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Wüthrich C, Käser T, Zenobi R, Giannoukos S. Internal Standard Addition System for Online Breath Analysis. Anal Chem 2024; 96:10871-10876. [PMID: 38937865 PMCID: PMC11238155 DOI: 10.1021/acs.analchem.4c01924] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2024] [Revised: 06/18/2024] [Accepted: 06/18/2024] [Indexed: 06/29/2024]
Abstract
Breath analysis with secondary electrospray ionization (SESI) coupled to mass spectrometry (MS) is a sensitive method for breath metabolomics. To enable quantitative assessments using SESI-MS, a system was developed to introduce controlled amounts of gases into breath samples and carry out standard addition experiments. The system combines gas standard generation through controlled evaporation, humidification, breath dilution, and standard injection with the help of mass-flow controllers. The system can also dilute breath, which affects the signal of the detected components. This response can be used to filter out contaminating compounds in an untargeted metabolomics workflow. The system's quantitative capabilities have been shown through standard addition of pyridine and butyric acid into breath in real time. This system can improve the quality and robustness of breath data.
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Affiliation(s)
- Cedric Wüthrich
- Department
of Chemistry and Applied Biosciences, ETHZ, Zurich, CH 8093, Switzerland
| | - Timon Käser
- Department
of Chemistry and Applied Biosciences, ETHZ, Zurich, CH 8093, Switzerland
| | - Renato Zenobi
- Department
of Chemistry and Applied Biosciences, ETHZ, Zurich, CH 8093, Switzerland
| | - Stamatios Giannoukos
- Department
of Chemistry and Applied Biosciences, ETHZ, Zurich, CH 8093, Switzerland
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2
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Wüthrich C, Zenobi R, Giannoukos S. Alternative electrolyte solutions for untargeted breath metabolomics using secondary-electrospray ionization high-resolution mass spectrometry. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2024; 38:e9714. [PMID: 38389333 DOI: 10.1002/rcm.9714] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2023] [Revised: 01/15/2024] [Accepted: 01/16/2024] [Indexed: 02/24/2024]
Abstract
RATIONALE Secondary-electrospray ionization (SESI) coupled with high-resolution mass spectrometry is a powerful tool for the discovery of biomarkers in exhaled breath. A primary electrospray consisting of aqueous formic acid (FA) is currently used to charge the volatile organic compounds in breath. To investigate whether alternate electrospray compositions could enable different metabolite coverage and sensitivities, the electrospray dopants NaI and AgNO3 were tested. METHODS In a proof-of-principle manner, the exhaled breath of one subject was analyzed repeatedly with different electrospray solutions and with the help of a spectral stitching technique. Capillary diameter and position were optimized to achieve proper detection of exhaled breath. The detected features were then compared using formula annotation. Using an evaporation-based gas standard system, the signal response of the different solutions was probed. RESULTS Principal component analysis revealed a substantial difference in features detected with AgNO3 . With silver, more sulfur-containing features and more unsaturated hydrocarbon compounds were detected. Furthermore, more primary amines were potentially ionized, as indicated by van Krewelen diagrams. In total, twice as many features were unique to AgNO3 than for other electrospray dopants. Using gas standards at known concentrations, the high sensitivity of FA as a dopant was demonstrated but also indicated alternate sensitivities of the other electrospray solutions. CONCLUSIONS This work demonstrated the potential of AgNO3 as a complementary dopant for further biomarker discovery in SESI-based breath analysis.
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Affiliation(s)
- Cedric Wüthrich
- Department of Chemistry and Applied Biosciences, ETHZ, Zurich, Switzerland
| | - Renato Zenobi
- Department of Chemistry and Applied Biosciences, ETHZ, Zurich, Switzerland
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Żuchowska K, Filipiak W. Modern approaches for detection of volatile organic compounds in metabolic studies focusing on pathogenic bacteria: Current state of the art. J Pharm Anal 2024; 14:100898. [PMID: 38634063 PMCID: PMC11022102 DOI: 10.1016/j.jpha.2023.11.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Revised: 10/03/2023] [Accepted: 11/15/2023] [Indexed: 04/19/2024] Open
Abstract
Pathogenic microorganisms produce numerous metabolites, including volatile organic compounds (VOCs). Monitoring these metabolites in biological matrices (e.g., urine, blood, or breath) can reveal the presence of specific microorganisms, enabling the early diagnosis of infections and the timely implementation of targeted therapy. However, complex matrices only contain trace levels of VOCs, and their constituent components can hinder determination of these compounds. Therefore, modern analytical techniques enabling the non-invasive identification and precise quantification of microbial VOCs are needed. In this paper, we discuss bacterial VOC analysis under in vitro conditions, in animal models and disease diagnosis in humans, including techniques for offline and online analysis in clinical settings. We also consider the advantages and limitations of novel microextraction techniques used to prepare biological samples for VOC analysis, in addition to reviewing current clinical studies on bacterial volatilomes that address inter-species interactions, the kinetics of VOC metabolism, and species- and drug-resistance specificity.
