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[Warneke2006] Warneke, C., JA. De Gouw, A. Stohl, OR. Cooper, PD. Goldan, WC. Kuster, JS. Holloway, EJ. Williams, BM. Lerner, SA. McKeen, et al., "Biomass burning and anthropogenic sources of CO over New England in the summer 2004", Journal of geophysical research, vol. 111, no. D23: American Geophysical Union, pp. D23S15, 2006.
Link: http://www.agu.org/pubs/crossref/2006/2005JD006878.shtml
Abstract
During the summer of 2004 large wildfires were burning in Alaska and Canada, and part of the emissions were transported toward the northeast United States, where they were measured during the NEAQS-ITCT 2k4 (New England Air Quality Study–Intercontinental Transport and Chemical Transformation) study on board the NOAA WP-3 aircraft and the NOAA research vessel Ronald H. Brown. Using acetonitrile and chloroform as tracers the biomass burning and the anthropogenic fraction of the carbon monoxide (CO) enhancement are determined. As much as 30% of the measured enhancement is attributed to the forest fires in Alaska and Canada transported into the region, and 70% is attributed to the urban emissions of mainly New York and Boston. On some days the forest fire emissions were mixed down to the surface and dominated the CO enhancement. The results compare well with the FLEXPART transport model, indicating that the total emissions during the measurement campaign for biomass burning might be about 22 Tg. The total U.S. anthropogenic CO sources used in FLEXPART are 25 Tg. FLEXPART model, using the U.S. EPA NEI-99 data, overpredicts the CO mixing ratio around Boston and New York in 2004 by about 50%.
[Holzinger1999] Holzinger, R., C. Warneke, A. Hansel, A. Jordan, W. Lindinger, D. H. Scharffe, G. Schade, and P. J. Crutzen, "Biomass burning as a source of formaldehyde, acetaldehyde, methanol, acetone, acetonitrile, and hydrogen cyanide", Geophysical Research Letters, vol. 26, no. 8: Wiley Online Library, pp. 1161–1164, 1999.
Link: http://onlinelibrary.wiley.com/doi/10.1029/1999GL900156/full
[Yuan2010] Yuan, B., Y. Liu, M. Shao, S. Lu, and D. G. Streets, "Biomass burning contributions to ambient VOCs species at a receptor site in the Pearl River Delta (PRD), China.", Environ Sci Technol, vol. 44, no. 12: State Joint Key Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing, 100871, China., pp. 4577–4582, Jun, 2010.
Link: http://dx.doi.org/10.1021/es1003389
Abstract
Ambient VOCs were measured by a proton transfer reaction-mass spectrometer (PTR-MS) at a receptor site in the Pearl River Delta (PRD) during October 19-November 18, 2008. Biomass burning plumes are identified by using acetonitrile as tracer, and enhancement ratios (ERs) of nine VOCs species relative to acetonitrile are obtained from linear regression analysis and the source-tracer-ratio method. Enhancement ratios determined by the two different methods show good agreement for most VOCs species. Biomass burning contributions are investigated by using the source-tracer-ratio method. Biomass burning contributed 9.5%-17.7% to mixing ratios of the nine VOCs. The estimated biomass burning contributions are compared with local emission inventories. Large discrepancies are observed between our results and the estimates in two emission inventories. Though biomass burning emissions in TRACE-P inventory agree well with our results, the VOCs speciation for aromatic compounds may be not appropriate for Guangdong.
[1587] Hörtnagl, L., I. Bamberger, M. Graus, T. M. Ruuskanen, R. Schnitzhofer, M. Müller, A. Hansel, and G. Wohlfahrt, "Biotic, abiotic and management controls on methanol exchange above a temperate mountain grassland.", J Geophys Res Biogeosci, vol. 116, Sep, 2011.
