Selective determination of nicotinamide adenine dinucleotide in the presence of ascorbic acid and uric acid at a long-length carbon nanotube electrode

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 200μm (average), whereas normal-length CNT as a comparison is 1μm (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 0.030-2.0mM in the presence of 1.2mM AA, and 0.059-2.0mM in the presence of 0.12mM UA.