title: Dual optical sensor for oxygen and temperature based on the combination of time domain and frequency domain techniques.
abstract: In measuring specific conditions in the real world, there are many situations where both the oxygen concentration and the temperature have to be determined simultaneously. Here we describe a dual optical sensor for oxygen and temperature that can be adapted for different applications. The measurement principle of this sensor is based on the luminescence decay times of the oxygen-sensitive ruthenium complex tris-4,7-diphenyl-1,10-phenanthroline ruthenium(III) [Rudpp] and the temperature-sensitive europium complex tris(dibenzoylmethane) mono(5-amino-1,10-phenanthroline)europium(III) [Eudatp]. The excitation and emission spectra of the two luminophores overlap significantly and cannot be discriminated in the conventional way using band pass filters or other optical components. However, by applying both the frequency and time domain techniques, we can separate the signals from the individual decay time of the complexes. The europium complex is entrapped in a poly(methyl methacrylate) (PMMA) layer and the ruthenium complex is physically adsorbed on silica gel and incorporated in a silicone layer. The two layers are attached to each other by a double sided silicone based tape. The europium sensing film was found to be temperature-sensitive between 10 and 70°C and the ruthenium oxygen-sensitive layer can reliably measure between 0 and 21% oxygen.
authors.affiliation: Center of Advanced Sensor Technology, Department of Chemical and Biochemical Engineering, University of Maryland Baltimore County, 1000 Hilltop Circle, Baltimore, MD 21250, USA.
authors.forename: Hung
authors.initials: H
authors.lastname: Lam
authors.forename: Govind
authors.initials: G
authors.lastname: Rao
authors.forename: Joana
authors.initials: J
authors.lastname: Loureiro
authors.forename: Leah
authors.initials: L
authors.lastname: Tolosa
mesh_terms: D002623:Chemistry Techniques, Analytical / Q000295:instrumentation*; D008163:Luminescent Measurements; D055620:Optical Phenomena; D010100:Oxygen / Q000032:analysis*; D013696:Temperature; D013997:Time Factors
chemical_list: D010100:Oxygen