Xue Li, Lei Huang, Hui Zhu and Zhen Zhou.

RATIONALE: Direct mass spectrometry (MS)-based methods make it possible to monitor the molecular compositions of hundreds of volatile organic compounds (VOCs) in exhaled human breath in real time. Mass resolution and mass accuracy play important roles for direct MS analysis, especially for the low-concentration isobaric compounds in non-target research.

D. García-Gómez, T. Gaisl, L. Bregy, A. Cremonesi, P. M-L Sinues, M. Kohler, and R. Zenobi

Amino acids are frequently determined in clinical chemistry. However, current analysis methods are time-consuming, invasive, and require sample preparation. The authors hypothesized that plasma concentrations of amino acids can be estimated by measuring their concentrations in exhaled breath.

D. García-Gómez, T. Gaisl, L. Bregy, P. M-L Sinues, M. Kohler and R. Zenobi

Disorders in tryptophan metabolism result in diseases such as vitamin B6 responsive xanthurenic aciduria, hydroxy-kynureninuria, tryptophanuria and Hartnup disease. The authors hypotesized that breath analysis may reveal compounds that are metabolically linked to tryptophan. The mass range of detected metabolites reached up to 265 u, which is beyond the mass range limit (150–200 u) of competing breath research techniques such as PTR or SIFT-MS.

G. Trecate, P. M-L Sinues & R. Orlandi

Breast cancer screening and presurgical diagnosis are currently based on mammography, ultrasound and more sensitive imaging technologies; however, noninvasive biomarkers represent both a challenge and an opportunity for early detection of cancer …

M. T. Gaugg, D. Garcia Gomez, C. Barrios-Collado, G. Vidal-de-Miguel, M. Kohler, R. Zenobi and P. M-L Sinues

Coupling a SESI source and a HRMS (Orbitrap), the authors were able to identify exogenous compounds associated to smoking, as well as endogenous metabolites suggesting increased oxidative stress in smokers. According to the authors, most of these compounds correlated significantly with smoking frequency and allowed accurate discrimination of smokers and non-smokers.

D. Garcia-Gomez, T. Gaisl, C. Barrios-Collado, Guillermo Vidal-de-Miguel, M. Kohler and R. Zenobi

Chemical analysis of aerosols collected from electronic cigarettes (ECs) has shown that these devices produce vapors that contain harmful and potentially harmful compounds. Conventional analytical methods used for the analysis of electronic cigarettes do not reflect the actual composition of the aerosols generated because they usually neglect the changes in the chemical composition that occur during the aerosol generation process and after collection.

C. Barrios-Collado, D. Garcia-Gomez, R. Zenobi, G. Vidal-de-Miguel, Alfredo J. Ibanez, and P. M-L Sinues

The authors document how hundreds of species can be tracked with an unparalleled time resolution of 2 min during day−night cycles. To further illustrate the capabilities of SESI-MS for volatile organic compounds (VOCs) analysis, they subjected the plant to mechanical damage and monitored its response.

E. I Schwarz, P. M-L Sinues, L. Bregy, T. Gaisl, D. Garcia-Gomez, M. T. Gaugg, Y. Suter, N. Stebler, Y. Nussbaumer-Ochsner, K. E. Bloch, J. R. Stradling, R. Zenobi, M. Kohler

Patients with OSA effectively treated with CPAP were randomised to either withdraw treatment or continue CPAP for 2 weeks. Exhaled breath analysis and research by untargeted SESI-MS was performed at baseline and 2 weeks after randomisation. CPAP withdrawal led to a recurrence of OSA, which was accompanied by a significant change in 16 identified metabolites.

Matthew J. Aernecke, Ted Mendum, Geoff Geurtsen, Alla Ostrinskaya, Roderick R. Kunz*

A rapid method for vapor pressure measurement was developed and used to derive the vapor pressure curve of the thermally labile peroxide-based explosive.

L. Bregy, A. R. Müggler, P. M-L Sinues, D. García-Gómez, Y. Suter, G. N. Belibasakis, M. Kohler, P. R. Schmidlin, Renato Zenobi

The detection of bacterial-specific volatile metabolites may be a valuable tool to predict infection. Here we applied a real-time mass spectrometric technique to investigate differences in volatile metabolic profiles of oral bacteria that cause periodontitis. We coupled a secondary electrospray ionization (SESI) source to a commercial high-resolution mass spectrometer …

P. M-L Sinues, Elena Landoni, Rosalba Miceli, Vincenza F. Dibari, Matteo Dugo, Roberto Agresti, Elda Tagliabue, Simone Cristoni, Rosaria Orlandi.