Link: http://dx.doi.org/10.1029/2011jg001641
Abstract
<p>Methanol (CH3OH) fluxes were quantified above a managed temperate mountain grassland in the Stubai Valley (Tyrol, Austria) during the growing seasons 2008 and 2009. Half-hourly methanol fluxes were calculated by means of the virtual disjunct eddy covariance (vDEC) method using 3-dimensional wind data from a sonic anemometer and methanol volume mixing ratios measured with a proton-transfer-reaction mass spectrometer (PTR-MS). During (undisturbed) mature and growing phases methanol fluxes exhibited a clear diurnal cycle with close-to-zero fluxes during nighttime and emissions, up to 10 nmol m(-2) s(-1), which followed the diurnal course of radiation and air temperature. Management events were found to represent the largest perturbations of methanol exchange at the studied grassland ecosystem: Peak emissions of 144.5 nmol m(-2) s(-1) were found during/after cutting of the meadow reflecting the wounding of the plant material and subsequent depletion of the leaf internal aqueous methanol pools. After the application of organic fertilizer, elevated methanol emissions of up to 26.7 nmol m(-2) s(-1) were observed, likely reflecting enhanced microbial activity associated with the applied manure. Simple and multiple linear regression analyses revealed air temperature and radiation as the dominant abiotic controls, jointly explaining 47 % and 70 % of the variability in half-hourly and daily methanol fluxes. In contrast to published leaf-level laboratory studies, the surface conductance and the daily change in the amount of green plant area, used as ecosystem-scale proxies for stomatal conductance and growth, respectively, were found to exert only minor biotic controls on methanol exchange.</p>
[Righettoni2012] Righettoni, M., A. Tricoli, S. Gass, A. Schmid, A. Amann, and S. E. Pratsinis, "Breath acetone monitoring by portable Si:WO3 gas sensors.", Anal Chim Acta, vol. 738: Particle Technology Laboratory, Department of Mechanical and Process Engineering ETH Zurich, CH-8092 Zurich, Switzerland., pp. 69–75, Aug, 2012.
Link: http://dx.doi.org/10.1016/j.aca.2012.06.002
Abstract
Breath analysis has the potential for early stage detection and monitoring of illnesses to drastically reduce the corresponding medical diagnostic costs and improve the quality of life of patients suffering from chronic illnesses. In particular, the detection of acetone in the human breath is promising for non-invasive diagnosis and painless monitoring of diabetes (no finger pricking). Here, a portable acetone sensor consisting of flame-deposited and in situ annealed, Si-doped epsilon-WO(3) nanostructured films was developed. The chamber volume was miniaturized while reaction-limited and transport-limited gas flow rates were identified and sensing temperatures were optimized resulting in a low detection limit of acetone (?20ppb) with short response (10-15s) and recovery times (35-70s). Furthermore, the sensor signal (response) was robust against variations of the exhaled breath flow rate facilitating application of these sensors at realistic relative humidities (80-90%) as in the human breath. The acetone content in the breath of test persons was monitored continuously and compared to that of state-of-the-art proton transfer reaction mass spectrometry (PTR-MS). Such portable devices can accurately track breath acetone concentration to become an alternative to more elaborate breath analysis techniques.
[Schwarz2009] Schwarz, K.., A.. Pizzini, B.. Arendacká, K.. Zerlauth, W.. Filipiak, A.. Schmid, A.. Dzien, S.. Neuner, M.. Lechleitner, S.. Scholl-Buergi, et al., "Breath acetone-aspects of normal physiology related to age and gender as determined in a PTR-MS study.", J Breath Res, vol. 3, no. 2: Department of Operative Medicine, Innsbruck Medical University, Anichstrasse 35, A-6020 Innsbruck, Austria. Breath Research Unit of the Austrian Academy of Sciences, Dammstrasse 22, A-6850 Dornbirn, Austria., pp. 027003, Jun, 2009.
Link: http://dx.doi.org/10.1088/1752-7155/3/2/027003
Abstract
The present study was performed to determine the variations of breath acetone concentrations with age, gender and body-mass index (BMI). Previous investigations were based on a relatively small cohort of subjects (see Turner et al 2006 Physiol. Meas. 27 321-37). Since exhaled breath analysis is affected by considerable variation, larger studies are needed to get reliable information about the correlation of concentrations of volatiles in breath when compared with age, gender and BMI. Mixed expiratory exhaled breath was sampled using Tedlar bags. The concentrations of a mass-to-charge ratio (m/z) of 59, attributed to acetone, were then determined using proton transfer reaction-mass spectrometry. Our cohort, consisting of 243 adult volunteers not suffering from diabetes, was divided into two groups: one that fasted overnight prior to sampling (215 volunteers) and the other without a dietary control (28 volunteers). In addition, we considered a group of 44 healthy children (5-11 years old).The fasted subjects' concentrations of acetone ranged from 177 ppb to 2441 ppb, with an overall geometric mean (GM) of 628 ppb; in the group without a dietary control, the subjects' concentrations ranged from 281 ppb to 1246 ppb with an overall GM of 544 ppb. We found no statistically significant shift between the distributions of acetone levels in the breath of males and females in the fasted group (the Wilcoxon-Mann-Whitney test yielded p = 0.0923, the medians being 652 ppb and 587 ppb). Similarly, there did not seem to be a difference between the acetone levels of males and females in the group without a dietary control. Aging was associated with a slight increase of acetone in the fasted females; in males the increase was not statistically significant. Compared with the adults (a merged group), our group of children (5-11 years old) showed lower concentrations of acetone (p < 0.001), with a median of 263 ppb. No correlation was found between the acetone levels and BMI in adults. Our results extend those of Turner et al's (2006 Physiol. Meas. 27 321-37), who analyzed the breath of 30 volunteers (without a dietary control) by selected ion flow tube-mass spectrometry. They reported a positive correlation with age (but without statistical significance in their cohort, with p = 0.82 for males and p = 0.45 for females), and, unlike us, arrived at a p-value of 0.02 for the separation of males and females with respect to acetone concentrations. Our median acetone concentration for children (5-11 years) coincides with the median acetone concentration of young adults (17-19 years) reported by Spanel et al (2007 J. Breath Res. 1 026001).
