Electrocatalytic oxidation of NADH based on polyluminol and functionalized multi-walled carbon nanotubes

Abstract

This work presents that the electrocatalytic oxidation of NADH can be enhanced by the hybrid composites of polyluminol and functionalized multi-walled carbon nanotubes (MWCNTs). The hybrid composites can be easily prepared by the electropolymerization of luminol and the adsorption of functionalized MWCNTs. The modified electrode exhibits two redox couples which can show two electrocatalytic peaks at about 0.1 and 0.3 V (vs.Ag/AgCl) to NADH oxidation. The kinetic constant, k_kin, for the electrocatalytic oxidation of NADH, evaluated by chronoamperometry and voltammetry using a rotating disk electrode (RDE), provided values close to 10⁵ M⁻¹ s⁻¹. At an applied potential of 0.1 V, the sensor provides a linear response range for NADH from 5 × 10⁻⁶ up to 1.5 × 10⁻⁴ M with a sensitivity of 183.9 μA mM⁻¹ cm⁻², and detection and quantification limits of 0.6 and 5 μM (S/N = 3), respectively.