SESI–MS produces high-dimensional data of quality comparable to gene expression analysis output. This prompted the authors to use methods originally developed for gene expression data in analyzing SESI–MS breathprints.

D. García-Gómez, L. Bregy, Y. Nussbaumer-Ochsner, T. Gaisl, M. Kohler, and R. Zenobi

2-Subtituted benzothiazoles are widely used industrial chemicals whose occurrence in environmental samples has been shown to be ubiquitous. However, knowledge about human exposure to these compounds and their excretion route is still scarce. Here, we demonstrate for the first time the detection of benzothiazole derivatives in exhaled breath.

C. Barrios-Collado, G. Vidal-de-Miguel, P. M-L Sinues

The process by which ambient vapors are ionized upon interaction with electrosprays is not fully under-stood, compromising its optimization and widespread use. In this work we evaluated the different scales associated with the processes involved in secondary electrospray ionization (SESI) and developed a new numerical method …

D. García-Gómez, L. Bregy, C. Barrios-Collado, G. Vidal-de-Miguel and R. Zenobi

The identification of chemical compounds in exhaled human breath is promising in the search for new biomakers of diseases. However, the analytical techniques used nowadays are not capable of achieving a robust identification, especially in real-time analysis.

Alex R. Hill, Mark Edgar, Maria Chatzigeorgiou, James C. Reynolds, Paul F. Kelly* and Colin S. Creaser*

The complexation of triacetone triperoxide (TATP) with a range of alkali metals has been studied by electrospray ionisation mass spectrometry to yield [M + Cat]+ ions for all of the alkali metals. The formation of [2TATP + Li + LiX]+ (X = Br, Cl) sandwich complexes was also observed. Collision cross-sections for the lithium-containing complexes of TATP were measured by travelling wave ion mobility spectrometry mass spectrometry and compared well with computationally determined structures. Extractive electrospray ionisation (EESI) using a lithium-doped electrospray is demonstrated for the detection of TATP vapours desorbed from a metal surface. The limit of detection for EESI was shown to be 20 ng using the [TATP + Li]+ ion.

Xue Li, P. M-L Sinues, R. Dallmann, L. Bregy, M.Hollmén, S. Proulx, S. A. Brown, M. Detmar, M. Kohler, and R. Zenobi

Noninvasive, real-time pharmacokinetic (PK) monitoring of ketamine, propofol, and valproic acid, and their metabolites was achieved in mice, using secondary electrospray ionization and high-resolution mass spectrometry. The PK profile of a drug influences its efficacy and toxicity because it determines exposure time and levels …

H. D. Bean, T. R. Mellors, J. Zhu and J. E. Hill

A number of direct injection mass spectrometry methods that can sample foods nondestructively and without sample preparation are being developed with applications ranging from the rapid assessment of food safety to the verification of protected designations of origin. In this pilot study, SESI-MS in positive and negative-ion modes was used to …

D. García-Gómez, P. M.-L. Sinues, C. Barrios-Collado, G. Vidal-de Miguel, M. Gaugg, and R. Zenobi

In recent years, breath analysis in real time has become a noninvasive alternative for the diagnosis of diseases and for molecular fingerprinting of exhaled breath. However, the techniques used lack the capabilities for proper identification of the compounds found in the exhalome.

P. M-L Sinues, L. Tarokh, Xue Li, M. Kohler, S. A. Brown, R. Zenobi, R. Dallmann

Circadian clocks play a significant role in the correct timing of physiological metabolism, and clock disruption might lead to pathological changes of metabolism. One interesting method to assess the current state of metabolism is metabolomics. Metabolomics tries to capture the entirety of small molecules, i.e. the building blocks of metabolism, in a given matrix …

J-C Wolf, M. Schaer, P. Siegenthaler, R. Zenobi

A novel active capillary dielectric barrier discharge plasma ionization (DBDI) technique for mass spectrometry is applied to the direct detection of thirteen chemical warfare related compounds, including sarin, and compared to secondary electrospray ionization (SESI) in terms of selectivity and sensitivity.