Direct electrochemical detection of pyruvic acid by cobalt oxyhydroxide modified indium tin oxide electrodes

An enzyme-free electrode was fabricated by anodic electrodeposition of cobalt oxyhydroxide film on an ITO electrode (CoOx(OH)y/ITO) for direct electrochemical detection of pyruvic acid (PA) in solution. Scanning electron microscopy (SEM) and atom force microscopy (AFM) were employed to characterize the morphology of CoOx(OH)y film. Cyclic voltammetry (CV) was used to investigate the electrochemical properties of PA on CoOx(OH)y/ITO in order to select the optimal potential for the chronoamperometric detection of PA. It was found that the CoOx(OH)y/ITO electrode served as an excellent PA sensor with a linear detection range of 1.00 μM to 1.91 mM, a detection limit of 0.55 μM, and a high sensitivity of 417.1 μA mM−1 cm−2. Moreover, the response time of CoOx(OH)y/ITO to PA is less than 10 s, which is the shortest for PA detection reported in literature using electrochemical method. These properties and the high stability of CoOx(OH)y/ITO made it a good candidate for developing electrochemical enzyme-free PA sensing device.