[Herbig2011] Herbig, J.., M.. Seger, I.. Kohl, K.. Winkler, H.. Jamnig, A.. Zabernigg, C.. Baumgartner, and A.. Hansel, "Breath Analysis with PTR-MS: More breath markers for lung cancer", 5th International PTR-MS Conference on Proton Transfer Reaction Mass Spectrometry and Its Applications, pp. 31-33, 2011.
Link: http://www.ionicon.com/sites/default/files/uploads/doc/contributions_ptr_ms_Conference_5.pdf
Abstract
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.
[Mair2011] Mair, V.., J.. Dunkl, A.. Hansel, and I.. Kohl, "Breath gas analysis by PTR-TOF-MS in a clinical setting", 5th International PTR-MS Conference on Proton Transfer Reaction Mass Spectrometry and Its Applications, pp. 231, 2011.
Link: http://www.ionicon.com/sites/default/files/uploads/doc/contributions_ptr_ms_Conference_5.pdf
Abstract
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.
[Mayr2003b] Mayr, D., T. Maerk, W. Lindinger, H. Brevard, and C. Yeretzian, "Breath-by-breath analysis of banana aroma by proton transfer reaction mass spectrometry", International Journal of Mass Spectrometry, vol. 223: Elsevier, pp. 743–756, 2003.
Link: http://www.sciencedirect.com/science/article/pii/S1387380602009673
Abstract
We report on the in vivo breath-by-breath analysis of volatiles released in the mouth during eating of ripe and unripe banana. The air exhaled through the nose, nosespace (NS), is directly introduced into a proton transfer reaction mass spectrometer and the time-intensity profiles of a series of volatiles are monitored on-line. These include isopentyl and isobutyl acetate, two characteristic odour compounds of ripe banana, and 2E-hexenal and hexanal, compounds typical of unripe banana. Comparing the NS with the headspace (HS) profile, two differences are outlined. First, NS concentrations of some compounds are increased, compared to the HS, while others are decreased. This indicates that the in-mouth situation has characteristics of its own—mastication, mixing/dilution with saliva, temperature and pH—which modify the aroma relative to an HS aroma. Second, we discuss the temporal evolution of the NS. While 2E-hexenal and hexanal steadily increase in the NS during mastication of unripe banana, no such evolution is observed in volatile organic compounds (VOCs) while eating ripe banana. Furthermore, ripe banana shows high VOC concentrations in the swallow breath in contrast to unripe banana.
[Herbig2008] Herbig, J., T. Titzmann, J. Beauchamp, I. Kohl, and A. Hansel, "Buffered end-tidal (BET) sampling-a novel method for real-time breath-gas analysis.", J Breath Res, vol. 2, no. 3: Ionimed Analytik GmbH, Technikerstrasse 21a, A-6020 Innsbruck, Austria., pp. 037008, Sep, 2008.
Link: http://iopscience.iop.org/1752-7163/2/3/037008/
Abstract
We present a novel method for real-time breath-gas analysis using mass-spectrometric techniques: buffered end-tidal (BET) on-line sampling. BET has several advantages over conventional direct on-line sampling where the subject inhales and exhales through a sampling tube. In our approach, a single exhalation is administered through a tailored tube in which the end-tidal fraction of the breath-gas sample is buffered. This increases sampling time by an order of magnitude to several seconds, improving signal quality and reducing the total measurement time per test subject. Furthermore, only one exhalation per minute is required for sampling and the test subject can otherwise maintain a normal breathing pattern, thereby reducing the risk of hyperventilation. To validate our new BET sampling method we conducted comparative measurements with direct on-line sampling using proton-transfer-reaction mass spectrometry. We find excellent agreement in measured acetone and acetonitrile concentrations. High variability observed in breath-by-breath isoprene concentrations is attributed to differences in exhalation depth and influences of hyperventilation on end-tidal concentrations.
