New composite modified carbon microfibers for sensitive and selective determination of physiologically relevant concentrations of nitric oxide in solution

In this study, we have prepared nitric oxide (NO) microsensors using four c ombinations of nickel porphyrin (NiP), o-phenylenediamine (o-PD), n-phenyle nediamine (m-PD), resorcinol and Nafion based layers to modify the surface of 8 mu m diameter carbon fiber electrodes. We have compared the performanc es of the obtained composite microsensors (NiP/Nafion, Nafion/o-PD, Nafion/ (m-PD + resorcinol), and NiP/Nafion/o-PD, respectively) in our home operati ng conditions. Our results indicate that Nafion/o-PD and Nafion/(m-PD + res orcinol) microsensors are capable of detecting NO very selectively against nitrites, ascorbate, L-arginine, serotonine and xanthine. But these microse nsors have a poorer sensitivity to NO than the NiP/Nafion/o-PD microsensor. If selectivity is not a concern, NiP/Nafion, Nafion/o-PD and NiP/Nafion/o- PD microsensors are the most sensitive to NO concentrations as low as 40 nm ol L-1.