Rapid and highly sensitive MnO_x nanorods array platform for a glucose analysis

A Mn₂O₃ nanorod array has been successfully prepared by using simple pulse-reverse electrodeposition that was then followed by transformation to a higher MnO_x oxidation state via electrochemical oxidation. The surface morphology and composition of the MnO_x nanorods was verified via scanning electron microscopy and X-ray photoelectron spectroscopy. The MnO_x nanorod array exhibits excellent electrocatalytic activity toward glucose oxidation under alkaline conditions and these properties were confirmed by using cyclic voltammetry, electrochemical impedance spectroscopy and chronoamperometry. The structure of the MnO_x nanorod array not only provides a large surface area, but also facilitates electron transfer and mass diffusion. The optimum oxidation time was determined to be 30 min, at which the MnO_x glucose sensor demonstrated a sensitivity at 811.8 μA mM^-1, which is the highest among the various types of MnO_x-based sensors that have been reported so far. Moreover, it also exhibited an excellent long-term stability and a good selectivity in the presence of interferents, such as ascorbic acid, dopamine, uric acid, urea, and aspartic acid. The practical applicability of MnO_x sensor was also studied by detecting glucose in human serum, in which it demonstrated an excellent selectivity and reliability.