HIGHLY SELECTIVE AND SENSITIVE AMPEROMETRIC BIOSENSING OF GLUCOSE AT RUTHENIUM-DISPERSED CARBON-PASTE ENZYME ELECTRODES

The selectivity and sensitivity of glucose measurements at carbon-past e based amperometric biosensors are greatly enhanced through the use o f ruthenium-dispersed graphite particles. The improved performance is attributed to the substantial lowering of the overvoltage for the redu ction of the hydrogen peroxide product. Hence. cathodic measurements o f glucose can be carried out at an optimal potential range (-0.15 to 0.20 V). Contributions from easily oxidizable substances (e.g. acetami nophen, ascorbic and uric acids) are eliminated, without the need for mediators or membrane barriers. The electrocatalytic action of the rut henium sites results also in a substantially improved sensitivity. A f ast flow injection operation is illustrated.