Issue 20, 2005

Microwave activation of the electro-oxidation of glucose in alkaline media

Abstract

The oxidation of glucose is a complex process usually requiring catalytically active electrode surfaces or enzyme-modified electrodes. In this study the effect of high intensity microwave radiation on the oxidation of glucose in alkaline solution at Au, Cu, and Ni electrodes is reported. Calibration experiments with the Fe(CN)63−/4− redox system in aqueous 0.1 M NaOH indicate that strong thermal effects occur at both 50 and 500 μm diameter electrodes with temperatures reaching 380 K. Extreme mass transport effects with mass transport coefficients of kmt > 0.01 m s−1 (or kmt > 1.0 cm s−1) are observed at 50 μm diameter electrodes in the presence of microwaves. The electrocatalytic oxidation of glucose at 500 μm diameter Au, Cu, or Ni electrodes immersed in 0.1 M NaOH and in the presence of microwave radiation is shown to be dominated by kinetic control. The magnitude of glucose oxidation currents at Cu electrodes is shown to depend on the thickness of a pre-formed oxide layer. At 50 μm diameter Au, Cu, or Ni electrodes microwave enhanced current densities are generally higher, but only at Au electrodes is a significantly increased rate for the electrocatalytic oxidation of glucose to gluconolactone observed. This rate enhancement appears to be independent of temperature but microwave intensity dependent, and therefore non-thermal in nature. Voltammetric currents observed at Ni electrodes in the presence of microwaves show the best correlation with glucose concentration and are therefore analytically most useful.

Graphical abstract: Microwave activation of the electro-oxidation of glucose in alkaline media

Article information

Article type
Paper
Submitted
11 Jul 2005
Accepted
17 Aug 2005
First published
30 Aug 2005

Phys. Chem. Chem. Phys., 2005,7, 3552-3559

Microwave activation of the electro-oxidation of glucose in alkaline media

M. A. Ghanem, R. G. Compton, B. A. Coles, A. Canals, A. Vuorema, P. John and F. Marken, Phys. Chem. Chem. Phys., 2005, 7, 3552 DOI: 10.1039/B509784C

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