Real-time direct electrochemical sensing of ascorbic acid over rat liver tissues using RuO₂ nanowires on electrospun TiO₂ nanofibers

This paper reports that the high electrocatalytic activity of RuO₂ nanowires grown on electrospun TiO₂ nanofibers for the oxidation of l-ascorbic acid (AA); and the application of these materials for direct selective sensing of AA in complex samples. Compared to bare glassy carbon (GC) electrode, RuO₂ nanowires on TiO₂ nanofibers-loaded GC electrode facilitates the oxidation of AA most drastically among the tested species: AA, 4-acetamidophenol (AP), dopamine (DA), uric acid (UA), and glucose. The amperometric response of RuO₂ nanowires on TiO₂ nanofibers at the applied potential of 0.018V (vs. SCE) exhibits high sensitivity (268.2±3.7μAmM^-1cm^-2, n=5), low detection limit (<1.8μM), great linearity, reasonable stability, and exclusive selectivity over AP, DA, glucose and UA at their physiological levels. In differential pulse voltammetry, it is verified that the potential resolution of RuO₂ nanowires on TiO₂ nanofibers is able to differentiate AA, DA, UA, and AP one from the others. In addition, as prepared RuO₂ nanowires on TiO₂ nanofibers are successfully applied for direct and selective AA measurements in commercial vitamin samples and for the real-time direct analysis of AA generated from living rat liver tissue in vitro.