| Title: | Proton transfer reaction time-of-flight mass spectrometric measurements of volatile compounds contained in peppermint oil capsules of relevance to real-time pharmacokinetic breath studies |
| Author(s): | Malaskova M; Henderson B; Chellayah PD; Ruzsanyi V; Mochalski P; Cristescu SM; Mayhew CA; |
| Address: | "Institute for Breath Research, Leopold-Franzens-Universitat Innsbruck, Rathausplatz 4, A-6850, Dornbirn, Austria" |
| ISSN/ISBN: | 1752-7163 (Electronic) 1752-7155 (Linking) |
| Abstract: | "With the growing interest in the use of breath volatiles in the health sciences, the lack of standardization for the sampling and analysis of exhaled breath is becoming a major issue leading to an absence of conformity, reproducibility and reliability in spectrometric measurements. Through the creation of a worldwide 'peppermint consortium', the International Association of Breath Research has set up a task force to deal with this problem. Pharmacokinetic studies are proposed, and a real-time analytical technique that is being used is proton transfer reaction-time-of-flight-mass spectrometry (PTR-ToF-MS). This paper presents details on how the volatile compounds contained in a peppermint oil capsule, and hence on breath, appear in a PTR-ToF-MS. To aid that study, the key volatiles in the headspace of peppermint oil were first identified using gas chromatography-mass spectrometry, notably: menthol, menthone, 1,8-cineole, menthofuran, limonene, alpha-pinene and beta-pinene. A PTR-ToF-MS analysis of these compounds has been undertaken, divorced from the complexity of the peppermint oil matrix using 'normal' and 'saturated' humidity drift-tube conditions, with the latter used to mimic breath samples, and over a range of reduced electric fields. There are no characteristic product ions that can distinguish monoterpenes and 1,8-cineole, and hence, without pre-separation, a combined washout for these volatiles can only be provided. By operating the drift tube above about 130 Td, there are characteristic product ions for menthone, menthofuran and menthol, namely m/z 155.14 (protonated menthone), m/z 151.11 (protonated menthofuran), m/z 139.15 (loss of H(2)O from protonated menthol) and m/z 83.09 (a fragment ion, C(6)H(11) (+), from menthol). These have been used to monitor, with a high specificity, the temporal profile of these three compounds in breath following the ingestion of a peppermint oil capsule. To aid in the analyses, the proton affinities and gas-phase basicities for the key volatiles investigated have been determined using density functional theory" |
| Keywords: | Breath Tests/*methods Capsules Density Functional Theory Electricity Exhalation Gas Chromatography-Mass Spectrometry/*methods Humans Ions Mentha piperita Plant Oils/*chemistry *Protons Reference Standards Reproducibility of Results Time Factors Volatile O; |
| Notes: | "MedlineMalaskova, Michaela Henderson, Ben Chellayah, Prema D Ruzsanyi, Veronika Mochalski, Pawel Cristescu, Simona M Mayhew, Chris A eng Research Support, Non-U.S. Gov't England 2019/06/05 J Breath Res. 2019 Jul 18; 13(4):046009. doi: 10.1088/1752-7163/ab26e2" |
