OXYGEN OPTRODE FOR USE IN A FIBEROPTIC GLUCOSE BIOSENSOR

An optical fiber oxygen sensor, based on the dynamic quenching of the luminescence of tris(1,10-phenanthroline)-ruthenium(II) cation by molecular oxygen, is presented. The complex Is adsorbed onto silica gel, incorporated in a silicone matrix possessing a high oxygen permeability, and placed at the tip of the optical fiber. Oxygen has been monitored continuously In the 0–750 Torr range, with the detection limit being as low as 0.7 Torr. The device has been applied to the development of a fast responding and highly sensitive fiberoptic glucose biosensor based on this highly sensitive oxygen transducer. The sensor relates oxygen consumption (as a result of enzymatic oxidation) to glucose concentration. The enzyme is immobilized on the surface of the oxygen optrode; carbon black Is used as an optical isolation In order to prevent ambient light and sample fluorescence to interfere. Measurements have been performed In a flow-through cell in air-equllibrated glucose standard solutions of pH 7.0. The effects of enzyme immobilization procedures (including enzyme immobilization on carbon black) as to response times (around 6 min), analytical ranges (0.06-1 mM glucose), reproducibility in sensor construction, and long-term stability have been studied as well. © 1990, American Chemical Society. All rights reserved.