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Breathomics and its Application for Disease Diagnosis: A Review of Analytical Techniques and Approaches
Published in Raquel Cumeras, Xavier Correig, Volatile organic compound analysis in biomedical diagnosis applications, 2018
David J. Beale, Oliver A. H. Jones, Avinash V. Karpe, Ding Y. Oh, Iain R. White, Konstantinos A. Kouremenos, Enzo A. Palombo
There are various forms of direct injection MS that have been used for the analysis of trace amounts of VOCs such as acetone, acetaldehyde, methanol, ethanol, benzene, toluene, xylene and inorganic gases in air and breath (Lamote et al., 2014). Such methods include secondary electrospray ionization-mass spectrometry (SESI-MS) (Zhu et al., 2013a), proton-transfer-reaction mass spectrometry (PTR-MS) (Zhan et al., 2013), and selected ion flow tube mass spectrometry (SIFT-MS) (Kumar et al., 2013).
The potential of volatile organic compound analysis for pathogen detection and disease monitoring in patients with cystic fibrosis
Published in Expert Review of Respiratory Medicine, 2022
Anton Barucha, Renan M. Mauch, Franziska Duckstein, Carlos Zagoya, Jochen G. Mainz
A new study has recently suggested combining secondary electrospray ionization high-resolution mass spectrometry (SESI-HRMS) with machine-learning analyses, as a promising tool to achieve this goal. This approach could successfully differentiate between P. aeruginosa, Streptococcus pneumoniae, S. aureus, Haemophilus influenzae, Escherichia coli, and Stenotrophomonas maltophilia based on their VOC profiles [47]. Although this study has taken an important step towards improving the specificity of VOC-based methods, future analyses should focus on the differentiation between P. aeruginosa and other common and emerging CF pathogens, such as Achromobacter xylosoxidans, nontuberculous mycobacteria (NTM) and Bcc, which are well known for enhancing inflammation and lung function decline. The latter have been associated with life-threatening conditions such as cepacia syndrome and bacteremia [48–50]. Furthermore, chronically colonizing Bcc are difficult to eradicate due to their intrinsic resistance to commonly used antibiotics, which has been observed to be higher than that for P. aeruginosa [51–53]. Consequently, intensive efforts have been paid to the understanding of Bcc virulence determinants [49,54]. Likewise, future VOC research should consider detection and differentiation of critical pathogens like NTM, Achromobacter xylosoxidans and Bcc as an important aim in future VOC research. In this regard, with the rapid development of semiconductor technologies and machine learning algorithms, electronic noses have recently become promising technologies for the detection and differentiation of pulmonary diseases [55–58]. Interestingly, recent studies comparing the performance of e-noses and GC-MS analyses have shown e-noses to achieve better performances [59,60].
Noninvasive monitoring of fibre fermentation in healthy volunteers by analyzing breath volatile metabolites: lessons from the FiberTAG intervention study
Published in Gut Microbes, 2021
Audrey M. Neyrinck, Julie Rodriguez, Zhengxiao Zhang, Benjamin Seethaler, Florence Mailleux, Joeri Vercammen, Laure B. Bindels, Patrice D. Cani, Julie-Anne Nazare, Véronique Maquet, Martine Laville, Stephan C. Bischoff, Jens Walter, Nathalie M. Delzenne
Usually, the analysis of exhaled breath biomarkers is carried out by means of gaz chromatography-mass spectrometry (GC-MS), preferably in combination with a suitable enrichment technique prior to analysis. Although very powerful, GC-MS is not particularly compatible with routine clinical practice. It is a relatively slow technique, requiring analysis times that take on average 30–45 min for comprehensive analysis without post-run data processing.13 Alternatively, direct MS techniques such as selected ion flow tube (SIFT)-MS, proton transfer reaction (PTR)-MS and more recently secondary electrospray ionization (SESI) MS have gained more attention because they hold the promise of speed, selectivity, and sensitivity in a single instrument.14 SIFT-MS is particularly well suited for the purpose of exhaled breath analysis.15 It combines very soft chemical ionization under controlled conditions with three precursor ions (H3O+, NO+, and O2+), preserving molecular ion integrity for maximum sensitivity and selectivity. Precursor ions are generated in situ from humidified air that is gently fed into a high energy microwave discharge source to create an ion plasma. Selected precursor ions are extracted from this plasma by means of a short upstream quadrupole and introduced in the flow tube, where they are thermalized by means of a high flow of helium and allowed to react with the sample molecules for a defined amount of time. During the reaction, formed product ions are diverted toward a downstream quadrupole by means of the excess helium flow where they are separated from each other and detected. Since reaction conditions are accurately controlled, SIFT-MS allows direct quantification of target components in real-time from raw ion count rates and associated reaction kinetics. Typical concentration levels are situated at low parts per billion by volume levels. Of note, the applied precursor ions are very effective in ionizing a broad range of organic and inorganic components but they do not react with nitrogen, oxygen and carbon dioxide. Usually, SIFT-MS is applied in target mode, which means that only a limited set of components are measured simultaneously.15 If target components are not known, SIFT-MS is used in untargeted scan mode, where it provides pattern-based classification capacity, the identification of probable biomarkers, and retrospective quantification of target components.16