Laser sensors for trace gases in human breath

Abstract

Ethylene and ethane as biomarkers for lipid peroxidation in humans can be detected in the exhaled breath by means of very sensitive gas sensors based on high-resolution molecular spectroscopy. To this purpose, a laser photoacoustic spectroscopy sensor (PAS) for online ethylene monitoring and a tunable diode laser absorption spectroscopy sensor (TDLAS) for ethane detection were developed at ENEA Frascati Molecular Spectroscopy Laboratory. The sensors have been calibrated by certified mixtures. The main advantages of the breath analysis by spectroscopic technique are the high sensitivity and the absolutely non-invasive character. During an experimental study in cooperation with Umberto I Hospital (Radiology Institute) of Rome, we were able to detect very low concentrations (under 1 ppb) of trace ethylene content in the air exhaled by patients, following X-ray therapy; results are reported in this article.

Keywords:

• Medicine
• Laser spectroscopy sensors
• Breath analysis
• Lipid peroxidation