Jamil Khirbek Jamil Khirbek

Preservation of exhaled breath samples for analysis by off-line SESI-HRMS: proof-of-concept study

Rosa A Sola-Martínez, Jiafa Zeng, Mo Awchi, Amanda Gisler, Kim Arnold, Kapil Dev Singh, Urs Frey, Manuel Cánovas Díaz, Teresa de Diego Puente, Pablo Sinues

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…

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Fatima Diakhate Fatima Diakhate

Globally optimized targeted secondary electrospray ionization high resolution mass spectrometry (dGOT-SESI-HRMS) and spectral stitching enhanced volatilomics analysis of bacterial metabolites

Fouad Choueiry, Rui Xu, Kelly Meyrath, Jiangjiang Zhu.

Secondary electrospray ionization high-resolution mass spectrometry (SESI-HRMS) is an innovative analytical technique for the rapid and non-invasive analysis of volatile organic compounds (VOCs). However, compound annotation and ion suppression in the SESI source has hindered feature detection, stability and reproducibility of SESI-HRMS in untargeted volatilomics.

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Jamil Khirbek Jamil Khirbek

Secondary-Electrospray Ionization Mass Spectrometry-Based Online Analyses of Mouse Volatilome Uncover Gut Microbiome-Dictated Metabolic Changes in the Host

Fouad Choueiry, Andrew Gold, Rui Xu, Shiqi Zhang and Jiangjiang Zhu.

The symbiotic relationship between the gut microbial population is capable of regulating numerous aspects of host physiology, including metabolism. Bacteria can modulate the metabolic processes of the host by feeding on nutritional components within the lumen and releasing bioactive components into circulation. Endogenous volatile organic compound (VOC) synthesis is dependent on the availability of precursors found in mammalian metabolism

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Jamil Khirbek Jamil Khirbek

Elucidating the Role of Ion Suppression in Secondary Electrospray Ionization

Cedric Wüthrich, Stamatios Giannoukos, Renato Zenobi

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…

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Jamil Khirbek Jamil Khirbek

Prediction of systemic free and total valproic acid by off-line analysis of exhaled breath in epileptic children and adolescents

Mo Awchi, Kapil Dev Singh, Patricia E Dill, Urs Frey, Alexandre N Datta, and Pablo Sinues.

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

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Jamil Khirbek Jamil Khirbek

Direct Mass Spectrometric Analysis of Exhaled Breath: Advances towards Clinical Application

Bettina Streckenbach

Metabolomics, or the comprehensive study of metabolites and involved processes, provides insights into the current physiological state of humans. In the clinical setting, the detection and quantification of specific metabolites has proven to be invaluable in diagnostic testing. Herein, body samples that are non-invasively accessible are of particular interest…

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Fatima Diakhate Fatima Diakhate

Exhaled volatile fatty acids, ruminal methane emission and their diurnal patterns in lactating dairy cows

M.Z. Islam, S. Giannoukos, Räisänen, K. Wang, X. Ma, F. Wahl, R. Zenobi, M. Niu.

To date, the commonly used methods to assess rumen fermentation are invasive. Exhaled breath contains hundreds of volatile organic compounds (VOC) that can reflect animal physiological processes. In the present study, for the first time, we aimed to use a non-invasive metabolomics approach based on high-resolution mass spectrometry to identify rumen fermentation parameters in dairy cows

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Fatima Diakhate Fatima Diakhate

Different reactivities of H3O+(H2O)n with unsaturated and saturated aldehydes: ligand-switching reactions govern the quantitative analytical sensitivity of SESI-MS

Patrik Španěl, Kseniya Dryahina, Maroua Omezzine Gnioua, David Smith

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.

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Jamil Khirbek Jamil Khirbek

Real-Time Volatile Metabolomics Analysis of Dendritic Cells

Kim Arnold, Philippe Dehio, Jonas Lötscher, Kapil Dev Singh, Diego García-Gómez, Christoph Hess, Pablo Sinues, and Maria L. Balmer

Dendritic cells (DCs) actively sample and present antigen to cells of the adaptive immune system and are thus vital for successful immune control and memory formation. Immune cell metabolism and function are tightly interlinked, and a better understanding of this interaction offers potential to develop immunomodulatory strategies. However, current approaches for assessing the immune cell metabolome are often limited by endpoint measurements, may involve laborious sample preparation, and may lack unbiased, temporal resolution of the metabolome. In this study, we present a novel setup coupled to a secondary electrospray ionization-high resolution mass spectrometric (SESI-HRMS) platform allowing headspace analysis of immature andactivated DCs in real-time with minimal sample preparation and intervention, with high technical reproducibility and potential for automation.

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Fatima Diakhate Fatima Diakhate

UHPLC-MS/MS-Based Identity Confirmation of Amino Acids Involved in Response to and Side Effects from Antiseizure Medications

Mo Awchi, Pablo Sinues, Alexandre N. Datta, Diego García-Gómez, and Kapil Dev Singh

Real-time breath analysis using secondary electrospray ionization coupled with high-resolution mass spectrometry is a fast and noninvasive method to access the metabolic state of a person. However, it lacks the ability to unequivocally assign mass spectral features to compounds due to the absence of chromatographic separation. This can be overcomed by using exhaled breath condensate and conventional liquid chromatography–mass spectrometry (LC–MS) systems.

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