[VanRuth2008] Van Ruth, SM., A. Koot, W. Akkermans, N. Araghipour, M. Rozijn, M. Baltussen, A. Wisthaler, TD. Märk, and R. Frankhuizen, "Butter and butter oil classification by PTR-MS", European Food Research and Technology, vol. 227, no. 1: Springer, pp. 307–317, 2008.
Link: http://link.springer.com/article/10.1007/s00217-007-0724-7
Abstract
The potential of proton transfer reaction mass spectrometry (PTR-MS) as a tool for classification of milk fats was evaluated in relation to quality and authentication issues. Butters and butter oils were subjected to heat and off-flavouring treatments in order to create sensorially defective samples. The effect of the treatments was evaluated by means of PTR-MS analysis, sensory analysis and classical chemical analysis. Subsequently, partial least square-discriminant analysis models (PLS-DA) were fitted to predict the matrix (butter/butter oil) and the sensory grades of the samples from their PTR-MS data. Using a 10-fold cross-validation scheme, 84% of the samples were successfully classified into butter and butter oil classes. Regarding sensory quality, 89% of the samples were correctly classified. As the milk fats were fairly successfully classified by the combination of PTR-MS and PLS-DA, this combination seems a promising approach with potential applications in quality control and control of regulations.
[Bamberger2010] Bamberger, I., L. Hörtnagl, R. Schnitzhofer, M. Graus, TM. Ruuskanen, M. Müller, J. Dunkl, G. Wohlfahrt, and A. Hansel, "BVOC fluxes above mountain grassland", Biogeosciences, vol. 7, no. 5: Copernicus GmbH, pp. 1413–1424, 2010.
Link: http://www.biogeosciences.net/7/1413/2010/bg-7-1413-2010.pdf
[1585] Bamberger, I.., L.. Hortnagl, R.. Schnitzhofer, M.. Graus, T.. M. Ruuskanen, M.. Muller, J.. Dunkl, G.. Wohlfahrt, and A.. Hansel, "BVOC fluxes above mountain grassland.", Biogeosciences, vol. 7, May, 2010.
Link: http://www.biogeosciences.net/7/1413/2010/bg-7-1413-2010.html
Abstract
<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>
[Karl2013] Karl, T., A. Hansel, L. Cappellin, L. Kaser, I. Herdlinger-Blatt, and W. Jud, "BVOC measurements based on NO+ ionization", CONFERENCE SERIES, pp. 84, 2013.
Link: http://www.ionicon.com/sites/default/files/uploads/doc/contributions_ptr_ms_Conference_6.pdf
C
[Cooper2004] Cooper, OR., C. Forster, D. Parrish, M. Trainer, E. Dunlea, T. Ryerson, G. Huebler, F. Fehsenfeld, D. Nicks, J. Holloway, et al., "A case study of transpacific warm conveyor belt transport: Influence of merging airstreams on trace gas import to North America", Journal of geophysical research, vol. 109, no. D23: American Geophysical Union, pp. D23S08, 2004.
Link: http://www.agu.org/pubs/crossref/2004/2003JD003624.shtml
Abstract
The warm conveyor belt (WCB), the major cloud-forming airstream of midlatitude cyclones, is the primary mechanism for rapidly transporting air pollution from one continent to another. However, relatively little has been written on WCB transport across the North Pacific Ocean. To address this important intercontinental transport route, this study describes the life cycle of a WCB associated with the export of a highly polluted air mass from Asia to North America. This event was sampled using in situ measurements from an aircraft platform flying above the North American West Coast during the 2002 Intercontinental Transport and Chemical Transformation (ITCT 2K2) experiment on 5 May. Satellite imagery, trajectory ensembles, in situ measurements, and animations are used to illustrate the formation of the WCB near eastern Asia, its entrainment of polluted air masses, its transport path across the Pacific, and its decay above the eastern North Pacific Ocean and western North America. A major finding is that a WCB can entrain air from a variety of source regions and not just the atmospheric boundary layer. We estimate that 8% of the WCB's mass originated in the stratosphere and 44% passed through the lower troposphere, of which two thirds passed through the lower troposphere above the populated regions of eastern Asia. The remaining 48% traveled entirely within the middle and upper troposphere over the previous 5.5 days. Interestingly, an estimated 18% of the WCB's mass was entrained from an upwind and decaying WCB via a newly discovered but apparently common transport mechanism. Only 9% of the WCB's mass subsequently passed through the lower troposphere of the United States, with the remainder passing over North America in the middle and upper troposphere.
