Oxygen is sensed by measuring the decrease in fluorescence intensity of a fluorophore bound to the tip of an optical fiber. The sensor responds to the partial pressure of oxygen in gases, liquids and even viscous samples.
Used with Ocean Optics Fiber Optic Oxygen Sensors and custom probes, the MultiFrequency Phase Fluorometer (MFPF), manufactured by TauTheta, is a flexible platform for measurement of luminescence lifetime, phase and intensity. This frequency-domain luminescence monitor uses LED excitation and avalanche photodiode detection with filter-based wavelength selection for easy experimental set-up and control. The MFPF is especially useful for oxygen sensing applications where sensitivity to drift is important and where sample set-ups must be undisturbed for long periods of time. Because it utilizes phase-shift technology, it is invariant to fiber bending and stray light, has a wide dynamic range of optical intensity, and has low optical and electronic crosstalk as well as low drift and phase noise.
The MFPF is embedded with LED excitation sources and transmits light at ~475 nm to one leg of a QBIF600-VIS-NIR Bifurcated Optical Fiber Assembly. The bifurcated assembly connects to the oxygen sensor probe via a 21-02 SMA Splice Bushing. If the excited formulation at the probe tip encounters an oxygen molecule, the fluorescence signal decreases. The fluorescence is collected by the probe and is transmitted to the spectrometer via the other leg of the bifurcated assembly. OOISensors Software calculates partial pressure of the oxygen from this signal.