Online recording of ethane traces in human breath via infrared laser spectroscopy

Abstract

A method is described for rapidly measuring the ethane concentration in exhaled human breath. Ethane is considered a volatile marker for lipid peroxidation. The breath samples are analyzed in real time during single exhalations by means of infrared cavity leak-out spectroscopy. This is an ultrasensitive laser-based method for the analysis of trace gases on the sub-parts per billion level. We demonstrate that this technique is capable of online quantifying of ethane traces in exhaled human breath down to 500 parts per trillion with a time resolution of better than 800 ms. This study includes what we believe to be the first measured expirograms for trace fractions of ethane. The expirograms were recorded after a controlled inhalation exposure to 1 part per million of ethane. The normalized slope of the alveolar plateau was determined, which shows a linear increase over the first breathing cycles and ends in a mean value between 0.21 and 0.39 liter Ϫ1 . The washout process was observed for a time period of 30 min and was modelled by a threefold exponential decay function, with decay times ranging from 12 to 24, 341 to 481, and 370 to 1,770 s. Our analyzer provides a promising noninvasive tool for online monitoring of the oxidative stress status. alveolar slope; breath analysis; cavity leak-out spectroscopy; lipid peroxidation; oxidative stress; washout AMONG THE VARIOUS VOLATILE hydrocarbons found in breath, the alkanes ethane (C 2 H 6 ) and pentane (C 5 H 12 ) have been extensively studied since they were identified as end products of the oxidative degradation (lipid peroxidation) of polyunsaturated fatty acids. The process of lipid peroxidation has gained interest as one of the important features of free radical-induced damage in biology and medicine (29). During peroxidation of omega-3 and omega-6 fatty acids, ethane and pentane, respectively, are formed and excreted via the lungs and thus can be detected in exhaled breath. Because lipid peroxidation is considered as the major, probably the only endogenous source of pentane and ethane, these volatile compounds may serve as specific markers for oxidative damage (8,25).The first report of breath ethane as a marker of in vivo lipid peroxidation was published by Riely et al. in 1974 (24). During the past decade, several studies provided evidence that ethane and pentane in exhaled air are useful markers of in vivo lipid peroxidation under certain clinical conditions (1-4, 8, 19, 20, 26, 27). Because pentane is metabolized in the liver, ethane is considered as the more reliable marker (10).Despite the growing number of reports on breath ethane and pentane, the development of rapid and sensitive analysis techniques for measurements of these markers in exhaled breath still remains a challenge. Ethane and pentane fractional concentrations in expired air are in the parts per billion (ppb; 1:10 9 ) range, which is below the detection limit of most analytical methods.The technique usually applied for quantifying these hydrocarbons in exhaled breath is gas chromatography (...

Human exhaled air analytics: biomarkers of diseases

“…Laser spectrometry-based devices for the detection of particular compounds (e.g. ethane carbon monoxide, carbonyl sulfide or nitric oxide) can also be used to investigate exhaled breath on a breath-to-breath basis (von Basum et al, 2003(von Basum et al, , 2005Wysocki et al, 2004) and have the potential to become small in the future (e.g. down to the size of a cigarette box).…”

Technology Assessment and Roadmap for the Emergency Radiation Dose Assessment Program

“…The study by Mueller et al (1998) evaluated breath analysis of exhaled air by mechanically ventilated patients using microwave energy desorption coupled with gas chromatography-flame ionization detection-mass spectrometry. Infrared laser spectroscopy was used by Basum et al (2003) who were able to detect in near realtime 500 ppt ethane. Malandialdehyde is a well developed diagnostic for lipid oxidation but little is known of its utility as a marker of radiation exposure.…”

Gas sensing demonstration by using silica high-mesa waveguide with amplified cavity ring down spectroscopy technique

“…We focus on breath content as a disease marker, because the breath contains various diagnostic information [1,2,3,4], such as for digestive disease [2], lipid peroxidation [4], and lung disease, particularly asthma [2,3], with less stress to human beings. When downsizing such a breath-sensing system, however, a gas-cell becomes a major bottleneck since it consists of a long optical path length (approximately 1 meter long) for ppm-order disease-marker volatile gases in the breath [2,3,4]. For instance, the required length reaches 1 m over in case of detecting 10 ppm CH 4 (disease marker of the digestive disease [2]) in the breath.…”

“…When downsizing such a breath-sensing system, however, a gas-cell becomes a major bottleneck since it consists of a long optical path length (approximately 1 meter long) for ppm-order disease-marker volatile gases in the breath [2,3,4]. For instance, the required length reaches 1 m over in case of detecting 10 ppm CH 4 (disease marker of the digestive disease [2]) in the breath. In order to solve this problem, we have proposed a silica high-mesa waveguide [5] for the gas-cell (breath detection part).…”

“…Thus, we propose amplified CRDS for compensating the loss of optical waveguide. Moreover, health check will be possible by measuring concentration of CH 4 . Presently we plan to realize integrated device with having "high-mesa waveguide" and "coupler", which corresponds to "gas cavity" and "mirrors" in conventional CRDS gas cavity, as shown in Fig.…”