Luminescence-Based Optical Fiber Chemical Sensors

A scheme for the simultaneous determination of temperature and analyte concentration for application in luminescence-based chemical sensors is proposed. This scheme is applied to an optical oxygen sensor, which is based on the quenching of the fluorescence of a ruthenium complex. Temperature measurement is performed using the excitation radiation and an absorption long-pass filter. Preliminary results are presented that show the viability of an oxygen measurement that is independent of temperature and optical power level. The possibility of self-referenced temperature measurements with semiconductor nanoparticles is also investigated. In order to optimize the sensor design, several different optical fiber probe geometries for oxygen sensing are tested and compared, including different methods of coupling radiation into the optical fiber system. Polyvinyl alcohol (PVA) and polyacrylamide membranes are tested as supports for sensor immobilization in fiber-optical pH sensing devices in aqueous solution. Some results are presented that show the feasibility of using fiber-optical pH indicators for remote monitoring.