A Tubular Graphite-Epoxy Electrode Incorporating horseradish Peroxidase as a Potentiometric Sensor for Hydrogen Peroxide

A novel potentiometric peroxidase enzyme sensor based on a tubular graphite‐epoxy design is reported for the determination of hydrogen peroxide in an FIA system. The sensor was formed from horseradish peroxidase (40 mg), graphite (240 mg) and epoxy (780 mg). Hydrogen peroxide, injected into pH 7,0.05 M phosphate buffer at 26°C, was determined with a linear slope of 45.6 mV/decade in the concentration range 7.5 × 10−7 to 5.0 × 10−5 M. Acceptable reproducibility of 1.2% relative standard deviation was obtained in the flow injection analysis. The advantages of this sensor are low cost, simple electronic circuit design and better selectivity than amperometric sensors and a detection limit comparable with other methods. Copyright © 1995 VCH Verlagsgesellschaft mbH