Development of a Dissolved Oxygen Sensor for Commercial Applications

The gold nanoparticles (GNP) and functionalized carbon nanotube (f-CNT) film (GNP-f-CNT) was prepared on glassy carbon electrode (GCE) by multiple scan cyclic voltammetry. The electrochemical measurements and surface morphology of the as prepared films were studied using field emission scanning electron microscopy (FE-SEM), electrochemical impedance spectroscopy (EIS) and X-ray diffraction (XRD). The proposed film were demonstrated for the determination of dissolved oxygen using cyclic voltammetry and rotating disk electrode voltammetry. The electrocatalytic reduction of dissolved oxygen at bare GCE, f-CNT, GNP and GNP-f-CNT modified electrodes, were determined in 0.1 M pH 7 phosphate buffer solution. The dissolved oxygen electrochemical sensor exhibits a well linear response range (from 0 to 50 mg/L, R2 = 0.9988), lowest detection limit (0.1 mg/L), high sensitivity (196.5 μA L mg-1 cm-2) and the relative standard deviation (RSD) for determining dissolved oxygen (n = 3) was 3.8%. For the determination of dissolved oxygen, the GNP-f-CNT film modified GCE shows on lowest over-potential at -0.17 V. In addition, the proposed film also exhibit excellent stability and specificity.