Oxygen sensing system using triplet-triplet reflectance of zinc porphyrin immobilized in polymer membrane studies by laser flash photolysis

A new oxygen sensing system based on the photoexcited triplet stare quenchi ng of photosensitizers immobilized in polymer matrices has been developed b y laser flash photolysis. As the photosensitizers, zinc tetraphenylporphyri n (ZnTPP), zinc tetrakis(pentafluorophenyl) porphyrin, (ZnTFPP), zinc etiop orphyrin (ZnEtioP), zinc octaethylporphyrin (ZnOEP), or zinc tetrabenzoporp hyrin (ZnTBP) are used. As the polymer matrices, polystyrene (PS), polyviny lchloride (PVC), polymethylmethacrylate (PMMA) and polydimethylsiloxane (GP 197) are used. Among the above systems, ZnTFPP immobilized in PS membrane i s the most suitable for oxygen sensing; a large Stern-Volmer constant (0.61 1 Torr(-1)) and good stability against irradiation were obtained. (C) 2000 Elsevier Science S.A. All rights reserved.