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Application of a Poly(hexafluoropropyl-co-tetrafluoroethylene) Thin-Film Architecture for Aqueous O2 Quantification

Volume 49, Number 12 (Dec. 1995) Page 1809-1814

Li, Ming; Pacholski, Michaeleen L.; Bright, Frank V.

Compared to electrochemical methodologies, detection and quantification of O2 with optical means has been regarded as more advantageous. Among the optical approaches that have been exploited, fluorescence quenching schemes have attracted significant attention. More recently, several authors have used time-resolved fluorescence in concert with quenching schemes to sense O2. We report a new quenching-based architecture to detect dissolved O2 in water. The system is composed of a fluoropolymer film, namely poly(hexafluoropropylene-co-tetrafluoroethylene) (FEP), that has been subjected to a radio-frequency glow discharge plasma to introduce -OH groups, modified further with aminopropyltriethoxysilane (APS) to produce an aminated surface, and subsequently reacted with an activated pyrene (Py) residue to form FEP-APS-Py. In a sample cell configuration this system exhibits a sensitivity to aqueous O2 as high as 863 ± 28 M-1 and a detection limit on the order of 10 μM O2. If β-cyclodextrin is added to the aqueous solution, the sensitivity to O2 is enhanced further. Slow time-dependent reconfiguration of the FEP-APS-Py surface is the major drawback of this system.