title: Real-time breath analysis with active capillary plasma ionization-ambient mass spectrometry.
abstract: On-line analysis of exhaled human breath is a growing area in analytical science, for applications such as fast and non-invasive medical diagnosis and monitoring. In this work, we present a novel approach based on ambient ionization of compounds in breath and subsequent real-time mass spectrometric analysis. We introduce a plasma ionization source for this purpose, which has no need for additional gases, is very small, and is easily interfaced with virtually any commercial atmospheric pressure ionization mass spectrometer (API-MS) without major modifications. If an API-MS instrument exists in a laboratory, the cost to implement this technology is only around [Formula: see text]500, far less than the investment for a specialized mass spectrometric system designed for volatile organic compounds (VOCs) analysis. In this proof-of-principle study we were able to measure mass spectra of exhaled human breath and found these to be comparable to spectra obtained with other electrospray-based methods. We detected over 100 VOCs, including relevant metabolites like fatty acids, with molecular weights extending up to 340 Da. In addition, we were able to monitor the time-dependent evolution of the peaks and show the enhancement of the metabolism after a meal. We conclude that this approach may complement current methods to analyze breath or other types of vapors, offering an affordable option to upgrade any pre-existing API-MS to a real-time breath analyzer.
authors.affiliation: Department of Chemistry and Applied Biosciences, ETH Zurich, Zurich, Switzerland.
authors.forename: Lukas
authors.initials: L
authors.lastname: Bregy
authors.forename: Pablo Martinez-Lozano
authors.initials: PM
authors.lastname: Sinues
authors.forename: Maryia M
authors.initials: MM
authors.lastname: Nudnova
authors.forename: Renato
authors.initials: R
authors.lastname: Zenobi
mesh_terms: D001944:Breath Tests / Q000295:instrumentation* / Q000379:methods*; D003199:Computer Systems; D045853:Exhalation; D005260:Female; D005740:Gases / Q000032:analysis / Q000737:chemistry; D006801:Humans; D008297:Male; D013058:Mass Spectrometry / Q000295:instrumentation* / Q000379:methods*; D058626:Plasma Gases / Q000737:chemistry*; D025341:Principal Component Analysis; D055549:Volatile Organic Compounds / Q000032:analysis / Q000737:chemistry
chemical_list: D005740:Gases; D058626:Plasma Gases; D055549:Volatile Organic Compounds