β‐Methylumbelliferone Surface Modification and Permeability Investigations at PENTEL^™ Graphite Electrodes

Abstract

Electrochemical and micro‐imaging analysis of a commercial graphite‐composite material is presented following electro‐oxidation with β‐methylumbelliferone. Charge‐transfer surface modification was observed for the graphite electrode, presumed to have arisen from adsorbed interfacial umbelliferone moieties. The molecular permeability of the new surface towards a range of similar, yet size‐variable (23 Å3–136 Å3) molecular redox probes is discussed. Red‐shift fluorescence in confocal microscopy offers further support for the presence of a surface‐bound umbelliferone layer. An SEM‐platinum profiling technique was used as an imaging tool to map the umbelliferone surface and size‐distribution of electro‐active sites.