Ultra micro biosensors using platinized carbon fiber electrode integrated counter electrode

An integrated ultra micro biosensor was constructed with a platinized carbon fiber disk (PCD) electrode with a 7- mu m diameter and a platinum thin film (PTF) counterelectrode fabricated on the glass capillary tube. By platinization, the electrode activity of the carbon fiber was greatly improved. In order to obtain stable response, pulse potential was applied to hydrogen peroxide measurement. The PTF counterelectrode showed good stability and could be used as a substitute for the silver-silver chloride electrode. Since the integrated PCD electrode showed good characteristics as a hydrogen peroxide sensor, glutamate oxidase was immobilized onto the tip of the PCD electrode and an ultra micro glutamate sensor was constructed. The sensor showed stable response to glutamate, and the response time was within 12 s. The calibration range for glutamate measurement was 50 to 800 mu M.<>