Rapid and accurate determination of NADH by an amperometric sensor with a bilayer membrane consisting of a polyion complex layer and an NADH oxidase layer

An amperometric NADH-sensing electrode was prepared by immobilizing NADH oxidase on a poly-l-lysine/poly(4-styrenesulfonate)-complex-coated electrode. The polyion complex layer was effective for eliminating electrochemical interferents such as l-ascorbic acid, uric acid and acetaminophen, whereas the hydrogen peroxide produced through the NADH oxidase-catalyzed reaction permeated rapidly through the layer. This resulted in a rapid response with a low interference level. An alcohol dehydrogenase/NADH oxidase–bienzyme electrode was also prepared for the measurement of alcohol, and for the highly sensitive measurement of NADH, which was based on the substrate recycling with the dehydrogenase-catalyzed reaction.