[vonDahl2006] von Dahl}, C. C. {, M. Haevecker, R. Schloegl, and I. T. Baldwin, "Caterpillar-elicited methanol emission: a new signal in plant-herbivore interactions?", Plant J, vol. 46, no. 6: Department of Molecular Ecology, Max Planck Institute for Chemical Ecology, Beutenberg Campus, Hans-Knoell-Strasse 8, 07745 Jena, Germany., pp. 948–960, Jun, 2006.
Link: http://dx.doi.org/10.1111/j.1365-313X.2006.02760.x
Abstract
Plants release into the atmosphere large quantities of volatile organic compounds (VOCs), of which methanol (MeOH), a putative waste product, is the second most abundant. Using online proton-transfer-reaction mass spectrometry (PTR-MS), we demonstrate that when Manduca sexta larvae attack Nicotiana attenuata plants, the wound-induced release of MeOH dramatically increases. The sustained MeOH emission 24 h after herbivore feeding is already substantially greater than the release of the well-characterized green-leaf VOC E-2-hexenal. Herbivore attack and treatment of puncture wounds with larval oral secretions (OS) increased the transcript accumulation and activity of leaf pectin methylesterases (PMEs), and decreased the degree of pectin methylation, as determined by (1)H-NMR; therefore, we propose that the released MeOH originates from the activation of PMEs by herbivore attack. The herbivore- and OS-elicited MeOH results not from the activity of previously characterized elicitors in OS but from a pH shift at the wound site when larval OS (pH 8.5-9.5) are introduced into the wounds during feeding. Applying MeOH to plants in quantities that mimic the herbivory-elicited release decreases the activity of the potent plant defense proteins trypsin proteinase inhibitors (TPI), and increases the performance of the attacking larvae. The pH of lepidopteran larvae regurgitants is commonly very high, and the MeOH released during feeding that is elicited by the pH change at the wound site functions as a quantitative signal that influences the outcome of the plant-herbivore interaction.
[Penuelas2005] Penuelas, J., I. Filella, C. Stefanescu, and J. Llusià, "Caterpillars of Euphydryas aurinia (Lepidoptera: Nymphalidae) feeding on Succisa pratensis leaves induce large foliar emissions of methanol.", New Phytol, vol. 167, no. 3: Unitat Ecofisiologia CSIC-CREAF CREAF, Edifici C, Universitat Autónoma de Barcelona, E-08193 Bellaterra, Barcelona, Spain. josep.penuelas@uab.es, pp. 851–857, Sep, 2005.
Link: http://dx.doi.org/10.1111/j.1469-8137.2005.01459.x
Abstract
A major new discovery made in the last decade is that plants commonly emit large amounts and varieties of volatiles after damage inflicted by herbivores, and not merely from the site of injury. However, analytical methods for measuring herbivore-induced volatiles do not usually monitor the whole range of these compounds and are complicated by the transient nature of their formation and by their chemical instability. Here we present the results of using a fast and highly sensitive proton transfer reaction-mass spectrometry (PTR-MS) technique that allows simultaneous on-line monitoring of leaf volatiles in the pptv (pmol mol(-1)) range. The resulting on-line mass scans revealed that Euphydryas aurinia caterpillars feeding on Succisa pratensis leaves induced emissions of huge amounts of methanol–a biogeochemically active compound and a significant component of the volatile organic carbon found in the atmosphere–and other immediate, late and systemic volatile blends (including monoterpenes, sesquiterpenes and lipoxygenase-derived volatile compounds). In addition to influencing neighboring plants, as well as herbivores and their predators and parasitoids, these large emissions might affect atmospheric chemistry and physics if they are found to be generalized in other plant species.
[Kohl2013] Kohl, I., J. Herbig, J. Dunkl, A. Hansel, M. Daniaux, and M. Hubalek, "Chapter 6 - Smokers Breath as Seen by Proton-Transfer-Reaction Time-of-Flight Mass Spectrometry (PTR-TOF-MS)", Volatile Biomarkers, Boston, Elsevier, pp. 89 - 116, 2013.
