NADH Oxidation at the Honey-Comb Like Structure of Active Carbon: Coupled to Formaldehyde and Sorbitol Dehydrogenases

Abstract

We have demonstrated a simple electrode configuration for the oxidation of NADH on active carbon cloth poised at 100 mV (vs. SCE). This design is unique in that it does not require a soluble mediator for NADH oxidation. The response time is on the order of several seconds; the sensor response is linear, selective, and sensitive. The configuration allows for the implementation of virtually any of the dehydrogenase enzymes dependent on NAD+ cofactor. Here we demonstrate the implementation of two such enzymes: formaldehyde dehydrogenase and sorbitol dehydrogenase for the detection of formaldehyde and sorbitol, respectively. The linear range of the formaldehyde and sorbitol sensors is up to 250 μM and the detection limit 2 μM.