HIGHLY SELECTIVE MEMBRANE-FREE, MEDIATOR-FREE GLUCOSE BIOSENSOR

Highly selective amperometric glucose sensors based on rhodium-dispersed carbon paste/glucose oxidase electrodes are described. The dispersed rhodium particles exhibit efficient and preferential electrocatalytic activity toward the liberated peroxide species and allow cathodic detection of the glucose substrate at -0.10 V, with no interference from easily oxidizable constituents. Such operation thus eliminates the need for interferant-eliminating enzyme layers, permselective membrane barriers, or artificial electron mediators, hence greatly simplifying the sensor design and fabrication. The sensor selectivity is illustrated in the presence of physiological levels of ascorbic acid, uric acid, acetaminophen, salicylic acid, tyrosine, urea, galactose, and glutathione. Attractive dynamic properties and high sensitivity are also achieved in the absence of membrane barriers. A stable response is observed over several months.