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Scientific Articles - PTR-MS Bibliography

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Found 767 results
Title [ Year(Asc)]
2014
[1561] Beauchamp, J., E. Zardin, P. Silcock, and P. J. Bremer, "Monitoring photooxidation-induced dynamic changes in the volatile composition of extended shelf life bovine milk by PTR-{MS}", Journal of Mass Spectrometry, vol. 49, pp. 952–958, Sep, 2014.
Link: http://dx.doi.org/10.1002/jms.3430
Abstract
<p>Exposure of milk to light leads to photooxidation and the development of off-flavours. To follow these reactions, semi-skimmed (1.5% fat) and whole (3.8% fat) extended shelf life (ESL) bovine milk samples were exposed to fluorescent light for up to 20 h at room temperature, and the volatiles in the samples&#39; headspace were measured in real time using proton-transfer-reaction mass spectrometry (PTR-MS). Compounds tentatively identified as methanethiol, acetone/propanal, pentanal/octanal/nonanal/1-octen-3-ol, hexanal, diacetyl, dimethyl disulphide, heptanal and benzaldehyde displayed dynamic release profiles relating to the changes occurring in milk upon exposure to light. Copyright &copy; 2014 John Wiley &amp; Sons, Ltd.</p>
[1722] "Omics in Soil Science", : Caister Academic Press, 2014.
Link: http://www.horizonpress.com/omics
Abstract
<p>Soil is a unique biological system with an abundant microflora and a very high microbial diversity capable of performing multiple key ecosystem functions. The detection of genes in soil has improved the knowledge of unculturable microorganisms and led to a greater understanding of potential soil metabolic pathways. Further advances in understanding soil functionality are being realised by harnessing omics technologies such as metagenomics, metatranscriptomics, proteomics and volatilomics. The next challenge of systems biology and functional genomics is to integrate the information from omic approaches to give a more complete picture of soil as a biological system. This volume presents the state-of-the-art of omic applications in soil science, a field that is advancing rapidly on many fronts. Distinguished authors describe the application of metagenomics, metatranscriptomics and proteomics to soil science. In particular the book covers the current and emerging omics techniques and the contribution of these approaches to a better assessment of soil functionality. The authors also explore the specific problems encountered in the application of various omics technologies to soil science and the future research requirements necessary to overcome the current limitations in this area. Topics covered include soil functional genomics, soil metagenomics, soil microbial ecology, soil metatranscriptomics, soil proteomics, soil volatilomics and soil proteogenomics. Omics techniques are also discussed in comparison with classical techniques. This book is both a practical guide and a recommended reference volume for all soil scientists.</p>
[1597] Szymczak, W., J. Rozman, V. Höllriegl, M. Kistler, S. Keller, D. Peters, M. Kneipp, H. Schulz, C. Hoeschen, M. Klingenspor, et al., "Online breath gas analysis in unrestrained mice by hs-PTR-MS.", Mamm Genome, vol. 25, pp. 129–140, Apr, 2014.
Link: http://dx.doi.org/10.1007/s00335-013-9493-8
Abstract
<p>The phenotyping of genetic mouse models for human disorders may greatly benefit from breath gas analysis as a noninvasive tool to identify metabolic alterations in mice. Phenotyping screens such as the German Mouse Clinic demand investigations in unrestrained mice. Therefore, we adapted a breath screen in which exhaled volatile organic compounds (VOCs) were online monitored by proton transfer reaction mass spectrometry (hs-PTR-MS). The source strength of VOCs was derived from the dynamics in the accumulation profile of exhaled VOCs of a single mouse in a respirometry chamber. A careful survey of the accumulation revealed alterations in the source strength due to confounders, e.g., urine and feces. Moreover changes in the source strength of humidity were triggered by changes in locomotor behavior as mice showed a typical behavioral pattern from activity to settling down in the course of subsequent accumulation profiles. We demonstrated that metabolic changes caused by a dietary intervention, e.g., after feeding a high-fat diet (HFD) a sample of 14 male mice, still resulted in a statistically significant shift in the source strength of exhaled VOCs. Applying a normalization which was derived from the distribution of the source strength of humidity and accounted for varying locomotor behaviors improved the shift. Hence, breath gas analysis may provide a noninvasive, fast access to monitor the metabolic adaptation of a mouse to alterations in energy balance due to overfeeding or fasting and dietary macronutrient composition as well as a high potential for systemic phenotyping of mouse mutants, intervention studies, and drug testing in mice.</p>
[1703] Timkovsky, J.., P.. Gankema, R.. Pierik, and R.. Holzinger, "A plant chamber system with downstream reaction chamber to study the effects of pollution on biogenic emissions.", Environ Sci Process Impacts, vol. 16, pp. 2301–2312, 2014.
