POLYSTYRENE IMMOBILIZED IR(III) COMPLEX AS A NEW MATERIAL FOR OPTICALOXYGEN SENSING

The luminescence spectra of tris(phenylpyridine)iridium embedded in Am berlite (polystyrene adsorbent) have been measured under various O2/N2 mixtures (total pressure = 1 atm). It is shown that the Stern-Volmer plots are downward curved and that the curvature can be explained eith er by a two-site model or by a negative deviation from Henry's law. A curve fitting procedure cannot distinguish between the two models. Usi ng a frequency modulated blue LED and a fiber optic set-up, O2 partial pressure of 0.4 mbar could be detected. Oxygen can be determined at 2 00 mbar with a +/- 1.5% accuracy.