A Surface Modified Carbon Nanotube Fiber as a Microelectrode for the pH-Dependent Electrochemical Detection of...

A pH-dependent electrochemical sensor based on nickel-cobalt oxide modified carbon nanotube fiber (NiCo-O@CNTF) has been fabricated via a simple electrochemical approach and utilized in the nonenzymatic detection of ascorbic acid (AA) with varying pH. Scanning electron microscopy (SEM), energy-dispersive electron microscopy (EDX), Raman, and FTIR were utilized to investigate the structural morphologies, elemental mapping, and electronic vibrational modes within the modified fiber (NiCo-O@CNTF) and revealed the successful fabrication of the electrode. Electrochemical characterization, including cyclic voltammetry and chronoamperometry, exhibited an enhanced anodic response in buffer solutions (varying pH), achieving a high sensitivity of 62.39 μA cm^-2 mM^-1, a low detection limit of 16 μM, and a rapid response time of 5 s at pH 8.0. These results highlight NiCo-O@CNTF as a flexible and disposable microelectrode platform for wearable AA sensing applications.