To sense oxygen within a package, an OxyDot (O2xyDot®) is attached to the inside of the package. The dot is illuminated with a pulsed blue light from an LED. The blue light is absorbed by the dot and red light is emitted.
The red light is detected by a photo-detector and the characteristics of the fluorescence lifetime is measured. Different lifetime characteristics indicate different levels of oxygen within the package.
OxyDot (O2xyDot®) - Sensing Oxygen Within a Package: The OxySense® fiber optic reader-pen assembly contains both a blue LED and photodetector used to measure the fluorescence lifetime characteristics of an OxyDot (O2xyDot®) within a sealed container.
The oxygen measurement technique is based upon the fluorescence quenching of a metal organic fluorescent dye immobilized in a gas permeable hydrophobic polymer. The dye absorbs light in the blue region and fluoresces within the red region of the spectrum. The presence of oxygen quenches the fluorescent light from the dye as well as its lifetime. The quenching process is a purely collisional dynamic where the energy from the excited fluorescent dye is transferred to the oxygen molecule during a collision, hence, reducing the emission intensity as well as the fluorescent lifetime of the dye. Thus, the oxygen content of the enclosed space is not changed by the measurement process.
The change in the emission intensity and lifetime is related to the oxygen partial pressure and can be calibrated to determine the oxygen concentration. The measurement is passive, totally reversible and no oxygen is consumed in the process. The fluorescence lifetime is reduced due to the presence of oxygen; this change can be calibrated to make a powerful sensor that has a large dynamic range.
The Advantages of OxySense
- Non-destructive measuring technique
- Thousands of measurements per package
- Fast measurements (< .1 second)
- Accuracy at ambient, 5% of the reading
- Reproducibility is better than 1% (0.2% O2)
- Sterilization tested up to 150°C (1sp hr.), can withstand pasteurization
- Can be used in oil, water and air
- Independent of pH (2-12) and salt concentration
- No interference from other gases
No matter what your oxygen measurement or monitoring requirement, OxySense can provide an easy-to-use, efficient and economic solution. Contact us with your requirements and give us the opportunity to show you the OxySense Solution.