<p>Grasslands comprise natural tropical savannah over managed temperate fields to tundra and cover one quarter of the Earth&#39;s land surface. Plant growth, maintenance and decay result in volatile organic compound (VOCs) emissions to the atmosphere. Furthermore, biogenic VOCs (BVOCs) are emitted as a consequence of various environmental stresses including cutting and drying during harvesting. Fluxes of BVOCs were measured with a proton-transfer-reaction-mass-spectrometer (PTR-MS) over temperate mountain grassland in Stubai Valley (Tyrol, Austria) over one growing season (2008). VOC fluxes were calculated from the disjunct PTR-MS data using the virtual disjunct eddy covariance method and the gap filling method. Methanol fluxes obtained with the two independent flux calculation methods were highly correlated (y = 0.95&times;-0.12, R (2) = 0.92). Methanol showed strong daytime emissions throughout the growing season - with maximal values of 9.7 nmol m(-2) s(-1), methanol fluxes from the growing grassland were considerably higher at the beginning of the growing season in June compared to those measured during October (2.5 nmol m(-2) s(-1)). Methanol was the only component that exhibited consistent fluxes during the entire growing periods of the grass. The cutting and drying of the grass increased the emissions of methanol to up to 78.4 nmol m(-2) s(-1). In addition, emissions of acetaldehyde (up to 11.0 nmol m(-2) s(-1)), and hexenal (leaf aldehyde, up to 8.6 nmol m(-2) s(-1)) were detected during/after harvesting.</p>

We analysed the exhaled breath of a cohort of 50 healthy women using Proton-Transfer-Reaction Time-of-Flight Mass Spectrometry (PTR-TOF-MS). To ensure that end-tidal exhaled air was collected, we used a Breath Collecting Unit, which sampled breath gas only when the CO2 signal was high. Samples were stored in inert Silco cans and analysed subsequently by PTR-TOF-MS. Components are characterized by their sum formula and were extracted from the raw data by matching them with a list of candidate compounds. A description of the average composition of the investigated cohort is given. These data can be helpful to identify compounds in breath measurements with quadrupole PTRMS systems, where a separation of isobaric compounds is not possible.

We analysed the exhaled breath of a cohort of 50 healthy women using Proton-Transfer-Reaction Time-of-Flight Mass Spectrometry (PTR-TOF-MS). To ensure that end-tidal exhaled air was collected, we used a Breath Collecting Unit, which sampled breath gas only when the CO2 signal was high. Samples were stored in inert Silco cans and analysed subsequently by PTR-TOF-MS. Components are characterized by their sum formula and were extracted from the raw data by matching them with a list of candidate compounds. A description of the average composition of the investigated cohort is given. These data can be helpful to identify compounds in breath measurements with quadrupole PTRMS systems, where a separation of isobaric compounds is not possible.

In a clinical screening study we have measured several hundred subjects using real-time breath analysis with PTR-MS. We present and discuss potential breath markers for lung cancer with a critical view on the data analysis. The presented problems and solutions are also applicable to other analytical methods used in breath analysis.

Typical clinical (breath analysis) studies take several months to years. Employing a Proton-Transfer-Reaction Time-of-Flight Mass Spectrometer (PTR-TOF-MS) as an analytical tool for breath analysis, a constant performance of the instrument is essential. Here we report on the longterm performance of a PTR-TOF-MS for the analysis of exhaled breath gas in the frame of a clinical study. Performance data are shown for a period of 7 months. We characterized the sampling procedure, sample storage, and measured sensitivity and detection limit for a set of VOCs with relevance in breath analysis. Over the period of 7 months, we were able to achieve a high mass accuracy and precision in the range of ppm.

Typical clinical (breath analysis) studies take several months to years. Employing a Proton-Transfer-Reaction Time-of-Flight Mass Spectrometer (PTR-TOF-MS) as an analytical tool for breath analysis, a constant performance of the instrument is essential. Here we report on the longterm performance of a PTR-TOF-MS for the analysis of exhaled breath gas in the frame of a clinical study. Performance data are shown for a period of 7 months. We characterized the sampling procedure, sample storage, and measured sensitivity and detection limit for a set of VOCs with relevance in breath analysis. Over the period of 7 months, we were able to achieve a high mass accuracy and precision in the range of ppm.

