Emission based oxygen sensing approach with tris(2,2'-bipyridyl) ruthenium(II)chloride in green chemistry reagents: Room temperature ionic liquids

Room temperature ionic liquids doped with tris(2,2'-bipyridyl) ruthenium(II)chloride together with chemically and biochemically inert perfluoro chemicals (PFCs) have been used for the first time for optical O2 sensing purposes. The response to oxygen of the Ru complex in 1-methyl-3-butylimidazolium tetrafluoroborate (RTIL-I) and 1-methyl-3- butylimidazolium bromide (RTIL-II) has been evaluated in terms of sensitivity, stability, regeneration ability and response time. The response times were 2 and 5 s, respectively, and the signal changes were reversible. Better oxygen solubility, enhanced molar absorption coefficients and photostabilies were found for the RTILs. The stability the Ru complex in RTILs was tested over 12 months and it is when stored in the ambient air of the laboratory. © 2008 Springer-Verlag