Glucose sensing by a carbon-paste electrode containing chitin modified with glucose oxidase

As one application for chitin, the development of a glucose sensor was attempted at a carbon paste electrode containing platinum powder and chitin powder with glucose oxidase. Immobilization of the enzyme is based on an electrostatic interaction between the protonated acetylamide group of the chitin and functional groups having a negative charge on the enzyme. Glucose oxidase was simply immobilized on the chitin in 0.1 M acetate buffer (pH 5.0). An oxidation peak of H₂O₂ produced from the enzyme reaction was observed at about +0.60 V (vs. Ag | AgCl) in 0.1 M acetate buffer (pH 6.2). The calibration curve of glucose was linear in the range from 3 × 10^-6 to 4 × 10^-4 M. This method was applied to determination of glucose in a sports drink.