Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
743480 | Sensors and Actuators B: Chemical | 2009 | 6 Pages |
Using calcium carbonate nanoparticles as enzyme immobilization matrix, the developments of xanthine biosensor were achieved by both electrooxidation and electroreduction of the enzymatic-generated hydrogen peroxide based on xanthine oxidase (XnOx) and horseradish peroxidase (HRP). Amperometric detection of xanthine was evaluated by holding the modified electrode at 0.55 and −0.05 V (versus SCE), for XnOx/Nano-CaCO3 and XnOx/HRP/Nano-CaCO3, respectively. The linear dynamic ranges of anodic and cathodic detections of xanthine were between 2 × 10−6 to 2.5 × 10−4 M and 4 × 10−7 to 5 × 10−5 M, respectively. The detection limits were determined to be of 2 × 10−6 and 1 × 10−7 M with anodic and cathodic processes, respectively. At lower working potential, XnOx/HRP/Nano-CaCO3/GCE bienzymatic system exhibited excellent selectivity; the bienzyme electrode was inert towards ascorbic and uric acid present. Moreover, the permeability of enzyme/Nano-CaCO3 was evaluated by the use of rotating disk electrode voltammetry.