Link: http://www.sciencedirect.com/science/article/pii/B9780444626134000064
Abstract
Abstract Proton-transfer-reaction time-of-flight mass spectrometry has been employed in a 12&#xa0;months breath gas analysis study to describe the breath composition of 19 cigarette smoking and 53 non-smoking women. The most prevalent constituents were acetone (1.8&#xa0;ppmv), methanol (310&#xa0;ppbv), isoprene (280&#xa0;ppbv), ethanol (130&#xa0;ppbv), acetaldehyde (90&#xa0;ppbv) and acetic acid (70&#xa0;ppbv). Smokers showed the largest signal increase in acetonitrile (ratio smoker/non-smoker 29), benzene (ratio 11), 2-methylfuran (ratio 8) and 2,5-dimethylfuran (ratio 7). Calibration gas measurements allowed the instruments performance regarding precision and accuracy of ion mass-to-charge, m/z, and concentration accuracy measurement to be assessed. The standard deviation of the concentration measurements was 14% or smaller (with the exception of ethanol) with no trend in this variation of sensitivity. The limit of detection (LOD) lay in the sub ppbv range, based on an integration time of 2&#xa0;s. The m/z accuracy was better than 0.0016 (or less than 29&#xa0;ppm of the ion mass) throughout the study. The standard deviation of the measured m/z was less than 0.0025 and the coefficient of variation was less than 29&#xa0;ppm. Keywords PTR-TOF-MS, Smokers’ breath, Breath volatile organic compounds, \{VOCs\}
[Heenan2009] Heenan, S. P., J-P. Dufour, N. Hamid, W. Harvey, and C. M. Delahunty, "Characterisation of fresh bread flavour: Relationships between sensory characteristics and volatile composition", Food Chemistry, vol. 116, no. 1: Elsevier, pp. 249–257, 2009.
Link: http://www.sciencedirect.com/science/article/pii/S0308814609002301
Abstract
The sensory properties and volatile composition of bread flavour were measured to allow improved understanding of perceived bread freshness. Twenty bread varieties consisting of specialty breads (n = 10) and commercial breads (n = 10) were evaluated by descriptive sensory analysis, and volatile composition of all breads was measured by proton transfer reaction mass spectrometry (PTR-MS). The specialty breads (n = 10) studied had been evaluated by consumers, and perceived freshness was known. All sensory attributes and 33 mass ions representative of the PTR-MS spectra significantly (p < 0.05) distinguished between the different breads. Partial least squares regression (PLSR) was used to model and predict sensory profiles as a function of volatile composition for all breads. In addition, a separate model that related volatile composition to known consumer freshness of the 10 specialty breads was created. For each model, accuracy was validated by comparing the differences between predicted and actual, sensory and freshness intensities.
[Beauchamp2010a] Beauchamp, J., J. Frasnelli, A. Buettner, M. Scheibe, A. Hansel, and T. Hummel, "Characterization of an olfactometer by proton-transfer-reaction mass spectrometry", Measurement Science and Technology, vol. 21, no. 2, pp. 025801, 2010.
Link: http://stacks.iop.org/0957-0233/21/i=2/a=025801
Abstract
The performance of a commercial olfactometer instrument, which produces odorant pulses of defined duration and concentration, was characterized using proton-transfer-reaction mass spectrometry (PTR-MS). Direct coupling of the PTR-MS instrument with the olfactometer enabled on-line evaluation of the rapidly delivered aroma pulses. Tests were made with a selection of four odorous compounds: hydrogen sulfide, 2,3-butanedione, ethyl butanoate and ethyl hexanoate. Odour concentrations and stimulus durations for these compounds were monitored directly at the olfactometer delivery port via the respective PTR-MS signals. The performance of the olfactometer was found to be dependent on pulse duration. A decrease over time in maximum intensity for identical pulses over an extended duration showed headspace concentration depletions for compounds sourced from a water solution, indicative of gas/liquid partitioning. Such changes were not present using odours sourced from a cylinder or, presumably, when using liquid odours at neat concentrations. In conclusion, while an olfactometer provides stimuli with good reproducibility, the concept is subject to certain limitations that must be appreciated by the experimenter for accurate application of this technique.
[1566] Stockwell, C.. E., P.. R. Veres, J.. Williams, and R.. J. Yokelson, "Characterization of biomass burning smoke from cooking fires, peat, crop residue and other fuels with high resolution proton-transfer-reaction time-of-flight mass spectrometry", Atmospheric Chemistry and Physics Discussions, vol. 14, pp. 22163–22216, 2014.
