A. Gisler, K. D. Singh, A. Marten, F. Decrue, U. Frey, P. Sinues and J. Usemann

Real-time breath analysis via secondary electrospray ionization high-resolution mass spectrometry (SESI-HRMS) shows promise as a non-invasive tool for assessing oxidative stress. In a study involving 128 children (25 tobacco smoke-exposed, 103 non-exposed), 71 breath features significantly correlated with urinary levels of the oxidative stress marker 8-iso-prostaglandin F2α (8-iso-PGF2α). Breath analysis moderately predicted urinary 8-iso-PGF2α (concordance correlation: 0.37 ± 0.05), suggesting potential clinical applicability

Zhifeng Tang, Jianming Yang, Xin Xu, Keda Zhang, Huiling Wang, Xin Luo, Mingliang Fang, Tao Huan, Xue Li

Breath metabolomics enables noninvasive and rapid acquisition of metabolic information by detecting volatile organic compounds (VOCs) in exhaled breath. Secondary electrospray ionization high-resolution tandem mass spectrometry (SESI-HRMS/MS) offers the highest coverage for detecting breath metabolites among current real-time breath analysis techniques. Although it has been generally recognized that metabolites in breath originate from the blood, a molecular-level understanding of the characteristics of metabolites in both breath and blood remains insufficient. In this study, nontargeted analyses of breath and blood samples from 11 healthy volunteers were performed using SESI-HRMS/MS and ultrahigh performance liquid chromatography electrospray ionization high-resolution tandem mass spectrometry (UHPLC-ESI-HRMS/MS), respectively…

P. Sinues, M. Richard, K. Singh, D. Sezer, S. Buergler, L. Palermo, Y. Schulz, Z. Tang, X. Luo, U. Frey, P. Cattin, X. Li, J. Gaab

Accurately assessing pain in vulnerable populations—such as children, the elderly, and unconscious patients—remains a critical challenge in healthcare. A new study explores the potential of breath metabolomics as a real-time, objective tool for pain evaluation. Using the cold pressor test (CPT) to induce pain, researchers analyzed exhaled breath with high-resolution mass spectrometry, identifying over 400 metabolic changes within 15 minutes. Key pathways linked to pain signaling, including amino acid metabolism and neurotransmitter activity, showed significant shifts. A neural network classifier effectively distinguished pre- and post-CPT states (AUC=0.856), highlighting the promise of this approach. These findings align with chronic pain research, suggesting a deeper metabolic connection to pain perception. This breakthrough paves the way for observer-independent pain monitoring, with future research needed to tailor insights for personalized pain management strategies.

Kim Arnold, Alejandro Gómez-Mejia, Miguel de Figueiredo, An N. T. Phan, Roy Eerlings, Hendrik G. Mengers & Lars M. Blank

Here, we demonstrated the secondary electrospray ionization coupled Orbitrap mass spectrometry (SESI-Orbitrap MS) methodology for quantifying tulipalin A release from plants upon injury.

Kim Arnold, Alejandro Gómez-Mejia, Miguel de Figueiredo, Julien Boccard, Kapil Dev Singh, Serge Rudaz, Pablo Sinues & Annelies S. Zinkernagel

This study refines the application of the non-invasive Secondary Electrospray Ionization-High Resolution Mass Spectrometry (SESI-HRMS) methodology for real-time and early detection of human respiratory bacterial pathogens in the respiratory tract of a mouse infection model

Sarah Basler, Noriane A Sievi, Felix Schmidt, Kai Fricke, Alexandra Arvaji, Jonas Herth, Diego M Baur, Pablo Sinues, Silvia Ulrich and Malcolm Kohler

Metabolic changes in the linoleate, tyrosine, and tryptophan pathways during AECOPD were predominant. Significant metabolic changes occur during COPD exacerbations, predominantly in the linoleate, tyrosine, and tryptophan pathways, which are all linked to inflammation. Real-time exhaled breath analysis enables a good prediction of AECOPD compared to stable state and thus could enhance precision of AECOPD diagnosis and efficacy in clinical practice.

