Bettina Streckenbach, Justinas Sakas, Nathan Perkins, Malcolm Kohler, Alexander Moeller and Renato Zenobi.

Applications for direct breath analysis by mass spectrometry (MS) are rapidly expanding. One of the more recent mass spectrometry-based approaches is secondary electrospray ionization coupled to high-resolution mass spectrometry (SESI-HRMS). Despite increasing usage, the SESI methodology still lacks standardization procedures for quality control and absolute quantification.

Cedric Wüthrich, Zhiyuan Fan, Guy Vergères, Fabian Wahl, Renato Zenobi and Stamatios Giannoukos.s

Quantification of metabolites present within exhaled breath is a major challenge for on-line breath analysis. It is also important for gauging the analytical performance, accuracy, reproducibility, reliability, and stability of the measuring technology. Short-chain fatty acids (SCFAs) are of high interest for nutrition and health.

Amanda Gisler, Kapil Dev Singh, Jiafa Zeng, Martin Osswald, Mo Awchi, Fabienne Decrue, Felix Schmidt, Noriane A. Sievi, Xing Chen, Jakob Usemann, Urs Frey, Malcolm Kohler, Xue Li, Pablo Sinues

Exhaled breath contains valuable information at the molecular level and offers promising potential for precision medicine. However, few breath tests transition to routine clinical practice, partly because of the missing validation in multicenter trials. Therefore, we developed and applied an interoperability framework for standardized multicenter data acquisition and processing for breath analysis with secondary electrospray ionization-high resolution mass spectrometry.

Ronja Weber, Jérôme Kaeslin, Sophia Moeller, Nathan Perkins, Srdjan Micic, and Alexander Moeller.

Environmental volatile organic compounds (VOCs) from the ambient air potentially influence on-line breath analysis measurements by secondary electrospray ionization high-resolution mass spectrometry (SESI-HRMS). The aim of this study was to investigate how inhaling through a VOC filter affects the detected breath profiles and whether it is feasible to integrate such filters into routine measurements..

T. Zivkovic Semren*, S. Majeed, M. Fatarova, C. Laszlo, C. Pak, S. Steiner, G. Vidal, A. Kuczaj, A. Mazurov, M. C. Peitsch, N. V. Ivanov, J. Hoeng, P. A. Guy

Inhalation as a route for administering drugs and dietary supplements has garnered significant attention over the last decade. We performed real-time analysis of aerosols using secondary electrospray ionization (SESI) technology interfaced with high-resolution mass spectrometry (HRMS)

R Weber, B Streckenbach, J Kaeslin, L Welti, D Inci, N Perkins, R Zenobi, S Micic, A Möller.
We hypothesized that the breath of children with allergic asthma contains a unique signature of disease specific metabolites. Using secondary electrospray ionization high-resolution mass spectrometry (SESI-HRMS), we aimed to identify relevant VOCs to assess underlying interconnections between biomarkers belonging to common metabolic pathways in the pathophysiology of asthma.

Felix Schmidt, Nora Nowak, Patrick Baumgartner, Thomas Gaisl, Stefan Malesevic, Bettina Streckenbach, Noriane A. Sievi, Esther I. Schwarz, Renato Zenobi, Steven A. Brown, and Malcolm Kohler.

The direct pathophysiological effects of obstructive sleep apnea (OSA) have been well described. However, the systemic and metabolic consequences of OSA are less well understood.

A. Gómez-Mejia, K. Arnold, J. Bär, K. Dev Singh, T. C. Scheier, S. D. Brugger, A. S. Zinkernagel, P. Sinues

Early detection of pathogenic bacteria is needed for rapid diagnostics allowing adequate and timely treatment of infections.

Ronja Weber, Nathan Perkins, Tobias Bruderer, Srdjan Micic and Alexander Moeller.

The early detection of inflammation and infection is important to prevent irreversible lung damage in cystic fibrosis. Novel and non-invasive monitoring tools would be of high benefit for the quality of life of patients.

F. Schmidt ; M. Osswald ; R. Zenobi ; M. Kohler

Monitoring of drug pharmacokinetics is used in personalized therapy, therapeutic drug monitoring (TDM), toxicology assessments, doping controls and clinical drug development. Drugs are predominantly measured in plasma, serum or urine. Monitoring of volatile organic compounds (VOCs) in breath has so far not received much attention, but nevertheless it has many advantages over conventional approaches

B. Streckenbach, M. Osswald, S. Malesevic, R. Zenobi, and M. Kohler

Chemical analysis of exhaled breath have suggested the existence of an OSA-specific metabolic signature. Here, we validated this diagnostic approach and the proposed marker compounds, as well as their potential to reliably diagnose OSA.

