GLUCOSE SENSOR - POLYPYRROLE GLUCOSE-OXIDASE ELECTRODE IN THE PRESENCE OF PARA-BENZOQUINONE

Glucose oxidase (GOD) was entrapped in a polypyrrole film during the electropolymerization of a pyrrole solution containing PIPES buffer (pK(a) = 6.8), LiClO4 and sodium dodecylsulphate. We obtained homogeneous GOD/PPY films which adhere well to the electrode and exhibit a sensitive amperometric response in the presence of glucose solutions. The GOD/PPY electrode was used as a glucose sensor electrode in the presence of p-benzoquinone. The latter acts as a mediator for the electron transfer between GOD and the electrode. The potential applied for hydroquinone (H-2Q) oxidation (regeneration of benzoquinone) was 350 mV/sce. This potential is much lower than the potential required when oxygen is used as the electron acceptor. Kinetic considerations showed that the enzymatic reaction occurs mainly at the PPY/solution interface and within a small volume of the polymer near this interface.