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Ammonia Detection by use of Near-Infrared Diode-Laser-Based Overtone Spectroscopy.
Applied Optics
|March 25, 2008
Summary
A portable laser sensor accurately detects ammonia (NH3) in bioreactors for space missions. This rugged device offers rapid, sensitive measurements, supporting water treatment technology development.
Area of Science:
- Analytical Chemistry
- Spectroscopy
- Environmental Monitoring
Background:
- Accurate trace gas detection is crucial for environmental monitoring and life support systems.
- Ammonia (NH3) is a key indicator in bioreactor processes and atmospheric studies.
- Existing detection methods may lack portability, ruggedness, or real-time capabilities.
Purpose of the Study:
- To develop and demonstrate a portable diode-laser-based sensor for sensitive NH3 detection.
- To evaluate the sensor's performance in a bioreactor environment for space applications.
- To assess the feasibility of simultaneous NH3 and CO2 measurements.
Main Methods:
- Utilized vibrational overtone absorption spectroscopy at 1.53 µm.
- Employed fiber-coupled optical elements for a rugged and easily aligned sensor design.
- Integrated on-line data acquisition and processing using a laptop PC with LabVIEW software (<30 s).
Main Results:
- Achieved a sensitivity of 0.7 parts per million (ppm) for NH3 detection (SNR=3) over a two-week period.
- Demonstrated the sensor's reliability and performance within a NASA bioreactor for water treatment.
- Confirmed the feasibility of simultaneous, real-time NH3 and CO2 concentration measurements.
Conclusions:
- The portable diode-laser sensor provides a robust and efficient solution for trace NH3 monitoring.
- The technology is suitable for applications in bioreactors, supporting long-duration space missions.
- The sensor platform shows potential for multi-gas analysis in environmental and life support systems.
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