Common bioprocess conditions imply a gas-liquid-mixture with living cells as solid phase in a sterile environment which demands a great deal on sensor/analyzer technology and design. Online access to physiology relevant process variables, the ultimate request of process engineers, is still very limited as complexity of biological systems additionally constrains direct measurements...

Die Zusammensetzung der Atemluft kann durch Erkrankungen verändert werden. Mit Hilfe von modernen analytischen Messmethoden versucht die Forschung, Zusammenhänge ­zwischen einzelnen Chemikalien und physiologischen bzw. pathologischen Vorgängen fest­zustellen. Ziel ist die nicht-invasive Frühdiagnostik von Krankheiten durch Atemgasanalysen. In einer Pilotstudie an der Innsbrucker Universitäts-Fraukenklinik wurden Atemgasproben von Brustkrebspatientinnen systematisch mit einer hochempfindlichen Methode analysiert. Eine ­signifikante ­Erniedrigung der Isopren-Konzentration der ausgeatmeten Luft vs. gesunde Kontrollen ist konsistent mit den ­Ergebnissen von Atemgasstudien bei Lungenkrebspatientinnen.

Mass spectrometry is a well-known technology to detect O2 and CO2 in the off-gas of cell culture fermentations. In contrast to classical spectrometers, the proton transfer reaction mass spectrometer (PTR-MS) applies a very soft ionization strategy and therefore the spectra show less fragments and are easier to interpret. In our study we applied the PTR-MS technology to monitor volatile organic compounds (VOC) in mammalian cell culture processes. Interesting masses were identified and correlations between PTR-MS data and off-line parameters will be presented.

We report on the search for low molecular weight molecules-possibly accumulated in the bloodstream and body-in the exhaled breath of uremic patients with kidney malfunction. We performed non-invasive analysis of the breath gas of 96 patients shortly before and several times after kidney transplantation using proton-transfer-reaction mass spectrometry (PTR-MS), a very sensitive technique for detecting trace amounts of volatile organic compounds. A total of 642 individual breath analyses which included at least 41 different chemical components were carried out. Correlation analysis revealed one particular breath component with a molecular mass of 114 u (unified atomic mass units) that clearly correlated with blood serum creatinine, which is the currently accepted marker for assessing the function of the kidney. In particular, daily urine production showed good correlation with the identified breath marker. An independent set of seven samples taken from three patients at the onset of dialysis and three controls with normal kidney function confirmed a significant difference in concentration between patients and controls for a compound with a molecular mass of 114.1035 u using high mass resolving proton-transfer-reaction time-of-flight mass spectrometry (PTR-TOF-MS). A chemical composition of CHO was derived for the respective component. Fragmentation experiments on the same samples using proton-transfer-reaction triple-quadrupole tandem mass spectrometry (PTR-QqQ-MS) suggested that this breath marker is a C-ketone or a branched C-aldehyde. Non-invasive real-time monitoring of the kidney function via this breath marker could be a possible future procedure in the clinical setting.

Breath gas analysis is an emerging field that attempts to link components in exhaled breath gas with state-of-health or illness [1]. This is based on the premise that disease in the body will elicit abnormal biochemical reactions which in turn produce chemical compounds that might be excreted by the body - at least in part - via exhalation. We used PTR-MS to directly sample and analyse selected VOC constituents in the exhaled breath of patients (n=96) undergoing kidney transplantation. Breath samples were taken before surgery and then over an extended period thereafter. Comparison of PTR-MS data with routine blood-serum data revealed a specific compound (ion trace) at m/z 115 that correlated with creatinine in blood serum and daily urine production, which are the current generally-accepted markers for kidney function. PTR-TOF analyses revealed that this compound had an exact molecular mass of 114.104 u and a chemical composition of C7H14O. Subsequent analyses using PTR-QqQ-MS suggested the compound to be a C7-ketone or branched C7-aldehyde. It is hoped that the results of this study will provide impetus to other researchers in the field to further delve into the nature of this compound and its possible biochemical production routes to ascertain the eligibility of this compound for potential use in future routine breath analysis for renal function assessment.