Methods for comparing the relative content of isotopes 12CO2 and 13CO2 in the sample gas mixture and DEVICE FOR COMPARISON OF RELATIVE isotopes 12CO2 and 13CO2 in the sample gas mixtures

摘要

FIELD: physics.;SUBSTANCE: invention can be used to compare isotopic abundance of CO₂ in samples of gas mixtures, as well as for measuring relative concentration of ¹²CO₂ and ¹³CO₂ isotopomers in expired air for biomedical diagnosis purposes. The method involves measuring resonance absorption of ¹²CO₂ and ¹³CO₂ molecules using a tunable diode laser whose optical frequency is periodically scanned in the analytical spectral range. Radiation which has passed through cuvettes with the analysed and reference mixtures is detected using photodetectors while recording the first and/or second transmission spectrum derivatives.;EFFECT: invention enables to analyse compared samples of gas mixtures simultaneously and synchronously with sufficient sensitivity as well as accuracy, selectivity, speed and information content of measurements.;2 cl, 3 dwg