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Affiliation(s)
- Karolina Żuchowska
- Department of Pharmacodynamics and Molecular Pharmacology, Faculty of Pharmacy, Collegium Medicum in Bydgoszcz, Nicolaus Copernicus University in Torun, 85-089 Bydgoszcz, Poland
| | - Wojciech Filipiak
- Department of Pharmacodynamics and Molecular Pharmacology, Faculty of Pharmacy, Collegium Medicum in Bydgoszcz, Nicolaus Copernicus University in Torun, 85-089 Bydgoszcz, Poland
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Sola-Martínez RA, Zeng J, Awchi M, Gisler A, Arnold K, Singh KD, Frey U, Díaz MC, de Diego Puente T, Sinues P. Preservation of exhaled breath samples for analysis by off-line SESI-HRMS: proof-of-concept study. J Breath Res 2023; 18:011002. [PMID: 38029449 DOI: 10.1088/1752-7163/ad10e1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2023] [Accepted: 11/29/2023] [Indexed: 12/01/2023]
Abstract
Secondary electrospray ionization-high resolution mass spectrometry (SESI-HRMS) is an established technique in the field of breath analysis characterized by its short analysis time, as well as high levels of sensitivity and selectivity. Traditionally, SESI-HRMS has been used for real-time breath analysis, which requires subjects to be at the location of the analytical platform. Therefore, it limits the possibilities for an introduction of this methodology in day-to-day clinical practice. However, recent methodological developments have shown feasibility on the remote sampling of exhaled breath in Nalophan® bags prior to measurement using SESI-HRMS. To further explore the range of applications of this method, we conducted a proof-of-concept study to assess the impact of the storage time of exhaled breath in Nalophan® bags at different temperatures (room temperature and dry ice) on the relative intensities of the compounds. In addition, we performed a detailed study of the storage effect of 27 aldehydes related to oxidative stress. After 2 h of storage, the mean of intensity of allm/zsignals relative to the samples analyzed without prior storage remained above 80% at both room temperature and dry ice. For the 27 aldehydes, the mean relative intensity losses were lower than 20% at 24 h of storage, remaining practically stable since the first hour of storage following sample collection. Furthermore, the mean relative intensity of most aldehydes in samples stored at room temperature was higher than those stored in dry ice, which could be related to water vapor condensation issues. These findings indicate that the exhaled breath samples could be preserved for hours with a low percentage of mean relative intensity loss, thereby allowing more flexibility in the logistics of off-line SESI-HRMS studies.
