Chemiluminescence is the production of light as a direct result of a chemical reaction. These sensors are designed to react with specific chemicals of interest. Once reacted, light is emitted, and the detector will identify the presence of light. Sensors based on this technology have a detector that is identifying the presence of the emission of light, not the identification of a specific chemical. The sensors chemical selectivity and ability to avoid false positives is dependent on two aspects:
- The design of the chemiluminescence reagents, do they react with chemicals other than the chemicals they were designed to react with?
- The detector (most likely a photomultiplier tube), how well does it specify the wavelengths of the emitted light? If different chemicals are reacting with the chemiluminescence reagent, they will most likely produce light with a different wavelength than the chemical of interest would. Can the detector differentiate between them?
Advantages: Small and inexpensive. The components are typically replaceable if they get contaminated or spoiled.
Limitations: Typically have a very limited analyte list. Sensor may react with similar chemicals. As the reaction continues, the sensor is consumed, and will eventually need to be replaced.