OPTOSENSING OF D-GLUCOSE WITH AN IMMOBILIZED GLUCOSE-OXIDASE MINIREACTOR AND AN OXYGEN ROOM-TEMPERATURE PHOSPHORESCENCE TRANSDUCER

Glucose oxidase was immobilized covalently on a nylon membrane and the oxygen consumption was followed via the changes in the room-temperature phosphorescence (RTP) of an oxygen-sensitive metal chelate whose RTP is quenched dynamically by molecular oxygen. The metal chelate was immobilized on an anion-exchange resin and packed into a conventional flow-through cell. As result of the glucose oxidation in the presence of the enzyme, a certain amount of oxygen was consumed, which in turn was indicated by the RTP of the chelate. Measurements were made in flowing air-saturated solutions containing 0.1 M acetate buffer (pH 5.9). The system is linear for 0.5-2.5 mM glucose with a relative standard deviation of 1.6% at 2 mM (ten measurements). The detection limit is 8 x 10(-5) M and the application of the system to glucose determination in serum and beverages is demonstrated.