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Affiliation(s)
- Rosa A Sola-Martínez
- Department of Biochemistry and Molecular Biology B and Immunology, University of Murcia, Murcia, Spain
| | - Jiafa Zeng
- University of Basel Children's Hospital (UKBB), Basel, Switzerland
- Department of Biomedical Engineering, University of Basel, Allschwil, Switzerland
| | - Mo Awchi
- University of Basel Children's Hospital (UKBB), Basel, Switzerland
- Department of Biomedical Engineering, University of Basel, Allschwil, Switzerland
| | - Amanda Gisler
- University of Basel Children's Hospital (UKBB), Basel, Switzerland
| | - Kim Arnold
- University of Basel Children's Hospital (UKBB), Basel, Switzerland
- Department of Biomedical Engineering, University of Basel, Allschwil, Switzerland
| | - Kapil Dev Singh
- University of Basel Children's Hospital (UKBB), Basel, Switzerland
- Department of Biomedical Engineering, University of Basel, Allschwil, Switzerland
| | - Urs Frey
- University of Basel Children's Hospital (UKBB), Basel, Switzerland
- Pediatric Respiratory Medicine, Department of Pediatrics, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
- Department of Biomedical Engineering, University of Basel, Allschwil, Switzerland
| | - Manuel Cánovas Díaz
- Department of Biochemistry and Molecular Biology B and Immunology, University of Murcia, Murcia, Spain
| | - Teresa de Diego Puente
- Department of Biochemistry and Molecular Biology B and Immunology, University of Murcia, Murcia, Spain
| | - Pablo Sinues
- University of Basel Children's Hospital (UKBB), Basel, Switzerland
- Department of Biomedical Engineering, University of Basel, Allschwil, Switzerland
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Omezzine Gnioua M, Spesyvyi A, Španěl P. Gas phase H +, H 3O + and NH 4+ affinities of oxygen-bearing volatile organic compounds; DFT calculations for soft chemical ionisation mass spectrometry. Phys Chem Chem Phys 2023; 25:30343-30348. [PMID: 37909271 DOI: 10.1039/d3cp03604a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2023]
Abstract
Quantum chemistry calculations were performed using the density functional theory, DFT, to understand the structures and energetics of organic ions relevant to gas phase ion chemistry in soft chemical ionisation mass spectrometry analytical methods. Geometries of a range of neutral volatile organic compound molecules and ions resulting from protonation, the addition of H3O+ and the addition of NH4+ were optimised using the B3LYP hybrid DFT method. Then, the total energies and the normal mode vibrational frequencies were determined, and the total enthalpies of the neutral molecules and ions were calculated for the standard temperature and pressure. The calculations were performed for several feasible structures of each of the ions. The proton affinities of several benchmark molecules agree with the accepted values within ±4 kJ mol-1, indicating that B3LYP/6-311++G(d,p) provides chemical accuracy for oxygen-containing volatile organic compounds. It was also found that the binding energies of H3O+ and NH4+ to molecules correlate with their proton affinities. The results contribute to the understanding of ligand switching ion-molecule reactions important for secondary electrospray ionisation, SESI, and selected ion flow tube, SIFT, mass spectrometries.
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Affiliation(s)
- Maroua Omezzine Gnioua
- J. Heyrovský Institute of Physical Chemistry of the Czech Academy of Sciences, Dolejškova 2155/3, 18223 Prague 8, Czech Republic.
- Faculty of Mathematics and Physics, Charles University, V Holešovičkách 747/2, 18000 Prague 8, Czech Republic
| | - Anatolii Spesyvyi
- J. Heyrovský Institute of Physical Chemistry of the Czech Academy of Sciences, Dolejškova 2155/3, 18223 Prague 8, Czech Republic.
| | - Patrik Španěl
- J. Heyrovský Institute of Physical Chemistry of the Czech Academy of Sciences, Dolejškova 2155/3, 18223 Prague 8, Czech Republic.
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Wüthrich C, Giannoukos S, Zenobi R. Elucidating the Role of Ion Suppression in Secondary Electrospray Ionization. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2023; 34:2498-2507. [PMID: 37843816 PMCID: PMC10623576 DOI: 10.1021/jasms.3c00219] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Revised: 09/11/2023] [Accepted: 09/29/2023] [Indexed: 10/17/2023]
Abstract
Ion suppression is a known matrix effect in electrospray ionization (ESI), ambient pressure chemical ionization (APCI), and desorption electrospray ionization (DESI), but its characterization in secondary electrospray ionization (SESI) is lacking. A thorough understanding of this effect is crucial for quantitative applications of SESI, such as breath analysis. In this study, gas standards were generated by using an evaporation-based system to assess the susceptibility and suppression potential of acetone, deuterated acetone, deuterated acetic acid, and pyridine. Gas-phase effects were found to dominate ion suppression, with pyridine exhibiting the most significant suppressive effect, which is potentially linked to its gas-phase basicity. The impact of increased acetone levels on the volatiles from exhaled breath condensate was also examined. In humid conditions, a noticeable decrease in intensity of approximately 30% was observed for several features at an acetone concentration of 1 ppm. Considering that this concentration is expected for breath analysis, it becomes crucial to account for this effect when SESI is utilized to quantitatively determine specific compounds.