Link: http://dx.doi.org/10.5194/acpd-14-22163-2014
Abstract
<p>We deployed a high-resolution proton-transfer-reaction time-of-flight mass spectrom-eter (PTR-TOF-MS) to measure biomass burning emissions from peat, crop-residue, cooking fires, and many other fire types during the fourth Fire Lab at Missoula Experi-ment (FLAME-4) laboratory campaign. A combination of gas standards calibrations and 5 composition sensitive, mass dependent calibration curves were applied to quantify gas-phase non-methane organic compounds (NMOCs) observed in the complex mixture of fire emissions. We used several approaches to assign best identities to most major &quot;exact masses&quot; including many high molecular mass species. Using these methods ap-proximately 80&ndash;96 % of the total NMOC mass detected by PTR-TOF-MS and FTIR was 10 positively or tentatively identified for major fuel types. We report data for many rarely measured or previously unmeasured emissions in several compound classes including aromatic hydrocarbons, phenolic compounds, and furans; many of which are suspected secondary organic aerosol precursors. A large set of new emission factors (EFs) for a range of globally significant biomass fuels is presented. Measurements show that 15 oxygenated NMOCs accounted for the largest fraction of emissions of all compound classes. In a brief study of various traditional and advanced cooking methods, the EFs for these emissions groups were greatest for open 3-stone cooking in comparison to their more advanced counterparts. Several little-studied nitrogen-containing organic compounds were detected from many fuel types that together accounted for 0.1&ndash;8.7 % 20 of the fuel nitrogen and some may play a role in new particle formation.</p>
[Guazzotti2003] Guazzotti, SA., DT. Suess, KR. Coffee, PK. Quinn, TS. Bates, A. Wisthaler, A. Hansel, WP. Ball, RR. Dickerson, C. Neusüß, et al., "Characterization of carbonaceous aerosols outflow from India and Arabia: Biomass/biofuel burning and fossil fuel combustion", Journal of geophysical research, vol. 108, no. D15: American Geophysical Union, pp. 4485, 2003.
Link: http://onlinelibrary.wiley.com/doi/10.1029/2002JD003277/abstract
Abstract
A major objective of the Indian Ocean Experiment (INDOEX) involves the characterization of the extent and chemical composition of pollution outflow from the Indian Subcontinent during the winter monsoon. During this season, low-level flow from the continent transports pollutants over the Indian Ocean toward the Intertropical Convergence Zone (ITCZ). Traditional standardized aerosol particle chemical analysis, together with real-time single particle and fast-response gas-phase measurements provided characterization of the sampled aerosol chemical properties. The gas- and particle-phase chemical compositions of encountered air parcels changed according to their geographic origin, which was traced by back trajectory analysis. The temporal evolutions of acetonitrile, a long-lived specific tracer for biomass/biofuel burning, number concentration of submicrometer carbon-containing particles with potassium (indicative of combustion sources), and mass concentration of submicrometer non-sea-salt (nss) potassium are compared. High correlation coefficients (0.84 < r2 < 0.92) are determined for these comparisons indicating that most likely the majority of the species evolve from the same, related, or proximate sources. Aerosol and trace gas measurements provide evidence that emissions from fossil fuel and biomass/biofuel burning are subject to long-range transport, thereby contributing to anthropogenic pollution even in areas downwind of South Asia. Specifically, high concentrations of submicrometer nss potassium, carbon-containing particles with potassium, and acetonitrile are observed in air masses advected from the Indian subcontinent, indicating a strong impact of biomass/biofuel burning in India during the sampling periods (74 (±9)% biomass/biofuel contribution to submicrometer carbonaceous aerosol). In contrast, lower values for these same species were measured in air masses from the Arabian Peninsula, where dominance of fossil fuel combustion is suggested by results from single-particle analysis and supported by results from gas-phase measurements (63 (±9))% fossil fuel contribution to submicrometer carbonaceous aerosol). Results presented here demonstrate the importance of simultaneous, detailed gas- and particle-phase measurements of related species when evaluating possible source contributions to aerosols in different regions of the world.
[1717] Klein, F., S. M. Platt, N. J. Farren, A. Detournay, E. A. Bruns, C. Bozzetti, K. R. Daellenbach, D. Kilic, N. K. Kumar, S. M. Pieber, et al., "Characterization of Gas-Phase Organics Using Proton Transfer Reaction Time-of-Flight Mass Spectrometry: Cooking Emissions.", Environ Sci Technol, vol. 50, pp. 1243–1250, Feb, 2016.
Link: http://dx.doi.org/10.1021/acs.est.5b04618
Abstract
<p>Cooking processes produce gaseous and particle emissions that are potentially deleterious to human health. Using a highly controlled experimental setup involving a proton-transfer-reaction time-of-flight mass spectrometer (PTR-ToF-MS), we investigate the emission factors and the detailed chemical composition of gas phase emissions from a broad variety of cooking styles and techniques. A total of 95 experiments were conducted to characterize nonmethane organic gas (NMOG) emissions from boiling, charbroiling, shallow frying, and deep frying of various vegetables and meats, as well as emissions from vegetable oils heated to different temperatures. Emissions from boiling vegetables are dominated by methanol. Significant amounts of dimethyl sulfide are emitted from cruciferous vegetables. Emissions from shallow frying, deep frying and charbroiling are dominated by aldehydes of differing relative composition depending on the oil used. We show that the emission factors of some aldehydes are particularly large which may result in considerable negative impacts on human health in indoor environments. The suitability of some of the aldehydes as tracers for the identification of cooking emissions in ambient air is discussed.</p>
[1668] Sekimoto, K., S. Inomata, H. Tanimoto, A. Fushimi, Y. Fujitani, K. Sato, and H. Yamada, "Characterization of nitromethane emission from automotive exhaust", Atmospheric Environment, vol. 81, pp. 523–531, Dec, 2013.
