Nitric Oxide Permselectivity in Electropolymerized Films for Sensing Applications

The presence of biological interferents in physiological media necessitates chemical modification of the working electrode to facilitate accurate electrochemical measurement of nitric oxide (NO). In this study, we evaluated a series of self-terminating electropolymerized films prepared from one of three isomers of phenylenediamine (PD), phenol, eugenol, or 5-amino-1-naphthol (5A1N) to improve the NO selectivity of a platinum working electrode. The electrodeposition procedure for each monomer was individually optimized using cyclic voltammetry (CV) or constant potential amperometry (CPA). Cyclic voltammetry deposition parameters favoring slower film formation generally yielded films with improved selectivity for NO over nitrite and L-ascorbate. Nitric oxide sensors were fabricated and compared using the optimized deposition procedure for each monomer. Sensors prepared using polyphenol and poly-5AlN film-modified platinum working electrodes demonstrated the most ideal analytical performance, with the former demonstrating the best selectivity versus nitrite. In simulated wound fluid, platinum electrodes modified with poly-5AlN films proved superior with respect to NO sensitivity retention and detection limit.