Link: http://dx.doi.org/10.1039/c4em00214h
Abstract
<p>A system of two plant chambers and a downstream reaction chamber has been set up to investigate the emission of biogenic volatile organic compounds (BVOCs) and possible effects of pollutants such as ozone. The system can be used to compare BVOC emissions from two sets of differently treated plants, or to study the photochemistry of real plant emissions under polluted conditions without exposing the plants to pollutants. The main analytical tool is a proton-transfer-reaction time-of-flight mass spectrometer (PTR-TOF-MS) which allows online monitoring of biogenic emissions and chemical degradation products. The identification of BVOCs and their oxidation products is aided by cryogenic trapping and subsequent in situ gas chromatographic analysis.</p>
[1643] Mochalski, P., K. Unterkofler, P. Spanel, D. Smith, and A. Amann, "Product ion distributions for the reactions of NO(+) with some physiologically significant aldehydes obtained using a SRI-TOF-MS instrument.", Int J Mass Spectrom, vol. 363, pp. 23–31, Apr, 2014.
Link: http://dx.doi.org/10.1016/j.ijms.2014.02.016
Abstract
<p>Product ion distributions for the reactions of NO(+) with 22 aldehydes involved in human physiology have been determined under the prevailing conditions of a selective reagent ionization time of flight mass spectrometry (SRI-TOF-MS) at an E/N in the flow/drift tube reactor of 130 Td. The chosen aldehydes were fourteen alkanals (the C2-C11 n-alkanals, 2-methyl propanal, 2-methyl butanal, 3-methyl butanal, and 2-ethyl hexanal), six alkenals (2-propenal, 2-methyl 2-propenal, 2-butenal, 3-methyl 2-butenal, 2-methyl 2-butenal, and 2-undecenal), benzaldehyde, and furfural. The product ion fragmentations patterns were determined for both dry air and humid air (3.5% absolute humidity) used as the matrix buffer/carrier gas in the drift tube of the SRI-TOF-MS instrument. Hydride ion transfer was seen to be a common ionization mechanism in all these aldehydes, thus generating (M-H)(+) ions. Small fractions of the adduct ion, NO(+)M, were also seen for some of the unsaturated alkenals, in particular 2-undecenal, and heterocyclic furfural for which the major reactive channel was non-dissociative charge transfer generating the M(+) parent ion. Almost all of the reactions resulted in partial fragmentation of the aldehyde molecules generating hydrocarbon ions; specifically, the alkanal reactions resulted in multiple product ions, whereas, the alkenals reactions produced only two or three product ions, dissociation of the nascent excited product ion occurring preferentially at the 2-position. The findings of this study are of particular importance for data interpretation in studies of aldehydes reactions employing SRI-TOF-MS in the NO(+) mode.</p>
[1551] Brilli, F., B. Gioli, P. Ciccioli, D. Zona, F. Loreto, I. A. Janssens, and R. Ceulemans, "Proton Transfer Reaction Time-of-Flight Mass Spectrometric (PTR-TOF-MS) determination of volatile organic compounds (VOCs) emitted from a biomass fire developed under stable nocturnal conditions", Atmospheric Environment, vol. 97, pp. 54 - 67, 2014.