Link: http://dx.doi.org/10.1016/j.atmosenv.2013.09.031
Abstract
<p>We carried out time-resolved experiments using a proton-transfer-reaction mass spectrometer and a chassis dynamometer to characterize nitromethane emission from automotive exhaust. We performed experiments under both cold-start and hot-start conditions, and determined the dependence of nitromethane emission on vehicle velocity and acceleration/deceleration as well as the effect of various types of exhaust-gas treatment system. We found that nitromethane emission was much lower from a gasoline car than from diesel trucks, probably due to the reduction function of the three-way catalyst of the gasoline car. Diesel trucks without a NOx reduction catalyst using hydrocarbons produced high emissions of nitromethane, with emission factors generally increasing with increasing acceleration at low vehicle velocities.</p>
[Zavala2006] Zavala, M., SC. Herndon, RS. Slott, EJ. Dunlea, LC. Marr, JH. Shorter, M. Zahniser, WB. Knighton, TM. Rogers, CE. Kolb, et al., "Characterization of on-road vehicle emissions in the Mexico City Metropolitan Area using a mobile laboratory in chase and fleet average measurement modes during the MCMA-2003 field campaign", Atmospheric Chemistry and Physics, vol. 6, no. 12: Copernicus GmbH, pp. 5129–5142, 2006.
Link: http://www.atmos-chem-phys.net/6/5129/2006/acp-6-5129-2006.html
Abstract
A mobile laboratory was used to measure on-road vehicle emission ratios during the MCMA-2003 field campaign held during the spring of 2003 in the Mexico City Metropolitan Area (MCMA). The measured emission ratios represent a sample of emissions of in-use vehicles under real world driving conditions for the MCMA. From the relative amounts of NOx and selected VOC's sampled, the results indicate that the technique is capable of differentiating among vehicle categories and fuel type in real world driving conditions. Emission ratios for NOx, NOy, NH3, H2CO, CH3CHO, and other selected volatile organic compounds (VOCs) are presented for chase sampled vehicles in the form of frequency distributions as well as estimates for the fleet averaged emissions. Our measurements of emission ratios for both CNG and gasoline powered "colectivos" (public transportation buses that are intensively used in the MCMA) indicate that – in a mole per mole basis – have significantly larger NOx and aldehydes emissions ratios as compared to other sampled vehicles in the MCMA. Similarly, ratios of selected VOCs and NOy showed a strong dependence on traffic mode. These results are compared with the vehicle emissions inventory for the MCMA, other vehicle emissions measurements in the MCMA, and measurements of on-road emissions in U.S. cities. We estimate NOx emissions as 100 600±29 200 metric tons per year for light duty gasoline vehicles in the MCMA for 2003. According to these results, annual NOx emissions estimated in the emissions inventory for this category are within the range of our estimated NOx annual emissions. Our estimates for motor vehicle emissions of benzene, toluene, formaldehyde, and acetaldehyde in the MCMA indicate these species are present in concentrations higher than previously reported. The high motor vehicle aldehyde emissions may have an impact on the photochemistry of urban areas.

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Selected PTR-MS related Reviews

F. Biasioli, C. Yeretzian, F. Gasperi, T. D. Märk: PTR-MS monitoring of VOCs and BVOCs in food science and technology, Trends in Analytical Chemistry 30 (7) (2011).
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J. de Gouw, C. Warneke, T. Karl, G. Eerdekens, C. van der Veen, R. Fall: Measurement of Volatile Organic Compounds in the Earth's Atmosphere using Proton-Transfer-Reaction Mass Spectrometry. Mass Spectrometry Reviews, 26 (2007), 223-257.
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W. Lindinger, A. Hansel, A. Jordan: Proton-transfer-reaction mass spectrometry (PTR–MS): on-line monitoring of volatile organic compounds at pptv levels, Chem. Soc. Rev. 27 (1998), 347-375.
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Lists with PTR-MS relevant publications of the University of Innsbruck can be found here: Atmospheric and indoor air chemistry, IMR, Environmental Physics and Nano-Bio-Physics

 

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