Jérôme Kaeslin, Cedric Wüthrich, Stamatios Giannoukos, and Renato Zenobi

Secondary electrospray ionization (SESI) is a soft ionization method, which is important to avoid interference from in-source fragments and to simplify compound annotation. In this work, it is shown that SESI is softer than electrospray ionization (ESI), and therefore, SESI indeed qualifies as a soft ionization technique. However…

A. Gómez-Mejia, K. Arnold, J. Bär, K. Dev Singh, T. C. Scheier, S. D. Brugger, A. S. Zinkernagel, P. Sinues

Early detection of pathogenic bacteria is needed for rapid diagnostics allowing adequate and timely treatment of infections.

C. Wüthrich, M.de Figueiredo, K. J. Burton-Pimentel, G. Vergères, F. Wahl, R. Zenobi and S. Giannoukos

For the first time, this study demonstrates the application of SESI-HRMS in the field of nutritional science using a standardized nutritional intervention, consisting of a high-energy shake. Tentative compounds include fatty acids, amino acids, and amino acid derivatives, some of them likely derived from nutrients by the gut microbiome, as well as organic acids from the Krebs cycle. Time-series clustering showed an overlap of observed kinetic trends with those reported previously in blood plasma.

Kim Arnold, Xing Chen, Hui Zhang, Kapil Dev Singh, Zhihong Yin, Yao Yao, Tiangang Luan, Pablo Sinues, and Xue Li

Secondary electrospray ionization-high resolution mass spectrometry allows monitoring in vivo 2H-incorporation of metabolites in a non-invasive and real-time setup and opens new opportunities to use 2H tracing to extend current metabolic studies, especially those with a focus on anaerobic glycolysis, lysine methylation and gut microbiome via monitoring of short-chain fatty acids.

Charles D.Smith, Ashley C.Fulton, Mark Romanczyk, Braden C. Giordano, Christopher J. Katilie, Lauryn E. DeGreeffe

Determination of fentanyl vapor signature enables the identification of target analytes for the indirect detection of the parent opioid without direct sample handling.

Hendrik G. Mengers, Christina Schier, Martin Zimmermann, Martin C. H. Gruhlke, Eric Block, Lars M. Blank*, Alan J. Slusarenko

Using SESI-Orbitrap MS, we measured gas phase concentrations of allicin evaporating from a pure solution. The SESI-Orbitrap MS was used to follow the known chemistry of alliin, isoallin and methiin conversion in garlic, onion and ramsons. Allicin and its metabolites were also measured in human breath after garlic consumption. These results demonstrate the utility of SESI-Orbitrap MS for analysis of sulfur-containing volatiles from plants and for capturing volatilomes of foodstuffs in general.

Hendrik G. Mengers, Martin Zimmermann & Lars M. Blank

We use secondary electrospray ionisation high-resolution Orbitrap mass spectrometry (SESI-Orbitrap MS) to monitor the complete yeast volatilome every 2.3 s. Over 200 metabolites were identified during growth in shake flasks and bioreactor cultivations, all with their unique intensity profile. Special attention was paid to ethanol as biotech largest product and to acetaldehyde as an example of a low-abundance but highly volatile metabolite. Volatilome shifts are visible, e.g. after glucose depletion, fatty acids are converted to ethyl esters in a detoxification mechanism after stopped fatty acid biosynthesis. This work showcases the SESI-Orbitrap MS system for tracking microbial physiology without the need for sampling and for time-resolved discoveries during metabolic transitions.

Wetter Slack, Emma (ETH Zurich)

Dataset used in Non-invasive monitoring of microbiota and host metabolism using secondary electrospray ionization.

Jiayi Lan, Giorgia Greter, Bettina Streckenbach, Markus Arnoldini, Renato Zenobi & Emma Slack

We demonstrate that secondary electrospray ionization mass spectrometry can be used to non-invasively monitor metabolic activity of the intestinal microbiome of a live, awake mouse. This was achieved via analysis of the headspace volatile and semi-volatile metabolome of individual gut microbiota bacterial species growing in pure culture, as well as from live gnotobiotic mice specifically colonized with these microbes. The microbial origin of these compounds was confirmed by feeding of heavy-isotope labeled microbiota-accessible sugars. This reveals that the microbiota is a major contributor to the released metabolites of a whole live mouse, and that it is possible to capture the catabolism of sugars and cross-feeding within the gut microbiota of a living animal using volatile/semi-volatile metabolite monitoring.