Selective Determination of Nicotinamide Adenine Dinucleotide in the Presence of Ascorbic Acid and Uric Acid at a Long-Length Carbon Nanotube Electrode

Abstract

Selective electrochemical determination of nicotinamide adenine dinucleotide (NADH) in the presence of ascorbic acid (AA) and uric acid (UA) at a long-length multi-walled carbon nanotube (CNT) electrode is presented. We demonstrate the effectiveness of CNT length toward the electrochemical response due to oxidation of NADH. The long-length CNT is 200 µm (average), whereas normal-length CNT as a comparison is 1 µm (average). In differential pulse voltammetry, the current peaks due to NADH, AA, and UA at long-length CNT electrodes were more distinct than those at normal-length electrode. Electrochemical impedance spectroscopy measurements suggested that the long-length CNT electrode formed a better electron transfer network than the normal-length electrode. The performance of selective determination of NADH are concentration range of 0.030–2.0 mM in the presence of 1.2 mM AA, and 0.059–2.0 mM in the presence of 0.12 mM UA.