Oxygen-sensitive reverse-phase optode membrane using silica gel-adsorbed ruthenium(II) complex embedded in gelatin film

An oxygen-sensitive reverse-phase optode membrane consisting of tris(4,7-diphenyl-1,10-phenanthroline)ruthenium(II) ditetrakis(4-chlorophenyl)borate adsorbed on silica gel and embedded in a gelatin film has been successfully fabricated and used to continuously monitor dissolved oxygen in organic solvents. The optode membrane shows a very strong and stable pink emission when excited by blue light and it is efficiently quenched by molecular oxygen. The response of the sensor displays typical nonlinear Stern-Volmer behaviour when the dissolved oxygen concentration in organic solvents is at high levels. But the sensor is most sensitive at lower oxygen levels and is linear in the range 0-1.14, 0-2.10 and 0-0.53mM for dissolved oxygen in acetone, dimethyl formamide and toluene, respectively. The t₉₅ response times of the sensor are 10s on going from nitrogen-saturated toluene to air-saturated toluene and 22s on going from air-saturated toluene to nitrogen-saturated toluene. The sensor has good reproducibility, high photostability, no hysteresis, good precision and long lifetime. Copyright (C) 1999 Elsevier Science B.V.