Département de chimie moléculaire

Using calcium carbonate nanoparticles as enzyme immobilization matrix, the developments of xanthine biosensor were achieved by both electrooxidn. and electroredn. of the enzymic-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 (vs. SCE), for XnOx/Nano-CaCO3 and XnOx/HRP/Nano-CaCO3, resp. 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, resp. The detection limits were detd. to be of 2 × 10-6 and 1 × 10-7 M with anodic and cathodic processes, resp. At lower working potential, XnOx/HRP/Nano-CaCO3/GCE bienzymic 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. [on SciFinder(R)]