HUMAN BREATH TRACE GAS CONTENT STUDY BY TUNABLE DIODE-LASER SPECTROSCOPY TECHNIQUE

Measurements of carbon monoxide, ammonia, methane and carbon dioxide c oncentrations by registration of high resolution absorption spectra ar e described. A description of the automated tunable diode laser (TDL) system developed for simultaneous CO and CO2 measure, and the TDL syst em developed for CH4 and NH3 measure is given. Calibration of concentr ation calculated on the base of a priori data on strength and broadeni ng coefficients of detected lines is described. A clarified correct ma nner of value definition of spontaneous fraction of TDL' radiation all ows an accuracy improvement of concentration measurement of several pe rcent. The same level of CO surplus content of about 400-800 ppb in no n-smoker's respiration was detected under different ambient conditions of CO content varied within one order of magnitude. A surplus content in human respiration of CH4 equal to similar to 3-8 ppm and NH3 equal to 100-250 ppb were detected. The accumulation of CH4 and NH3 by the human organism seems to be rather negligible for a short time exposure , e.g. like smoking. Data obtained on non-invasive CO/CO2 ratio detect ion in human breath shows that after 10-20 sec of breath holding time the organism's compensation reactions on acuity oxygen shortage for br eath holding appear. Prospects for the development and application of diode laser spectroscopy to trace gas analysis in medicine are also di scussed.