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Affiliation(s)
- Cedric Wüthrich
- Department
of Chemistry and Applied Biosciences, ETH
Zürich, 8093 Zürich, Switzerland
| | - Stamatios Giannoukos
- Department
of Chemistry and Applied Biosciences, ETH
Zürich, 8093 Zürich, Switzerland
| | - Renato Zenobi
- Department
of Chemistry and Applied Biosciences, ETH
Zürich, 8093 Zürich, Switzerland
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Awchi M, Singh KD, Dill PE, Frey U, Datta AN, Sinues P. Prediction of systemic free and total valproic acid by off-line analysis of exhaled breath in epileptic children and adolescents. J Breath Res 2023; 17:046013. [PMID: 37678210 DOI: 10.1088/1752-7163/acf782] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2023] [Accepted: 09/07/2023] [Indexed: 09/09/2023]
Abstract
Therapeutic drug monitoring (TDM) of medications with a narrow therapeutic window is a common clinical practice to minimize toxic effects and maximize clinical outcomes. Routine analyses rely on the quantification of systemic blood concentrations of drugs. Alternative matrices such as exhaled breath are appealing because of their inherent non-invasive nature. This is especially the case for pediatric patients. We have recently showcased the possibility of predicting systemic concentrations of valproic acid (VPA), an anti-seizure medication by real-time breath analysis in two real clinical settings. This approach, however, comes with the limitation of the patients having to physically exhale into the mass spectrometer. This restricts the possibility of sampling from patients not capable or available to exhale into the mass spectrometer located on the hospital premises. In this work, we developed an alternative method to overcome this limitation by collecting the breath samples in customized bags and subsequently analyzing them by secondary electrospray ionization coupled to high-resolution mass spectrometry (SESI-HRMS). A total ofn= 40 patients (mean ± SD, 11.5 ± 3.5 y.o.) diagnosed with epilepsy and taking VPA were included in this study. The patients underwent three measurements: (i) serum concentrations of total and free VPA, (ii) real-time breath analysis and (iii) off-line analysis of exhaled breath collected in bags. The agreement between the real-time and the off-line breath analysis methods was evaluated using Lin's concordance correlation coefficient (CCC). CCC was computed for ten mass spectral predictors of VPA concentrations. Lin's CCC was >0.6 for all VPA-associated features, except for two low-signal intensity isotopic peaks. Finally, free and total serum VPA concentrations were predicted by cross validating the off-line data set. Support vector machine algorithms provided the most accurate predictions with a root mean square error of cross validation of 29.0 ± 7.4 mg l-1and 3.9 ± 1.4 mg l-1for total and free VPA (mean ± SD), respectively. As a secondary analysis, we explored whether exhaled metabolites previously associated with side-effects and response to medication could be rendered by the off-line analysis method. We found that five features associated with side effects showed a CCC > 0.6, whereas none of the drug response-associated peaks reached this cut-off. We conclude that the clinically relevant free fraction of VPA can be predicted by this combination of off-line breath collection with rapid SESI-HRMS analysis. This opens new possibilities for breath based TDM in clinical settings.
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Affiliation(s)
- Mo Awchi
- University Children's Hospital Basel, Basel, Switzerland
- Department of Biomedical Engineering, University of Basel, Basel, Switzerland
| | - Kapil Dev Singh
- University Children's Hospital Basel, Basel, Switzerland
- Department of Biomedical Engineering, University of Basel, Basel, Switzerland
| | | | - Urs Frey
- University Children's Hospital Basel, Basel, Switzerland
| | | | - Pablo Sinues
- University Children's Hospital Basel, Basel, Switzerland
- Department of Biomedical Engineering, University of Basel, Basel, Switzerland