Link: http://www.sciencedirect.com/science/article/pii/S1352231014006013
Abstract
<p>Abstract Combustion of solid and liquid fuels is the largest source of potentially toxic volatile organic compounds (VOCs), which can strongly affect health and the physical and chemical properties of the atmosphere. Among combustion processes, biomass burning is one of the largest at global scale. We used a Proton Transfer Reaction &ldquo;Time-of-Flight&rdquo; Mass Spectrometer (PTR-TOF-MS), which couples high sensitivity with high mass resolution, for real-time detection of multiple \{VOCs\} emitted by burned hay and straw in a barn located near our measuring station. We detected 132 different organic ions directly attributable to \{VOCs\} emitted from the fire. Methanol, acetaldehyde, acetone, methyl vinyl ether (MVE), acetic acid and glycolaldehyde dominated the \{VOC\} mixture composition. The time-course of the 25 most abundant VOCs, representing &sim;85% of the whole mixture of VOCs, was associated with that of carbon monoxide (CO), carbon dioxide (CO2) and methane (CH4) emissions. The strong linear relationship between the concentrations of pyrogenic \{VOC\} and of a reference species (i.e. CO) allowed us to compile a list of emission ratios (ERs) and emission factors (EFs), but values of \{ER\} (and EF) were overestimated due to the limited mixing of the gases under the stable (non-turbulent) nocturnal conditions. In addition to the 25 most abundant VOCs, chemical formula and concentrations of the residual, less abundant \{VOCs\} in the emitted mixture were also estimated by PTR-TOF-MS. Furthermore, the evolution of the complex combustion process was described on the basis of the diverse types of pyrogenic gases recorded.</p>
[1533] Sulzer, P., E. Hartungen, G. Hanel, S. Feil, K. Winkler, P. Mutschlechner, S. Haidacher, R. Schottkowsky, D. Gunsch, H. Seehauser, et al., "A Proton Transfer Reaction-Quadrupole interface Time-Of-Flight Mass Spectrometer (PTR-QiTOF): High speed due to extreme sensitivity", International Journal of Mass Spectrometry, vol. 368, pp. 1-5, 2014.
Link: http://www.sciencedirect.com/science/article/pii/S1387380614001584
Abstract
<p>Here we introduce a new prototype of a Proton Transfer Reaction-Time-Of-Flight Mass Spectrometry (PTR-TOFMS) instrument. In contrast to commercially available PTR-TOFMS devices so far, which utilize a transfer lens system, the novel prototype is equipped with a quadrupole ion guide for the highly effective transfer of ions from the drift tube to the mass spectrometer; hence we call it PTR-QiTOF, whereas &ldquo;Qi&rdquo; stands for &ldquo;Quadrupole interface&rdquo;. This new interface greatly improves the TOF mass resolution because of favorable injection conditions. Depending on whether we optimize the PTR-QiTOF to maximum sensitivity or maximum mass resolution, we get about 6900 and 10,400 m/m mass resolution, respectively, already at m/z 149 (increasing with ascending masses). Furthermore, we increase the pressure in the drift tube from typically 2.2 mbar to 3.8 mbar and the drift tube voltage from 600V to 1000 V. We directly compare the sensitivities of a commercial state-of-the-art PTR-TOFMS instrument to this &ldquo;high pressure&rdquo; PTR-QiTOF prototype and find that these modifications lead to a gain on average by a factor of 25 in terms of sensitivity with a maximum of about 4700 cps/ppbv for dichlorobenzene atm/z 147 for the PTR-QiTOF. This is (to our knowledge) the highest sensitivity ever reported for a PTR-MS instrument, regardless of the employed mass spectrometer. The increased sensitivity also has a very positive effect on the detection limit, which lies now at about 20 pptv with 100ms and 750 ppqv after 1 min integration time.Weprovide data on the linearity of the instrumental response over a concentration range of five orders of magnitude and evaluate the prototype&rsquo;s performance in a real-life test by analyzing the dynamic headspace of a minute amount of trinitrotoluene using only 2 s integration time.</p>
[1565] Makhoul, S., A. Romano, L. Cappellin, G. Spano, V. Capozzi, E. Benozzi, T. D. Märk, E. Aprea, F. Gasperi, H. El-Nakat, et al., "Proton-transfer-reaction mass spectrometry for the study of the production of volatile compounds by bakery yeast starters", Journal of Mass Spectrometry, vol. 49, pp. 850--859, Sep, 2014.
