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 (CoO(x)(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 CoO(x)(OH)(y) film. Cyclic voltammetry (CV) was used to investigate the electrochemical properties of PA on CoO(x)(OH)(y)/ITO in order to select the optimal potential for the chronoamperometric detection of PA. It was found that the CoO(x)(OH)(y)/ITO electrode served as an excellent PA sensor with a linear detection range of 1.00 mu M to 1.91 mM, a detection limit of 0.55 mu M, and a high sensitivity of 417.1 mu A mM(-1) cm(-2). Moreover, the response time of CoO(x)(OH)(y)/ITO to PA is less than 10s, which is the shortest for PA detection reported in literature using electrochemical method. These properties and the high stability of CoO(x)(OH)(y)/ITO made it a good candidate for developing electrochemical enzyme-free PA sensing device. (C) 2011 Elsevier Ltd. All rights reserved.