Diagnostic method for high sensitivity detection of component concentrations in human gas emissions

摘要

A method for detecting component concentrations in human gas emissions such as breath and gas emitted from skin. A gas sample containing a specified component is collected into a gas cell using a pump and a series of valves to draw the gas sample into the cell and control the gas pressure within the cell. A tunable optical radiation beam is passed through the gas cell and the amount of energy absorbed by the specified component may be measured indirectly by taking the difference between the incident and emerging beam energy or directly by optoacoustic methods. Concentrations of the specified component as small as 0.1 ppB may be determined. Additionally, the tunable optical radiation beam may be multiplexed for use with a plurality of systems utilizing the beam for medical purposes.

主权项

1. A diagnostic method for high sensitivity detection of component concentrations in human gas emissions comprising:
(a) collecting a gas sample in a gas cell, wherein the gas sample may contain a specified component being associated with a plurality of fundamental absorption peak frequencies; (b) passing a tunable optical radiation beam through the gas cell (1) when the gas cell contains a reference sample having a known concentration of the specified component and (2) when the gas cell contains the gas sample, wherein the frequency of the tunable optical radiation beam comprises a modulation frequency superimposed on a base frequency, and the base frequency is swept repeatedly through a series of frequencies such that the series of frequencies comprises at least one of the fundamental absorption peak frequencies; (c) measuring, after the tunable optical beam passes through the gas cell, as first signal outputs an amplitude of the tunable optical radiation beam at the modulation frequency, and as second signal outputs a power of the tunable optical radiation beam; and (d) determining, by electronics, a concentration of the specified component in the gas sample using the first signal outputs and the second signal outputs obtained from the reference sample and the gas sample.