A new conducting polymer glucose sensor based on polythianaphthene

A glucose biosensor has been developed by entrapment of glucose oxidase in a polythianaphthene film formed onto a platinum surface. Glucose has been measured by H2O2 detection at +400 mV (vs. SCE). Electrochemical kinetic constants for the enzyme electrode have been calculated and indicated that in the unsaturated region the rate limiting step is the diffusion of the substrate through the polymer. The biosensor exhibited a linear response in the range 0.05-7.4 mmol/L with a response time of 30-60 s and a relative standard deviation of 5.4%. The presence of the film onto the electrode prevents the oxidation of interfering agents such as ascorbic and uric acid. The use of additional polycarbonate membranes onto the electrode surface extended the linearity of the response allowing the probe to be used in blood glucose analysis. The amount of glucose in two control sera was measured using the biosensor. Results correlated well with the glucose nominal values.