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Španěl P, Dryahina K, Omezzine Gnioua M, Smith D. Different reactivities of H 3 O + (H 2 O) n with unsaturated and saturated aldehydes: ligand-switching reactions govern the quantitative analytical sensitivity of SESI-MS. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2023; 37:e9496. [PMID: 36807598 DOI: 10.1002/rcm.9496] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Revised: 02/15/2023] [Accepted: 02/17/2023] [Indexed: 06/18/2023]
Abstract
RATIONALE The detection sensitivity of secondary electrospray ionisation mass spectrometry (SESI-MS) is much lower for saturated aldehydes than for unsaturated aldehydes. This needs to be understood in terms of gas phase ion-molecule reaction kinetics and energetics to make SESI-MS analytically more quantitative. METHODS Parallel SESI-MS and selected ion flow tube mass spectrometry (SIFT-MS) analyses were carried out of air containing variable accurately determined concentrations of saturated (C5, pentanal; C7, heptanal; C8 octanal) and unsaturated (C5, 2-pentenal; C7, 2-heptenal; C8, 2-octenal) aldehyde vapours. The influence of the source gas humidity and the ion transfer capillary temperature, 250 and 300°C, in a commercial SESI-MS instrument was explored. Separate experiments were carried out using SIFT to determine the rate coefficients, k73 , for the ligand-switching reactions of the H3 O+ (H2 O)3 ions with the six aldehydes. RESULTS The relative slopes of the plots of SESI-MS ion signal against SIFT-MS concentration were interpreted as the relative SESI-MS sensitivities for these six compounds. The sensitivities for the unsaturated aldehydes were 20 to 60 times greater than for the corresponding C5, C7 and C8 saturated aldehydes. Additionally, the SIFT experiments revealed that the measured k73 are three or four times greater for the unsaturated than for the saturated aldehydes. CONCLUSIONS The trends in SESI-MS sensitivities are rationally explained by differences in the rates of the ligand-switching reactions, which are justified by theoretically calculated equilibrium rate constants derived from thermochemical density functional theory (DFT) calculations of Gibb's free energy changes. The humidity of SESI gas thus favours the reverse reactions of the saturated aldehyde analyte ions, effectively suppressing their signals in contrast to their unsaturated counterparts.
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Affiliation(s)
- Patrik Španěl
- J. Heyrovsky Institute of Physical Chemistry of the Czech Academy of Sciences, Prague, Czechia
| | - Kseniya Dryahina
- J. Heyrovsky Institute of Physical Chemistry of the Czech Academy of Sciences, Prague, Czechia
| | - Maroua Omezzine Gnioua
- J. Heyrovsky Institute of Physical Chemistry of the Czech Academy of Sciences, Prague, Czechia
- Department of Surface and Plasma Science, Faculty of Mathematics and Physics, Charles University, Prague, Czech Republic
| | - David Smith
- J. Heyrovsky Institute of Physical Chemistry of the Czech Academy of Sciences, Prague, Czechia
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Kaeslin J, Wüthrich C, Giannoukos S, Zenobi R. How Soft Is Secondary Electrospray Ionization? JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2022; 33:1967-1974. [PMID: 36111835 DOI: 10.1021/jasms.2c00201] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Secondary electrospray ionization (SESI) mass spectrometry (MS) is a direct infusion technique often used for untargeted metabolomics, e.g., for online breath analysis. SESI is thought to be a soft ionization method, which is important to avoid interference from in-source fragments and to simplify compound annotation. In this work, benzylammonium ions, formed from volatile benzylamines, with known bond dissociation enthalpies were used as thermometer ions to investigate the internal energy distribution of ions that are produced by SESI. It is shown that SESI is softer than electrospray ionization (ESI), and therefore, SESI indeed qualifies as a soft ionization technique. However, we also found that the standard MS instrument settings used in the SESI community are relatively harsh. Proper soft tuning of the instrument is essential to fully benefit from the softness that SESI can provide. Moreover, there is evidence from in-source collision-induced dissociation (CID) experiments that analytes can be solvated in SESI under soft conditions, which supports a recently proposed SESI mechanism referred to as ligand switching.
