Electrochemical generation of 1-amino-pyrene-4,5,9,10 tetrol on the MWCNT surface for low potential electrocatalytic NADH oxidation

We report the electrochemical activation of 1-aminopyrene (1-AP) on the surface of multi-wall carbon nanotubes (MWCNT) and investigated its electrochemical properties for NADH oxidation. Through the electrochemical oxidation, the 1-AP is restructured into a highly electroactive active 1-amino-pyrene-4,5,9,10 tetrol (1-APox) revealing reversible quinone/hydroquinone redox transitions. As a result, the functional hybrid nanostructure was obtained, which was then used to modify the glassy carbon electrode (GC). Atomic force microscopy (AFM) shows that 1-APox uniformly covers the surface of the MWCNT. Mass spectrometry (MS) was applied to confirm the structure of the resultant 1-APox. X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FT-IR) analysis indicates attachment of oxygen group due to electrochemical oxidation. The results obtained by cyclic voltammetry (CV) showed that MWCNT/1-APox revealed good reversibility of the resultant redox couple in aqueous buffered electrolytes. The modified GC/MWCNT/1-APox electrode exhibits remarkable electrocatalytic activity to oxidize NADH at a low potential. A limit of detection (LOD) of 0.08 μM and a limit of quantification (LOQ) of 0.23 μM have been established for an amperometric technique of NADH measurement based on its electrocatalytic approach. High electrocatalytic activity, high sensitivity, and easy preparation are benefits of the sensor.