Electrochemistry of nicotinamide adenine dinucleotide (reduced) at heated platinum electrodes

This paper reports on the electrochemical behavior and determination of nicotinamide adenine dinucleotide reduced (NADH) at indirectly electrically heated platinum electrodes. At room temperature, a surface fouling can be observed during voltammetric and amperometric measurements, whereas a slight electrode heating during the measurements greatly minimizes such electrode passivation. This is illustrated by repetitive cyclic and square-wave voltammetric scans as well as using amperometry. The effect of electrode temperature and NADH concentration is evaluated. Amperometric calibration data exhibit a 10-fold higher sensitivity upon elevating the electrode temperature from 22 to 75 °C. Furthermore, the amperometric response at the hot Pt-electrode is very stable, with 86% of the initial activity remaining after 20 min stirring of 5 mM NADH (compared to 32% under cold conditions). This represents the first example of using heated electrodes for minimizing surface fouling effects. The ability of heated Pt-electrodes to promote the NADH electron-transfer reaction suggests great promise for dehydrogenase-based amperometric biosensors.