Link: http://dx.doi.org/10.1002/jms.3421
Abstract
<p>The aromatic impact of bakery yeast starters is currently receiving considerable attention. The flavor characteristics of the dough and the finished products are usually evaluated by gas chromatography and sensory analysis. The limit of both techniques resides in their low-throughput character. In the present work, proton-transfer-reaction mass spectrometry (PTR-MS), coupled to a time-of-flight mass analyzer, was employed, for the first time, to measure the volatile fractions of dough and bread, and to monitor Saccharomyces cerevisiae volatile production in a fermented food matrix. Leavening was performed on small-scale (1 g) dough samples inoculated with different commercial yeast strains. The leavened doughs were then baked, and volatile profiles were determined during leavening and after baking. The experimental setup included a multifunctional autosampler, which permitted the follow-up of the leavening process on a small scale with a typical throughput of 500 distinct data points in 16 h. The system allowed to pinpoint differences between starter yeast strains in terms of volatile emission kinetics, with repercussions on the final product (i.e. the corresponding micro-loaves). This work demonstrates the applicability of PTR-MS for the study of volatile organic compound production during bread-making, for the automated and online real-time monitoring of the leavening process, and for the characterization and selection of bakery yeast starters in view of their production of volatile compounds. Copyright &copy; 2014 John Wiley &amp; Sons, Ltd.</p>
[1609] Makhoul, S., A. Romano, L. Cappellin, G. Spano, V. Capozzi, E. Benozzi, T. D. Märk, E. Aprea, F. Gasperi, H. El-Nakat, et al., "Proton-transfer-reaction mass spectrometry for the study of the production of volatile compounds by bakery yeast starters.", J Mass Spectrom, vol. 49, pp. 850–859, Sep, 2014.
Link: http://dx.doi.org/10.1002/jms.3421
Abstract
<p>The aromatic impact of bakery yeast starters is currently receiving considerable attention. The flavor characteristics of the dough and the finished products are usually evaluated by gas chromatography and sensory analysis. The limit of both techniques resides in their low-throughput character. In the present work, proton-transfer-reaction mass spectrometry (PTR-MS), coupled to a time-of-flight mass analyzer, was employed, for the first time, to measure the volatile fractions of dough and bread, and to monitor Saccharomyces cerevisiae volatile production in a fermented food matrix. Leavening was performed on small-scale (1&thinsp;g) dough samples inoculated with different commercial yeast strains. The leavened doughs were then baked, and volatile profiles were determined during leavening and after baking. The experimental setup included a multifunctional autosampler, which permitted the follow-up of the leavening process on a small scale with a typical throughput of 500 distinct data points in 16&thinsp;h. The system allowed to pinpoint differences between starter yeast strains in terms of volatile emission kinetics, with repercussions on the final product (i.e. the corresponding micro-loaves). This work demonstrates the applicability of PTR-MS for the study of volatile organic compound production during bread-making, for the automated and online real-time monitoring of the leavening process, and for the characterization and selection of bakery yeast starters in view of their production of volatile compounds.</p>
[1704] Yener, S., A. Romano, L. Cappellin, T. D. Märk, J. {Sánchez Del Pulgar}, F. Gasperi, L. Navarini, and F. Biasioli, "PTR-ToF-MS characterisation of roasted coffees (C. arabica) from different geographic origins.", J Mass Spectrom, vol. 49, pp. 929–935, Sep, 2014.
Link: http://dx.doi.org/10.1002/jms.3455
Abstract
<p>Characterisation of coffees according to their origins is of utmost importance for commercial qualification. In this study, the aroma profiles of different batches of three monoorigin roasted Coffea arabica coffees (Brazil, Ethiopia and Guatemala) were analysed by Proton-Transfer-Reaction-Time of Flight-Mass Spectrometry (PTR-ToF-MS). The measurements were performed with the aid of a multipurpose autosampler. Unsupervised and supervised multivariate data analysis techniques were applied in order to visualise data and classify the coffees according to origin. Significant differences were found in volatile profiles of coffees. Principal component analysis allowed visualising a separation of the three coffees according to geographic origin and further partial least square regression-discriminant analysis classification showed completely correct predictions. Remarkably, the samples of one batch could be used as training set to predict geographic origin of the samples of the other batch, suggesting the possibility to predict further batches in coffee production by means of the same approach. Tentative identification of mass peaks aided characterisation of aroma fractions. Classification pinpointed some volatile compounds important for discrimination of coffees.</p>
[1606] Denzer, M. Y., S. Gailer, D. W. Kern, P. L Schumm, N. Thuerauf, J. Kornhuber, A. Buettner, and J. Beauchamp, "Quantitative Validation of the n-Butanol Sniffin' Sticks Threshold Pens.", Chemosens Percept, vol. 7, pp. 91–101, 2014.
