Open AccessLaser-based absorption spectroscopy as a technique for rapid in-line analysis of respired gas concentrations of O2 and CO2
Author(s) -
Beth Cummings,
Michelle Hamilton,
Luca Ciaffoni,
Timothy R. Pragnell,
R. Peverall,
Grant A. D. Ritchie,
Gus Hancock,
Peter A. Robbins
Publication year - 2011
Publication title -
journal of applied physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.253
H-Index - 229
eISSN - 8750-7587
pISSN - 1522-1601
DOI - 10.1152/japplphysiol.00119.2011
Subject(s) - carbon dioxide , spectroscopy , absorption spectroscopy , tunable diode laser absorption spectroscopy , absorption (acoustics) , analytical chemistry (journal) , oxygen , detection limit , chemistry , gas analyzer , laser , gas analysis , wavelength , materials science , optics , tunable laser , optoelectronics , chromatography , physics , environmental chemistry , organic chemistry , quantum mechanics
The use of sidestream analyzers for respired gas analysis is almost universal. However, they are not ideal for measurements of respiratory gas exchange because the analyses are both temporally dissociated from measurements of respiratory flow and also not generally conducted under the same physical conditions. This study explores the possibility of constructing an all optical, fast response, in-line breath analyzer for oxygen and carbon dioxide. Using direct absorption spectroscopy with a diode laser operating at a wavelength near 2 μm, measurements of expired carbon dioxide concentrations were obtained with an absolute limit of detection of 0.04% at a time resolution of 10 ms. Simultaneously, cavity enhanced absorption spectroscopy at a wavelength near 760 nm was employed to obtain measurements of expired oxygen concentrations with an absolute limit of detection of 0.26% at a time resolution of 10 ms. We conclude that laser-based absorption spectroscopy is a promising technology for in-line analysis of respired carbon dioxide and oxygen concentrations.