An intrinsic fiber optic environmental sensor has been developed for on-line monitoring of oxygen gas and dissolved oxygen (DO). In this O₂/DO sensor, a highly stable compound [Tris-(4,7-Diphenyl-1, 10-phenanthroline) Ruthenium (II) complex] is synthesized and selected as a chemical indicator for oxygen. A hybrid matrix is designed by a sol-gel process and used as a stable substrate for the immobilization of Ru compound. The microporous nature of the nondensified sol-gel coating, in which the photochemical dye is immobilized, provides a unique local structure that is environmentally stable and immune to photochemical bleaching and chemical leaching. The doped hybrid material is then coated on a porous optical fiber substrate used as the sensing component. The oxygen penetrates into the interconnective porous core and interacts with the immobilized Ru compound in which in-line dynamic luminescence quenching takes place. The use of Ru(ph2phen)3[2+] as a highly stable, reagent sensing indicator and also the use of the sol-gel coating technique for the immobilization and incorporation of Ru compound to porous core optical fibers have resulted in the development of an intrinsic O₂/DO sensor with high sensitivity, reproducibility, and long-term stability.

Date Published: 10 March 1994
PDF: 17 pages
Proc. SPIE 2068, Chemical, Biochemical, and Environmental Fiber Sensors V, (10 March 1994); doi: 10.1117/12.170670

Published in SPIE Proceedings Vol. 2068:
Chemical, Biochemical, and Environmental Fiber Sensors V
Robert A. Lieberman, Editor(s)