| Title: | Effects of elevated oxygen levels on VOC analysis by means of PTR-ToF-MS |
| Author(s): | Trefz P; Pugliese G; Brock B; Schubert JK; Miekisch W; |
| Address: | "Department of Anaesthesia and Intensive Care, University Medicine Rostock, Schillingallee 35, D-18057 Rostock, Germany" |
| ISSN/ISBN: | 1752-7163 (Electronic) 1752-7155 (Linking) |
| Abstract: | "Proton-transfer-reaction-time-of-flight-mass-spectrometry (PTR-ToF-MS) is a powerful tool for real-time monitoring of volatile organic compound (VOC) profiles in human breath. However, varying oxygen concentrations in the sample matrix may influence results from VOC analysis by PTR-ToF-MS. Elevated oxygen concentrations are likely to occur in clinical settings, but also when respiratory masks or breathing apparatus are used (e.g. in scuba diving, aviation, firefighting). Oxygen concentration may vary between subjects or within the course of a measurement or study and thus bias results. We systematically assessed the effect of high O(2) concentrations (up to 90%) in the sample matrix on the results of PTR-MS analysis for a pattern of VOCs including aromatics, aldehydes and ketones in dry and humid samples. In vivo experiments in healthy volunteers and mechanically ventilated animals were done to test the effect under real-life conditions. H(3)O(+) count significantly decreased by more than 40% when the amount of oxygen in the sample matrix was increased. Almost all investigated VOCs were significantly effected by varying oxygen concentrations and differences in signal intensities of more than 50% could be observed. The effect was generally more pronounced in dry samples but still significant under humid conditions. A linear dependency of sensitivity on the oxygen concentration in the sample matrix was observed for a number of VOCs (e.g. aldehydes) possibly enabling a factor based correction. VOC intensities were also influenced under in vivo conditions, e.g. ethanol decreased up to 71%. When PTR-MS analysis is carried out under oxygen supply, these issues need to be carefully considered" |
| Keywords: | "Adult Animals Breath Tests/methods Humans Mass Spectrometry/*methods Oxygen/*pharmacology *Protons Respiration, Artificial Swine Volatile Organic Compounds/*analysis Water;" |
| Notes: | "MedlineTrefz, Phillip Pugliese, Giovanni Brock, Beate Schubert, Jochen K Miekisch, Wolfram eng Research Support, Non-U.S. Gov't England 2019/06/12 J Breath Res. 2019 Jul 9; 13(4):046004. doi: 10.1088/1752-7163/ab28ec" |
