NADH oxidation at the honey-comb like structure of active carbon: Coupled to formaldehyde and sorbitol dehydrogenases

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 uniq ue in that it does not require a soluble mediator fur NADH oxidation. The r esponse time is on the order of several seconds; the sensor response is lin ear, selective, and sensitive. The configuration allows for the implementat ion of virtually any of the dehydrogenase enzymes dependent on NAD(+) cofac tor. Here we demonstrate the implementation of two such enzymes: formaldehy de dehydrogenase and sorbitol dehydrogenase for the detection of formaldehy de and sorbitol, respectively. The linear range of the formaldehyde and sor bitol sensors is up to 250 muM and the detection limit 2 muM.