The multi fiber optode (MuFO): A novel system for simultaneous analysis of multiple fiber optic oxygen sensors

Abstract

A novel system for simultaneous operation of multiple fiber optic oxygen sensors (optodes) is described and characterized. The system is based on an array of one hundred several meter long freely positionable polymer optical fibers with an oxygen sensitive luminophore immobilized at the sensing end of each fiber. The opposite ends of the fiber optodes are fixed in a 10×10 matrix and placed in front of a CCD camera and a LED-light source. Oxygen measurements are conducted by simultaneous excitation of all optodes with the LEDs followed by simultaneous lifetime imaging of the one hundred fiber optodes with the camera. Automated digital image analysis allows for calculation of the luminescence lifetime of each fiber optode individually, which can be converted into oxygen partial pressures. The multi fiber optode (MuFO) system had an overall accuracy of 1% when tested at fixed temperatures and 5% when calibrated over a temperature range from 2 to 32°C and an average 90% response time of 16s. The system had an average precision of 0.2% air saturation and an average detection limit of 0.1% air saturation.The MuFO system can be adapted for trace level oxygen measurements and for other analytes such as pH, CO2, temperature and heavy metal ions by using different luminophore coatings and imaging approaches.