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Different Ru complexes were used in an organically modified sol-gel (ormosil) sensing film to character their quenching behaviors to oxygen. The sensing film with tris-(4,7-diphenyl-1, 10-phenanthroline) ruthenium(II) [Ru(dpp)(2+)3] as an indicator was selected because of its characteristics with high quenching efficiency, fast response time, high luminescence intensity and long-term stability. The quenching behavior of the sensing film greatly depended on the content of dimethyldimethoxysilane (DiMe-DMOS) in ormosil because DiMe-DMOS changed the polarity of sensing film. A home-made fluorescence quenching system was set up for oxygen determination based on a blue LED (lambda max = 460 nm ) as an exciting light source. Th e response time was 30 s from saturatednitrogen to oxygen in water, and 90 s from saturated oxygen to nitrogen.

A new kind of organically modified sol-gel (ormosil) as a matrix for oxygen-sensitive sensor, in which dimethyldimethoxysilane was selected as an organic modifier in the precursor is described. The fluorescent behaviors of different ruthenium complexes in solution and ormosil film were studied. The sensing film with different kind ruthenium complex as an indicator developed in this paper was characterized in terms of efficiently quenched by oxygen. A new ormosil provides a more desirable environment for oxygen response through increasing film hydrophobicity by the content of the nonbridging Si-CH3 groups has been discussed. The sensing film with tris-(4,7-diphenyl-1,10-phenanthroline) ruthenium(II) as an indicator is selected because of its characteristic with high quenching efficiency, fast response time, high luminescence intensity and long-term stability.