A glucose sensor based on graphite paste modified with tetracyanoquinodimethane

667-672An arnperometric enzyme electrode for glucose based on glucose oxidase (GOD) incorporated into a graphite paste modified with tetracyanoquinodimethane (TCNQ) shows long term stability (65% loss of initial response after 26d). The sensor provides a linear response to glucose over a wide concentration range (linear=0.5-100 mmol and non-linear = 100-300 mmol). The response time of the sensor is 15-50 sec and the detection limit is 0.5 mmol. Stable response to the substrate is obtained over a period of several weeks upon storage in 0.1M phosphate buffer (pH 7.0) at room temperature. Data are presented on the influence of binder composition, anodic potential, pH, and temperature upon the electrode. A qualitative approach to the kinetic analysis of the electrode response is reported based on cyclic voltammetric data. Comparison of the electrode response is made with the data obtained using ferrocene-mediated graphite paste glucose sensor and it is concluded that TCNQ has better compatibility with the graphite paste than ferrocene derivatives though ferrocene is more efficient mediator than TCNQ