An adaptive absorption spectroscopy with adjustable moving window width for suppressing nonlinear effects in...

Area of Science:

• Analytical Chemistry
• Spectroscopy
• Environmental Monitoring

Background:

• Lambert-Beer law is fundamental to absorption spectroscopy but suffers from nonlinearity.
• Nonlinear effects in absorbance measurements limit accuracy in material analysis and chemical kinetics.
• Existing methods struggle with accurate concentration measurements across diverse environments.

Purpose of the Study:

• To introduce an adaptive absorption spectroscopy (A-AS) method to overcome nonlinearity.
• To develop a technique with adjustable parameters for suppressing nonlinear effects.
• To validate A-AS for accurate and stable concentration measurements.

Main Methods:

• Introduced the moving window concept to spectral nonlinearity.
• Developed A-AS with adjustable moving window parameters.
• Applied A-AS to differential optical absorption spectroscopy for SO2 detection, calculating and screening k-values to find optimal k_best for concentration inversion.

Main Results:

• A-AS effectively suppresses nonlinear effects in absorbance measurements.
• Demonstrated excellent performance in SO2 detection, with maximum error of 1.3% and standard deviation of 3.8.
• Achieved good linearity and stability across the entire concentration range, outperforming broad-band and narrow-band methods.

Conclusions:

• A-AS provides a universally adaptable solution for dynamic linear measurements.
• The method ensures high accuracy and stability in both high and low concentration environments.
• A-AS significantly enhances the reliability of absorption spectroscopy for various applications.