Link: http://dx.doi.org/10.1007/s12078-014-9168-1
Abstract
<p>Odorant pens are used by medical practitioners and researchers to assess olfactory dysfunction. Despite their routine use, there are currently no data on the gas-phase odorant concentrations released from the pen tips or whether these concentrations scale linearly with the aqueous-phase concentrations inside the pens. The commercially available Sniffin&#39; Sticks odor threshold test containing n-butanol was chosen for evaluation. The gas-phase concentration of n-butanol at the tip of each pen was measured directly in a new set of pens via proton-transfer-reaction mass spectrometry (PTR-MS). Measurements were additionally made on the same pens after 6&nbsp;months and two older pen sets, namely a 3-year-old (used) and 4-year-old (new) set. Furthermore, application-related tests were made to determine the performance of the pens during routine use and under stress. These data demonstrate that the gas-phase n-butanol concentrations of the threshold pens are linear over the entire set, both for brand-new pens and 6&nbsp;months later; this reflects the expected performance that was previously only assumed. Furthermore, the application-simulation tests demonstrated a good performance of the pens when used according to their intended protocol. Measurements of the older pen sets suggest that storage conditions are more critical than usage for pen stability. The present findings confirm that the n-butanol odorant pens are an appropriate tool for threshold testing, provided they are stored and handled correctly.</p>
[1468] Luchner, M., T. Schmidberger, and G. Striedner, "Real-Time Approach", European Biopharmaceutical Review, vol. 1, pp. 52–55, 01/2014.
Link: http://edition.pagesuite-professional.co.uk/Launch.aspx?PBID=587773cf-29c4-46f2-9d9d-2f87bf178b5c
Abstract
<p>The complexity of using living cells as production system for modern biopharmaceuticals represents a major challenge in bioprocess design and control. Real-time access to relevant process variables is limited - however, proton transfer reaction mass spectrometers hold great potential to change this.</p>
[1523] Herbig, J.., R.. Gutmann, K.. Winkler, A.. Hansel, and G.. Sprachmann, "Real-Time Monitoring of Trace Gas Concentrations in Syngas", Oil Gas Sci. Technol. Rev. IFP Energies nouvelles, vol. 69, pp. 363–372, August, 2014.
Link: http://ogst.ifpenergiesnouvelles.fr/articles/ogst/abs/2014/02/ogst120243/ogst120243.html
Abstract
<p>EN: A Proton Transfer Reaction Mass Spectrometer (PTR-MS) was used for the analysis of syngas in an industrial Fischer-Tropsch process. A PTR-MS can detect a variety of volatile organic and inorganic compounds in real-time and with high sensitivity. Together with a multiplexer, this allows for online (real-time) monitoring of the trace contaminations at different stages of a Fischer-Tropsch process. Several volatile compounds, such as HCN, H2S, RSH, carbonyls, acids, alcohols and others have been measured in Syngas. This paper describes the setup to monitor syngas using PTR-MS and summarizes the result of this proof-of-principle project. FR: Un spectromètre de masse par réaction de transfert de protons (PTR-MS, Proton Transfer Reaction &ndash; Mass Spectrometer) a été utilisé pour l&rsquo;analyse de gaz de synthèse dans un procédé industriel Fischer-Tropsch. Un PTR-MS peut détecter une grande variété de composés organiques et inorganiques volatils en temps réel et avec une sensibilité élevée. Associé à un multiplexeur, il permet un suivi en ligne (en temps réel) des contaminants à l&rsquo;état de traces à différents stades d&rsquo;un procédé Fischer-Tropsch. Plusieurs composés volatils, tels que HCN, H2S, RSH, des carbonyles, des acides, des alcools et autres, ont été mesurés dans du gaz de synthèse. Cet article décrit la configuration pour le suivi du gaz de synthèse en utilisant le PTR-MS et résume le résultat de ce projet de preuve de concept.</p>
[1665] Yanagisawa, N., "Results of on-line measurement of organic compounds adsorbed on diesel exhaust particles by PTR-TOFMS", (Poster) 18th ETH Conference on Combustion Generated Nanoparticles, vol. 18, June, 2014.
