GRAPHITE-TEFLON ENZYME ELECTRODE

The fabrication and performance of graphite-Teflon-enzyme electrodes a re described. The new bulk-modified composite enzyme electrodes couple the advantages of renewable (polishable) surfaces, mechanical rigidit y, fast response, and favorable signal-to-noise characteristics. The n ew fabrication strategy is illustrated for the immobilization of horse radish peroxidase and glucose oxidase, in connection with measurements of peroxide species and glucose, respectively. The incorporation of a ferrocene mediator to yield a reagentless device is also illustrated. Flow injection measurements of hydrogen peroxide with the graphite-Te flon-peroxidase detector are carried out at 120 samples/hour, to yield a detection limit of 2.5 x 10(-6) M and a relative standard deviation of 2%. Applicability to organic-phase biosensing is illustrated.