It is well known that the adenine derivatives, NAD+ and its reduced form (NADH) are the key central charge carriers in living cells. Electroreduction of nicotineamide adenine dinucleotide ion (NAD+) to the enzymatically active compound NADH is of interest. Carbon nanotubes are new kinds of porous nanostructure carbon materials, which are promising as immobilization substances because of their significant mechanical strength, high electrical conductivity, high surface area, good chemical stability, as well as relative chemical inertness in most electrolyte solutions and a wide operation potential window. They can be used to promote electron transfer reactions when used as electrode materials in electrochemical devices, electrocatalysis and electroanalysis processes. Immobilization of molecules and biomolcules on CNTs has been pursued in the past, motivated by the prospects of using nanotubes as new types of sensor and biosensors. Cyclic voltammetry was used for immobilization of nicotineamide adenine dinucleotide ion (NAD+) onto glassy carbon electrode modified with single wall carbon nanotubes. The modified electrode was transferred into various aqueous acidic and alkaline solutions (pH 1-12), the stable pH dependent redox system was observed at wide pH range. The heterogeneous electron between NAD+ and CNTs immobilized onto electrode surface. The modified electrode exhibited excellent electrocatalytic activity for iodate and periodate reduction at reduced overpotential In addition the modified electrode shows electrocatalytic oxidation for hydrazine and hydroxylamine oxidation in natural aqueous solutions.
