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…

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…

Xin Xu, Hongwei Pang, Chao Liu, Kangyi Wang, Gwendal Loisel, Lei Li, Sasho Gligorovski, Xue Li

Human presence can affect indoor air quality because of secondary organic compounds formed upon reactions between gaseous oxidant species, e.g., ozone (O₃), hydroxyl radicals (OH), and chemical compounds from skin, exhaled breath, hair and clothes. We assess the gas-phase product compounds generated by reactions of gaseous O₃ with volatile organic compounds (VOCs) from exhaled human breath…

Huifan Deng, Xin Xu, Kangyi Wang, Jinli Xu, Gwendal Loisel, Yiqun Wang, Hongwei Pang, Pan Li, Zebin Mai, Shichao Yan, Xue Li,Sasho Gligorovski

The primarily emitted compounds by human presence, e.g., skin and volatile organic compounds (VOCs) in breath, can react with typical indoor air oxidants, ozone (O₃), and hydroxyl radicals (OH), leading to secondary organic compounds…

Huifan Deng, Pascale S. J. Lakey, Yiqun Wang, Pan Li, Jinli Xu, Hongwei Pang, Jiangping Liu, Xin Xu, Xue Li, Xinming Wang, Yuzhong Zhang, Manabu Shiraiwa, and Sasho Gligorovski

The reactions of sulfur dioxide (SO₂) with surface-bound compounds on atmospheric aerosols lead to the formation of organic sulfur (OS) compounds, thereby affecting the air quality and climate. Here, we show that the heterogeneous reaction of SO₂ with authentic urban grime under near-ultraviolet sunlight irradiation leads to a large suite of various organic compounds including OS released in the gas phase…

Yiqun Wang, Huifan Deng, Pan Li, Jinli Xu, Gwendal Loisel, Hongwei Pang, Xin Xu, Xue Li, Sasho Gligorovski

Little is known about the processes of formation of the secondarily formed N-containing organics in the atmosphere. Here, we investigated the formation of gas-phase organic compounds, including N-containing organics, through interfacial oxidation chemistry of gaseous O₃ with an authentic riverine surface microlayer (SML) by using a high-resolution quadrupole Orbitrap mass spectrometer coupled to a secondary electrospray ionization source…