Optical Oxygen Sensing Based on the Luminescence Quenching of Europium(III) Complex Immobilized in Fluoropolymer Film

New optical oxygen sensors based on the luminescence intensities of four different europium(III) complexes, ((1,10-phenanthroline)tris(thenoyltrifluoroacetonato)europium(III) complex ([Eu(tta)3phen]), tris(thenoyltrifluoroacetonato)europium(III) dihydrate ([Eu(tta)3]·2H2O), tris(1,1,1-trifluoro-5,5-dimethyl-2,4-hexanedionato)europium(III) complex ([Eu(pta)3]·2H2O) and tris(1,1,1,2,2,3,3-heptafluoro-7,7-dimethyl-4,6-octanedionato)europium(III) complex ([Eu(fod)3]·2H2O)) immobilized in poly(styrene-co-2,2,2-trifluoroethyl methacrylate) (poly-(styrene-co-TFEM)) films were developed. The luminescence intensity of the europium(III) complex films decreased with increasing the oxygen concentration. Stern-Volmer plots of the europium(III) complex films exhibited considerable linearity. The KSV values of [Eu(tta)3phen], [Eu(tta)3]·2H2O, [Eu(pta)3]·2H2O and [Eu(fod)3]·2H2O in films were estimated to be 0.015, 0.005, 0.002 and 0.003 %-1, respectively. The large KSV value of the [Eu(tta)3phen] film was obtained compared with the other europium(III) complexes. The response times of the europium(III) complex films are 6.7 s for [Eu(tta)3phen], 6.7 s for [Eu(tta)3]·2H2O, 6.6 s for [Eu(pta)3]·2H2O and 7.6 s for [Eu(fod)3]·2H2O on going from argon to oxygen and 7.0 s for [Eu(tta)3phen], 7.5 s for [Eu(tta)3]·2H2O, 8.1 s for [Eu(pta)3]·2H2O and 8.6 s for [Eu(fod)3]·2H2O on going from oxygen to argon, respectively. A highly sensitive oxygen sensor using [Eu(tta)3phen] immobilized in poly-(styrene-co-TFEM) film has been developed.