Noncovalently functionalized water-soluble multiwall-nanotubes through azocarmine B and their application in nitric oxide sensor

A new noncovalent approach for the dissolution of MWNTs in water by azocarmine B (ACB) is reported. Through a simple electro-polymerization procedure, a novel electrochemical NO sensor based on water-soluble MWNTs and polyazocarmine B (PACB) nanofilm electrode was prepared, which showed excellent electrocatalytic activity towards the oxidation of nitric oxide (NO). The oxidation current linearly increased with the nitric oxide concentration in the range of 2.2 × 10⁻⁷–1.2 × 10⁻⁴ mol L⁻¹ with a low detection limit of 2.8 × 10⁻⁸ mol L⁻¹. The sensor has the merit of good stability, reproducibility, high sensitivity and selectivity, and it can be used to monitor NO released from rat liver cells effectively.