Method and apparatus for determining gas concentration
First Claim
1. A method for measuring the concentration of a marker gas in a gas mixture comprising steps of;
- obtaining a gas mixture sample initially including said marker gas and a calibration gas having an independently known concentration and inherently present in said gas mixture for a gas mixture sampling interval;
providing a spectrometer including a spectrometer light source, a spectrometer gas sample cell, a spectrometer detector and a spectrometer computer;
placing said gas mixture sample in said spectrometer gas sample cell;
illuminating said gas mixture sample with said spectrometer light source;
detecting a transmitted light beam which has passed through said gas mixture sample with said spectrometer detector to produce a detector electronic signal sequence;
transmitting said detector electronic signal sequence to said spectrometer computer wherein said computer includes an executable program;
acquiring said detector electronic signal sequence using said spectrometer computer for a signal acquisition interval to obtain a gas mixture spectrum;
storing said gas mixture spectrum;
analyzing said gas mixture spectrum using said spectrometer computer said step of analyzing further including steps of;
identifying a marker gas absorption feature and a calibration gas absorption feature, determining a marker gas absorption feature intensity and a calibration gas absorption feature intensity, storing said marker gas absorption feature intensity and storing said calibration gas absorption feature intensity as a function of time over said gas mixture sampling interval;
repeating said steps of acquiring and analyzing for multiple signal acquisition intervals to identify a single signal acquisition interval wherein a known concentration calibration gas absorption feature which corresponds to an independently known calibration gas concentration and a simultaneous marker gas absorption feature occur;
calculating a ratio of said simultaneous marker gas absorption feature intensity to said known concentration calibration gas absorption feature intensity and multiplying said ratio by a proportionality constant to determine concentration of said marker gas.
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Accused Products
Abstract
A method and an apparatus for measuring the concentration of a specific gas component of a gas mixture including another gas whose concentration is independently known using light absorption spectroscopy are provided. A method and an apparatus for assessing human airway inflammation by measuring the concentration of exhaled NO and CO2 present in orally exhaled breath using light absorption spectroscopy are also provided. NO concentration is determined at the time during breath sampling corresponding to a known exhaled CO2 concentration. Methods and apparatus are further provided for measuring NO concentration in orally exhaled human breath that analyze breath emanating from the lower airways and lungs, while excluding breath from the nasal cavity. They include steps and apparatus for discarding initially exhaled breath, flowing breath through an analysis chamber using a vacuum pump and flowing breath through an analysis chamber using a vacuum pump at an initial flow rate and later at a flow rate higher than the initial flow rate.
52 Citations
70 Claims
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1. A method for measuring the concentration of a marker gas in a gas mixture comprising steps of;
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obtaining a gas mixture sample initially including said marker gas and a calibration gas having an independently known concentration and inherently present in said gas mixture for a gas mixture sampling interval;
providing a spectrometer including a spectrometer light source, a spectrometer gas sample cell, a spectrometer detector and a spectrometer computer;
placing said gas mixture sample in said spectrometer gas sample cell;
illuminating said gas mixture sample with said spectrometer light source;
detecting a transmitted light beam which has passed through said gas mixture sample with said spectrometer detector to produce a detector electronic signal sequence;
transmitting said detector electronic signal sequence to said spectrometer computer wherein said computer includes an executable program;
acquiring said detector electronic signal sequence using said spectrometer computer for a signal acquisition interval to obtain a gas mixture spectrum;
storing said gas mixture spectrum;
analyzing said gas mixture spectrum using said spectrometer computer said step of analyzing further including steps of;
identifying a marker gas absorption feature and a calibration gas absorption feature, determining a marker gas absorption feature intensity and a calibration gas absorption feature intensity, storing said marker gas absorption feature intensity and storing said calibration gas absorption feature intensity as a function of time over said gas mixture sampling interval;
repeating said steps of acquiring and analyzing for multiple signal acquisition intervals to identify a single signal acquisition interval wherein a known concentration calibration gas absorption feature which corresponds to an independently known calibration gas concentration and a simultaneous marker gas absorption feature occur;
calculating a ratio of said simultaneous marker gas absorption feature intensity to said known concentration calibration gas absorption feature intensity and multiplying said ratio by a proportionality constant to determine concentration of said marker gas. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A method for assessing human airway inflammation comprising steps of;
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collecting an orally exhaled human breath sample wherein said orally exhaled human breath sample further includes exhaled NO and exhaled CO2 for an exhalation interval;
providing a spectrometer including a spectrometer light source, a spectrometer gas sample cell, a spectrometer detector and a spectrometer computer;
placing said orally exhaled human breath sample in said spectrometer gas sample cell;
illuminating said orally exhaled human breath sample with a spectrometer light source;
detecting a transmitted light beam which has passed through said orally exhaled human breath sample with said spectrometer detector to produce a detector electronic signal sequence;
transmitting said detector electronic signal sequence to said spectrometer computer wherein said computer includes an executable program;
acquiring said detector electronic signal sequence using said spectrometer computer for a signal acquisition interval to obtain a human breath sample spectrum;
analyzing said human breath sample spectrum using said spectrometer computer, said step of analyzing further including steps of;
identifying an exhaled NO absorption feature and an exhaled CO2 absorption feature, determining an exhaled NO absorption feature intensity and an exhaled CO2 absorption feature intensity, storing said exhaled NO absorption feature intensity and said exhaled CO2 absorption feature intensity as a function of time;
repeating said acquiring and analyzing steps for multiple signal acquisition intervals to identify a single signal acquisition interval wherein a known concentration CO2 gas absorption feature which corresponds to an independently known CO2 gas concentration and a simultaneous NO absorption feature occur;
calculating a ratio of said simultaneous NO absorption feature intensity to said known concentration CO2 gas absorption feature intensity and multiplying said ratio by a proportionality constant to obtain concentration of said exhaled NO thereby providing an assessment of human airway inflammation. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27)