Wolfram Miekisch, Pritam Sukul, Jochen K. Schubert

As dynamic VOC profiling provides valuable information on kinetics of markers and confounders, it offers huge and so far unexplored potential for physiological, metabolic, therapeutic and environmental monitoring. Driven by new and innovative technologies such as real time mass spectrometry and highly specific sensor systems, future applications may range from home care to ICU monitoring

Siyu Liu, Jinli Xu, Yingxin Xie, Bowen He, Qingxin Deng, Yanan Hu, Jiangping Liu, Davide Vione, Xue Li, Sasho Gligorovski

Real-time measurements of the gas-phase product compounds formed by the reaction of O₃ with BDE-209 were performed with a SESI-HRMS in both positive and negative ionization modes…

Yukai Wang, Zhifeng Tang, Tingting Zhao, Jianming Yang, Wei Zhang, Xue Li, Tao Huan

This work takes a typical real-time HRMS technique as an example, i.e. secondary electrospray ionization high-resolution mass spectrometry (SESI-HRMS), and presents BreathXplorer, an open-source Python package designed for the processing of real-time exhaled breath data comprising multiple exhalations. BreathXplorer is composed of four main modules…

Cedric Wüthrich, Timon Käser, Renato Zenobi, Stamatios Giannoukos

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.

Cedric Wüthrich，Albin Vadakkechira，Pascal Fuchsmann，Simon Wacker，Renato Zenobi, and Stamatios Giannouko

Secondary electrospray ionization coupled to high-resolution mass spectrometry (SESI-HRMS) is a powerful method for the analysis of exhaled breath in real time. However, feature annotation is challenging due to the flow-injection nature of the technique. To evaluate alternative methods for enhancing feature annotation, a study was conducted where…

Jonas Herth, Felix Schmidt, Sarah Basler, Noriane A Sievi and Malcolm Kohler

Exhaled breath analysis has emerged as a non-invasive and promising method for early detection of lung cancer, offering a novel approach for diagnosis through the identification of specific biomarkers present in a patient's breath…

Chen Tao, Peter Mettke, Yaru Wang, Xue Li, Ligang Hu

Highlights

• Near-surface ozone pollution has a significant impact on respiratory health.

• Lung microenvironment is involved in respiratory health effects of ozone pollution.

• Exhalation metabolomics provides a new method to explore the respiratory health effects of ozone pollution.

• Exhalation metabolomics could be a potential basis for concentration limits in ozone pollution control.

Cedric Wüthrich, Renato Zenobi, Stamatios Giannoukos

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….

WANG Kangyi, TAO Chen, LUO Zuo, TANG Zhifeng, BAI Te, LI Hang, HU Ligang, ZHANG Zuo, LI Xue

Breath samples can be collected from the oral and nasal cavity.However,the oral and nasal environment affect the chemical composition of breath sample. It was found that the number of unique component(m/z)detected in mouth-exhaled breath(167)was 2.2 times greater than that detected in nose-exhaled breath(76), which might result from the complex environment in oral cavity. The signal intensity of common component (163) was significantly different between mouth-exhaled breath and nose-exhaled breath. Additionally, the elemental composition analysis showed that the proportion of polar compounds detected in nose-exhaled breath was higher than that in mouth-exhaled breath. This study demonstrated that there was significant differences in the chemical composition between mouth-exhaled and nose-exhaled breath, which provided a theoretical basis for selection of exhalation mode.

Stamatios Giannoukos, Cedric Wüthrich

This review discusses the technical aspects behind SESI, the advancements, and the technical hurdles faced. Additionally, the recent advances in the applications of SESI in human and animal-centered research are presented.

Wei Liu, Li Zhou, Wenting Yuan, Ling Ruan, Xinkai Wang, Yucong Guo, Zhouqing Xie, Qifan Liu, Chen Wang

This review article summarizes the principles of different online mass spectrometry techniques and their application to indoor VOC measurements. The sources, emission characteristics, and chemical compositions of primary indoor VOCs are discussed. Recent advances in the fundamental understanding of chemical transformations and formation mechanisms related to secondary indoor VOCs are also discussed

Hui Huang, Jianming Yang, Chen Tao, Ligang Hu, Tao Huan, Wei Zhang, Keda Zhang, Xue Li

Exhaled breath is a promising specimen for in vivo drug analysis. The analysis of non-volatile drugs (NVDs) in exhaled breath is especially valuable due to the clinical prevalence of NVDs…

This review thoroughly describes the origin of NVDs in exhaled breath, and summarizes the characteristics and limitations of current analytical methods for exhaled NVDs, as well as the applications of breath analysis for NVDs, in order to provide helpful guidance for subsequent basic and translational research.

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…

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…