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Affiliation(s)
- Jérôme Kaeslin
- Department of Chemistry and Applied Biosciences, ETH Zürich, CH-8093 Zürich, Switzerland
| | - Cedric Wüthrich
- Department of Chemistry and Applied Biosciences, ETH Zürich, CH-8093 Zürich, Switzerland
| | - Stamatios Giannoukos
- Department of Chemistry and Applied Biosciences, ETH Zürich, CH-8093 Zürich, Switzerland
| | - Renato Zenobi
- Department of Chemistry and Applied Biosciences, ETH Zürich, CH-8093 Zürich, Switzerland
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Swift SJ, Smith D, Dryahina K, Gnioua MO, Španěl P. Kinetics of reactions of NH 4 + with some biogenic organic molecules and monoterpenes in helium and nitrogen carrier gases: A potential reagent ion for selected ion flow tube mass spectrometry. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2022; 36:e9328. [PMID: 35603529 DOI: 10.1002/rcm.9328] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Revised: 05/19/2022] [Accepted: 05/20/2022] [Indexed: 06/15/2023]
Abstract
RATIONALE To assess the suitability of NH4 + as a reagent ion for trace gas analysis by selected ion flow tube mass spectrometry, SIFT-MS, its ion chemistry must be understood. Thus, rate coefficients and product ions for its reactions with typical biogenic molecules and monoterpenes need to be experimentally determined in both helium, He, and nitrogen, N2 , carrier gases. METHODS NH4 + and H3 O+ were generated in a microwave gas discharge through an NH3 and H2 O vapour mixture and, after m/z selection, injected into He and N2 carrier gas. Using the conventional SIFT method, NH4 + reactions were then studied with M, the biogenic molecules acetone, 1-propanol, 2-butenal, trans-2-heptenal, heptanal, 2-heptanone, 2,3-heptanedione and 15 monoterpene isomers to obtain rate coefficients, k, and product ion branching ratios. Polarisabilities and dipole moments of the reactant molecules and the enthalpy changes in proton transfer reactions were calculated using density functional theory. RESULTS The k values for the reactions of the biogenic molecules were invariably faster in N2 than in He but similar in both bath gases for the monoterpenes. Adducts NH4 + M were the dominant product ions in He and N2 for the biogenic molecules, whereas both MH+ and NH4 + M product ions were observed in the monoterpene reactions; the monoterpene ratio correlating (R2 = 0.7) with the proton affinity, PA, of the monoterpene molecule as calculated. The data indicate that this adduct ion formation is the result of bimolecular rather than termolecular association. CONCLUSIONS NH4 + can be a useful reagent ion for SIFT-MS analyses of molecules with PA(M) < PA(NH3 ) when the dominant single product ion is the adduct NH4 + M. For molecules with PA(M) > PA(NH3 ), such as monoterpenes, both MH+ and NH4 + M ions are likely products, which must be determined along with k by experiment.
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Affiliation(s)
- Stefan James Swift
- J. Heyrovský Institute of Physical Chemistry, Academy of Sciences of the Czech Republic, Prague 8, Czech Republic
| | - David Smith
- J. Heyrovský Institute of Physical Chemistry, Academy of Sciences of the Czech Republic, Prague 8, Czech Republic
| | - Kseniya Dryahina
- J. Heyrovský Institute of Physical Chemistry, Academy of Sciences of the Czech Republic, Prague 8, Czech Republic
| | - Maroua Omezzine Gnioua
- J. Heyrovský Institute of Physical Chemistry, Academy of Sciences of the Czech Republic, Prague 8, Czech Republic
| | - Patrik Španěl
- J. Heyrovský Institute of Physical Chemistry, Academy of Sciences of the Czech Republic, Prague 8, Czech Republic
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11
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Mengers HG, Zimmermann M, Blank LM. Using off-gas for insights through online monitoring of ethanol and baker's yeast volatilome using SESI-Orbitrap MS. Sci Rep 2022; 12:12462. [PMID: 35864195 PMCID: PMC9304407 DOI: 10.1038/s41598-022-16554-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Accepted: 07/12/2022] [Indexed: 11/13/2022] Open
Abstract
Volatile organic compounds play an essential role in every domain of life, with diverse functions. In this study, we use novel 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. While HPLC and Orbitrap measurements show a high agreement for ethanol, acetaldehyde could be measured five hours earlier in the SESI-Orbitrap MS. 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.
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Affiliation(s)
- Hendrik G Mengers
- Institute of Applied Microbiology - iAMB, Aachener Biology and Biotechnology - ABBt, RWTH Aachen University, Aachen, Germany
| | - Martin Zimmermann
- Institute of Applied Microbiology - iAMB, Aachener Biology and Biotechnology - ABBt, RWTH Aachen University, Aachen, Germany
| | - Lars M Blank
- Institute of Applied Microbiology - iAMB, Aachener Biology and Biotechnology - ABBt, RWTH Aachen University, Aachen, Germany.
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Mengers HG, Schier C, Zimmermann M, C. H. Gruhlke M, Block E, Blank LM, Slusarenko AJ. Seeing the smell of garlic: Detection of gas phase volatiles from crushed garlic (Allium sativum), onion (Allium cepa), ramsons (Allium ursinum) and human garlic breath using SESI-Orbitrap MS. Food Chem 2022; 397:133804. [DOI: 10.1016/j.foodchem.2022.133804] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Revised: 07/05/2022] [Accepted: 07/25/2022] [Indexed: 12/01/2022]
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