aqueous solution of dopamine. The improved selectivity of such films is ascribed to their enhanced hydrophobicity. The latter is hypothesized to be the result of lasalocid 's compact cyclic conformation, which was imprinted

in the solid films by the complexation with dopamine. When operated at a constant potential of 0.20 V, the lasalocid-based dopamine sensors are free of interferences from ascorbate and displayed low detection limits (~70 n<i>M</i> dopamine, S/N=3) in conjunction with fast response times (~0.4s).