Amperometric tetrathiafulvalene-mediated sensor sensitive to reduced nicotinamide adenine dinucleotide based on co-immobilized lactate oxidase and lactate dehydrogenase

Abstract

An amperometric tetrathiafulvalene (TTF) mediated reduced nicotinamide adenine dinucleotide (NADH) sensor has been fabricated by co-immobilizing lactate oxidase and lactate dehydrogenase on an Eastman-AQ-TTF-modified electrode. The sensor provides low detection limits of 0.01 mmol l^–1 NADH and 1.0 µmol l^–1L-lactate and pyruvate by means of amplification of the bioelectrocatalytic oxidation current by the recycling of L-lactate and pyruvate. The response of the sensor to NADH under N₂ saturation reaches a 95% steady-state current within 2 min with a linear response at concentrations of 0.05–2.5 mmol l^–1. The dependence of the apparent Michaelis–Menten constant on applied potential was studied.