Luminescence optical oxygen sensors , utilize the principles of luminescence quenching by oxygen molecules to provide precise and reliable gas concentration measurements. This technology is highly valued for its non-invasive nature and versatility in various monitoring environments.
Principle of Operation
Luminescence optical sensing operates based on the quenching of phosphorescent light by oxygen. A luminescent material, typically a special dye, is excited by a light source, usually an LED. In the presence of oxygen, the excited dye molecules interact with oxygen, which affects their light emission properties. The degree of this interaction is directly related to the concentration of oxygen, with more oxygen leading to faster quenching and shorter emission lifetimes. This change in the luminescence properties is detected and converted into an oxygen concentration measurement.
Design and Components
- 1. Luminescent Dye: The core of the sensor, usually embedded in a gas-permeable polymer that interacts with oxygen.
- 2. Light Source: LEDs are commonly used to excite the luminescent dye.
- 3. Detector: A photodetector measures the intensity and decay time of the emitted light, which varies inversely with the oxygen concentration.
Advantages
- Non-Invasive and Non-Consumptive: This technology does not consume oxygen and does not alter the properties of the gas, making it suitable for a wide range of applications, including those where gas samples are small or need to be preserved such as medical gases or biological research applications.
- High Sensitivity and Selectivity: The quenching measurement technique combined with optical detection provides a high degree of sensitivity, fast measurement response while being selective to oxygen, minimizing interference from other gases.
- Compact Sensors for Seamless Integration: These sensors are physically small and low power making them easy to integrate into instrumentation.
Applications
Luminescence optical sensors are widely used in areas where traditional electrochemical or paramagnetic sensors may not be suitable:
- Biotechnology and Pharmaceutical: Monitoring oxygen in bioreactors and during the production of pharmaceuticals where contamination must be avoided.
- Medical: measurement of oxygen being presented to patient in critical or respiratory care
- Packaging and Food Industry: Checking oxygen levels in modified atmosphere packaging to ensure product freshness and longevity.
With their ability to operate without consuming or altering the sample, luminescence optical oxygen sensors are an essential tool in industries where non-invasive and interference-free measurement is critical. Their robustness, coupled with low maintenance needs, makes them an excellent choice for applications with low gas flow and delicate applications where sample integrity is paramount.