A glucose oxidase sensor based on screen-printed carbon electrodes modified by polypyrrole

Abstract

A disposable amperometric biosensor for detecting blood glucose has been developed. The sensor is based on a screen-printed electrode prepared by electrochemical polymerization of pyrrole with glucose oxidase (GOD) and LiClO₄ dopants. In citric acid buffer (pH5.0), GOD with negative charges is immobilized within electropositive polypyrrole matrices onto a carbon electrode surface. Afterward, the electron transfer mediator, potassium ferricyanide is immobilized by adsorption. Experimentally the compositions of pyrrole, LiClO₄ and potassium ferricyanide are optimized. Amperometry is used for the determination of glucose concentration. Four microliters of glucose solution is needed for one test, and the response time of the sensor is 70s. The amperometric response of the enzyme electrode is linear in the range of 1-30 mM.