Method for demodulating the overlapping absorption spectra of CO and CH4
Optics Express
|December 16, 2022
Summary
Accurate gas concentration measurement is challenging due to overlapping spectral lines. The Partial Least Squares (PLS) algorithm effectively measures CO concentration in mixed gases, even with significant spectral interference.
Area of Science:
- Analytical Chemistry
- Spectroscopy
- Chemical Sensing
Background:
- Laser absorption spectroscopy is crucial for gas concentration measurement.
- Spectral line broadening and overlap in mixed gases complicate accurate analysis.
- Interference from adjacent spectral lines hinders precise concentration calculations.
Purpose of the Study:
- To analyze the causes of spectral line overlap hindrance in gas mixture analysis.
- To evaluate the effectiveness of the Partial Least Squares (PLS) algorithm in overcoming spectral interference.
- To determine CO concentrations in a CO and CH4 gas mixture with high accuracy.
Main Methods:
- Analysis of spectral line broadening and overlap mechanisms.
- Application of the Partial Least Squares (PLS) algorithm.
- Experimental measurement of CO concentration in a CO/CH4 gas mixture.
Main Results:
- The study identified spectral line overlap as a significant hindrance to accurate gas concentration measurement.
- The PLS algorithm demonstrated robust performance in analyzing mixed gases.
- Relative error for CO concentration measurement remained below 10% even with a CH4/CO volume ratio of 100.
Conclusions:
- The Partial Least Squares (PLS) algorithm is a highly effective method for determining gas concentrations in mixtures.
- PLS successfully mitigates errors caused by significant spectral line broadening and interference.
- Accurate quantitative analysis of gas mixtures is achievable despite complex spectral overlaps.
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