Narrowband Laser Gas Analyzer for Real-Time Respiratory Trace Detection
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Solution Overview
Problem
Current respiratory gas analysis methods lack the necessary sensitivity, selectivity, and real-time capabilities for quantitative detection of trace gases in the ppm to ppb range, limiting their application in clinical diagnostics and therapy monitoring due to issues with stability, interference from other gases, and laborious sample collection processes.
Innovation Solution
A measurement device utilizing a narrow band emitting laser with a line width smaller than the absorption line of the sample gas, featuring periodic frequency variation and time-resolved detection, enabling single absorption measurements within 10^-5 seconds, and capable of detecting spectral ranges with high point density, thus achieving high sensitivity and accuracy for real-time analysis of respiratory gases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If highly sensitive detection methods like mass spectroscopy or FTIR-spectroscopy in multipass sample cells are used, then detection sensitivity is improved, but device complexity and suitability for clinical daily routine deteriorate
Solution Approach 1:
The patent extracts only the essential measurement function from complex multipass cells and mass spectrometers by using a simple single-pass measurement chamber combined with a tunable diode laser. This eliminates unnecessary complexity while maintaining high detection sensitivity through selective wavelength tuning at absorption lines.
Solution Approach 2:
The patent changes the optical parameter by using a tunable diode laser that can be adjusted to specific wavelengths corresponding to absorption lines of target gases. This allows selective detection with high sensitivity without requiring complex multipass optical paths or mass spectrometric analysis.
2Measurement precision
If NDIRS method is used, then detection sensitivity is improved, but measurement accuracy deteriorates due to interference from other gases like oxygen
Solution Approach 1:
The patent applies local quality by tuning the laser wavelength to specifically match the absorption line of the target gas. This selective wavelength targeting allows differentiation between different gases based on their unique absorption spectra, eliminating interference from other gases like oxygen that do not absorb at the selected wavelength.
Solution Approach 2:
The patent changes the spectral parameter by using a tunable laser that can be adjusted to specific absorption wavelengths. This enables selective detection of target gases while ignoring interfering gases, thereby maintaining both high sensitivity and accurate measurements free from cross-interference.
3Device complexity
If BreathID method with CO2 pressure lamp is used, then device simplicity is improved, but measurement sensitivity and speed deteriorate due to line width fluctuations and low light intensities
Solution Approach 1:
The patent replaces the broadband CO2 pressure lamp with a tunable diode laser that emits narrow-line spectral radiation. This substitution maintains device simplicity while dramatically improving sensitivity through selective wavelength tuning and narrow line width, enabling detection at absorption line peaks where sensitivity is maximized.
4Productivity
If real-time measurement is implemented, then productivity is improved, but measurement accuracy deteriorates due to fluctuations in respiratory gas composition
Solution Approach 1:
The patent implements periodic scanning of the laser wavelength across the absorption line. By continuously tuning the laser frequency and measuring absorption at multiple points, the system can track rapid fluctuations in gas composition while maintaining accuracy through real-time spectral analysis and integration of multiple measurements.
Solution Approach 2:
The patent uses a dynamically tunable laser that can rapidly scan across absorption lines. This dynamic wavelength adjustment allows the system to adapt to changing respiratory gas composition in real-time, maintaining measurement accuracy by continuously tracking absorption features despite fluctuations in concentration and environmental conditions.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The device allows for precise, real-time detection of trace gases and isotopic ratios in respiratory gases, enabling accurate metabolic parameter determination and quantitative analysis of CO2 concentrations, even at fluctuating levels, with minimal respiratory resistance and no need for external gas transport, facilitating its integration into clinical daily routine.
Implementation Method 1
Measurement device for analyzing a sample gas by infrared absorption spectroscopy
Implementation Method 2
detection device is designed and arranged to detect light emitted from the laser and radiated through the measurement chamber in a time-resolved manner such that light absorption can be detected frequency-resolved
Data Source
AI summary
A measurement device and a method for analyzing a sample gas by infrared absorption spectroscopy are described. The measurement device comprises a narrowband laser having a line width of less than 0.2 cm−1 and being smaller than a width of an infrared absorption line to be measured of a sample gas. The measurement device is suited and can be arranged to measure the respiratory gas of a human or animal as sample gas, wherein the respiratory gas exchanges in the measurement chamber only by the respiration of the human or animal, and the respiratory resistance of the measurement device is less than 60 mbar.