Self-driven coulometry of ethanol, D-glucose and D-fructose using ubiquinone-dependent dehydrogenase reactions

Self-driven coulometry has been applied to the determination of the substrates of ubiquinone-dependent dehydrogenase, and the optimum conditions for the absolute determinations of the reduced ubiquinone, ethanol, D-glucose and D-fructose were obtained. The reduced ubiquinone was oxidized directly at the working carbon felt electrode of the coulometric cell with the counter carbon felt electrode impregnated with hexacyanoferrate(III) ion counter solution, driven by the electromotive force generated between both electrodes. Ethanol, D-glucose and D-fructose are oxidized by ubiquinone, catalyzed by dehydrogenases and each dehydrogenase reaction of these substrates proceeded completely prior to the addition of the sample on the carbon felt electrode surface. Consequently, all of these analytes have been determined with nearly 100% discharging efficiencies, and self-driven coulometry coupled with ubiquinone-dependent dehydrogenase reactions has been estimated as a convenient analytical method for the determination of the biochemical substrates.