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28. An apparatus for measuring the concentration of a marker gas in a gas mixture sample initially including said marker gas and a calibration gas having an independently known concentration and inherently present in said gas mixture comprising;
a spectrometer light source for illuminating said gas mixture sample, a spectrometer gas sample cell including said gas mixture sample, a spectrometer detector for detecting light transmitted through said gas mixture sample so that a detector signal sequence is generated, and a spectrometer computer wherein said spectrometer computer further includes an executable program for repeatedly acquiring and analyzing said detector electronic signal sequence for multiple signal acquisition intervals to obtain gas mixture spectra, storing said gas mixture spectra, analyzing said gas mixture spectra by identifying a marker gas absorption feature and a calibration gas absorption feature, determining a marker gas absorption feature intensity and a calibration gas feature intensity, calculating marker gas absorption feature intensity and calibration gas absorption feature intensity as a function of time to identify a single signal acquisition interval wherein a known concentration calibration gas absorption feature which corresponds to an independently known calibration gas concentration and a simultaneous marker gas absorption feature occur;
calculating a ratio of said simultaneous marker gas absorption feature intensity to said known concentration calibration gas absorption feature intensity and multiplying said ratio by a proportionality constant to determine concentration of said marker gas.- View Dependent Claims (29, 30, 31, 32, 33, 34, 35, 36, 37)
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38. An apparatus for assessing human airway inflammation comprising;
a spectrometer gas sample cell including an orally exhaled human breath sample containing exhaled NO and exhaled CO2, a spectrometer light source for illuminating said orally exhaled human breath sample, a spectrometer detector for detecting light transmitted through said orally exhaled human breath sample so that a detector signal sequence is generated, and a spectrometer computer wherein said spectrometer computer further includes an executable program for repeatedly acquiring and analyzing said detector electronic signal sequence for multiple signal acquisition intervals to obtain human breath sample spectra, storing said human breath sample spectra, analyzing said human breath sample spectra by identifying an exhaled NO absorption feature and an exhaled CO2 absorption feature, determining an exhaled NO absorption feature intensity and an exhaled CO2 absorption feature intensity, storing said exhaled NO absorption feature intensity and said exhaled CO2 absorption feature intensity as a function of time, repeating said steps of acquiring and analyzing for multiple signal acquisition intervals to identify a single signal acquisition interval wherein a known concentration CO2 gas absorption feature which corresponds to an independently known CO2 gas concentration and a simultaneous NO absorption feature occur;
calculating a ratio of said simultaneous NO absorption feature intensity to said known concentration CO2 gas absorption feature intensity and multiplying said ratio by a proportionality constant to obtain concentration of said exhaled NO thereby providing an assessment of human airway inflammation.- View Dependent Claims (39, 40, 41, 42, 43, 44, 45, 46, 47)
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48. A method for measuring NO concentration in orally exhaled human breath comprising steps of;
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having a human subject normally orally exhale a single breath, including initial orally exhaled human breath and remaining orally exhaled human breath into a mouthpiece;
collecting said initially exhaled human breath in a discard container;
discarding said initially orally exhaled human breath;
flowing said remaining orally exhaled human breath from said mouthpiece to an NO analysis system through a tube connected to a vacuum pump and to said NO analysis system;
analyzing said remaining orally exhaled human breath to obtain said NO concentration. - View Dependent Claims (49, 50, 51, 52)
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53. An apparatus for measuring NO concentration in orally exhaled human breath comprising;
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a mouthpiece for accepting orally exhaled human breath, including initially exhaled human breath and remaining exhaled human breath from a human subject;
a discard container connected to said mouthpiece for collecting said initially exhaled human breath;
a flow tube connected to said discard container and said mouthpiece and to a vacuum pump for delivering said remaining orally exhaled human breath to an NO analysis system for obtaining said NO concentration. - View Dependent Claims (54, 55, 56)
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57. A method for measuring NO concentration in orally exhaled human breath comprising steps of;
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having a human subject normally orally exhale a single breath into a mouthpiece;
flowing said single breath to a light absorption spectrometer system through a tube connected to a vacuum pump and to said light absorption spectrometer system;
analyzing said single breath with said light absorption spectrometer system to obtain said NO concentration. - View Dependent Claims (58, 59, 60)
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61. An apparatus for measuring NO concentration in orally exhaled human breath comprising;
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a mouthpiece for accepting orally exhaled human breath from a human subject;
a flow tube connected to said mouthpiece, to a vacuum pump and to a light absorption spectrometer system for delivering said orally exhaled human breath to said NO analysis system for obtaining said NO concentration. - View Dependent Claims (62)
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63. A method for measuring NO concentration in orally exhaled human breath comprising steps of;
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having a human subject normally orally exhale a single breath into a mouthpiece;
flowing said single breath from said mouthpiece to an NO analysis system through a tube connected to a vacuum pump and to said NO analysis system first at a first flow rate and later at a second flow rate, wherein said first flow rate is greater than said second flow rate;
analyzing said single breath with said NO analysis system to obtain said NO concentration. - View Dependent Claims (64, 65, 66, 67)
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68. An apparatus for measuring NO concentration in orally exhaled human breath comprising;
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a mouthpiece for accepting a single orally exhaled human breath from a human subject;
a flow tube connected to said mouthpiece, to a vacuum pump and to an NO analysis system and including a flow rate controller for sequentially generating a first flow rate and a second flow rate wherein said second flow rate is less than said first flow for delivering said single orally exhaled breath to said NO analysis system for obtaining said NO concentration. - View Dependent Claims (69, 70)
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Specification