Breath-Resolved Monitoring of Metabolic Trace Gases with Photothermal Spectroscopy

Breath analysis has long been a particular target of interest in the development of laser spectroscopic methods. The possibility of non-invasive sampling of biomarkers and physiological parameters for diagnostics is an attractive goal, and its sensitivity, specificity and fast response make laser spectroscopy a suitable technique to this end. This holds especially for the detection of light-molecule components with high physiological significance such as nitrous oxide (N20)[I] or ammonia (NH3)[2]. Thanks to their particular high sensitivity without the need for bulky long-path cells, photothermal methods are a frequent choice for breath gas analysis [3]–[5].