Amperometric glucose biosensor based on chitosan with improved selectivity and stability

A rapid, simple method for fabricating glucose biosensors have been proposed for the efficient immobilization of enzymes and elimination of interferences at the same time. By using a single biopolymer chitosan on Pt electrode, first positively charged polyelectrolyte was constructed through glutaraldehyde as a cross-linking agent so that this kind of chitosan modified film can eliminate interference of possible electroactive compounds. Then another layer of chitosan was applied to immobilize enzyme glucose oxidase. The biosensor was operated at +0.600 V with a short response time (< 8 s). The biosensor was free of typical interference, and cost-effective. The potential responses of the glucose sensor increase with the glucose concentration over the concentration range 0.05-15 mM, with high sensitivity (21 mA M-1 cm(-2)), and the detection limit is 10 mum. Furthermore, the biosensor exhibited long-term stability, and good reproducibility. The biosensors were applied to determination of glucose in beverage drinks. (C) 2004 Elsevier B.V. All rights reserved.