Phosphorescent sensor approach for non-destructive measurement of oxygen in packaged foods: Optimisation of disposable oxygen sensors and their characterization over a wide temperature range

Phosphorescent oxygen sensors were evaluated for their suitability as a non-destructive method of measuring oxygen in packaged foods. Using phosphorescent phase measurements, characteristics of several types of disposable oxygen sensors were studied in order to optimize sensor chemistry, fabrication technology and performance. The optimal sensor was characterized in both the gas phase and in the liquid phase, over a temperature range of - 17 °C - +30 °C and oxygen concentrations between 0 and 21 kPa. Calibrations, analytical equations and temperature coefficients were obtained, which enabled accurate quantitation of oxygen and correction of optical measurements for sample temperature variations. For disposable sensor elements the resolution of the system at 22 °C was about ±0.02 kPa and ±0.5 kPa at 0 and 21 kPa oxygen respectively, and in continuous monitoring mode - ±0.0054 kPa and ±0.081 kPa oxygen, respectively. Results of the use of the oxygen sensors in food packaging applications and practical recommendations are presented.