Real-time, subsecond, multicomponent breath analysis by Optical Parametric Oscillator based Off-Axis Integrated...

Area of Science:

• Analytical Chemistry
• Biomedical Engineering
• Spectroscopy

Background:

• Breath analysis offers a non-invasive approach for medical diagnostics.
• Laser-based absorption spectroscopy provides high sensitivity, selectivity, and temporal resolution for gas detection.

Purpose of the Study:

• To develop and demonstrate a rapid and sensitive trace gas detection system for exhaled breath analysis.
• To showcase the capability of a specific laser system coupled with Off-Axis Integrated Cavity Output Spectroscopy (OA-ICOS) for real-time breath analysis.

Main Methods:

• Utilized a fast-scanning continuous wave, singly-resonant Optical Parametric Oscillator (OPO) laser system (3-4 μm wavelength range, 40 MHz linewidth, >1 W output power, 100 THz/s scanning speed).
• Employed Off-Axis Integrated Cavity Output Spectroscopy (OA-ICOS) for trace gas detection.
• Performed real-time analysis of exhaled human breath during free exhalations.

Main Results:

• Achieved real-time, low parts-per-billion by volume (ppbv) detection of ethane in exhaled breath.
• Demonstrated simultaneous, real-time detection of multiple gases including ethane, methane, and water within 1 second over a 17 cm⁻¹ spectral range.
• Showcased real-time detection of acetone with a sub-second time resolution (0.4 s).

Conclusions:

• The developed laser-based OA-ICOS system enables rapid and sensitive real-time detection of multiple volatile organic compounds and other gases in human breath.
• This technology holds significant potential for non-invasive medical diagnostics through breath analysis.