Link: http://www.nanoparticles.ch/2014_ETH-NPC-18/Yanagisawa.pdf
Abstract
Organic compounds in particle-phase of diesel emission are of interest in view of particle nature and origin. In this work, particle‐phase organic compounds from a modern diesel engine were analyzed using on-line PTR‐TOFMS (Proton Transfer Reaction – Time of Flight Mass Spectrometer). To analyze particle-phase organic compounds, sampled exhaust was passed through a heating tube upstream of PTR-TOFMS. The results show that higher molecular weight compounds had higher portion in particle-phase and concentration changes corresponded to operating condition change of the engine.
[1521] Brilli, F., B. Gioli, D. Zona, E. Pallozzi, T. Zenone, G. Fratini, C. Calfapietra, F. Loreto, I. A. Janssens, and R. Ceulemans, "Simultaneous leaf- and ecosystem-level fluxes of volatile organic compounds from a poplar-based SRC plantation", Agricultural and Forest Meteorology, vol. 187, pp. 22–35, Apr, 2014.
Link: http://dx.doi.org/10.1016/j.agrformet.2013.11.006
Abstract
<p>Emission of carbon from ecosystems in the form of volatile organic compounds (VOC) represents a minorcomponent flux in the global carbon cycle that has a large impact on ground-level ozone, particle andaerosol formation and thus on air chemistry and quality. This study reports exchanges of CO2and VOCbetween a poplar-based short rotation coppice (SRC) plantation and the atmosphere, measured simul-taneously at two spatial scale, one at stand level and another at leaf level. The first technique combinedProton Transfer Reaction &ldquo;Time-of-Flight&rdquo; mass spectrometry (PTR&ndash;TOF&ndash;MS) with the eddy covariancemethod, to measure fluxes of a multitude of VOC. Abundant fluxes of isoprene, methanol and, to a lesserextent, fluxes of other oxygenated VOC such as formaldehyde, isoprene oxidation products (methyl vinylketone and methacrolein), methyl ethyl ketone, acetaldehyde, acetone and acetic acid, were measured.Under optimal environmental conditions, isoprene flux was mostly controlled by temperature and light.Differently, methanol flux underwent a combined enzymatic and stomatal control, together involvingenvironmental drivers such as vapour pressure deficit (VPD), temperature and light intensity. Moreoverfair weather condition favoured ozone deposition to the poplar plantation.The second technique involved trapping the VOCs emitted from leaves followed by gaschromatography-mass spectrometry (GC&ndash;MS) analysis. These leaf-level measurements showed thatemission of isoprene in adult leaves and of monoterpenes in juvenile leaves are widespread across poplargenotypes. Detection of isoprene oxidation products (iox) emission with leaf-level measurements con-firmed that a fraction of isoprene may be already oxidized within leaves, possibly when isoprene copeswith foliar reactive oxygen species (ROS) formed during warm and sunny days.</p>
[1723] Insam, H., "Soil volatile organic compounds as tracers for microbial activities in soils", Omics in Soil Science: Caister Academic Press, pp. 127–138, 2014.
Link: http://www.horizonpress.com/omics
[1759] Greenberg, J.. P., J.. Penuelas, A.. Guenther, R.. Seco, A.. Turnipseed, X.. Jiang, I.. Filella, M.. Estiarte, J.. Sardans, R.. Ogaya, et al., "A tethered-balloon PTRMS sampling approach for surveying of landscape-scale biogenic VOC fluxes", Atmospheric Measurement Techniques, vol. 7, pp. 2263–2271, Jul, 2014.
Link: http://dx.doi.org/10.5194/amt-7-2263-2014
Abstract
<p>To survey landscape-scale fluxes of biogenic gases, a 100 m Teflon tube was attached to a tethered balloon as a sampling inlet for a fast response Proton Transfer Reaction Mass Spectrometer (PTRMS). Along with meteorological instruments deployed on the tethered balloon and at 3 m and outputs from a regional weather model, these observations were used to estimate landscape scale biogenic volatile organic compound fluxes with two micrometeorological techniques: mixed layer variance and surface layer gradients. This highly mobile sampling system was deployed at four field sites near Barcelona to estimate landscape-scale BVOC emission factors in a relatively short period (3 weeks). The two micrometeorological techniques agreed within the uncertainty of the flux measurements at all four sites even though the locations had considerable heterogeneity in species distribution and complex terrain. The observed fluxes were significantly different than emissions predicted with an emission model using site-specific emission factors and land-cover characteristics. Considering the wide range in reported BVOC emission factors of VOCs for individual vegetation species (more than an order of magnitude), this flux estimation technique is useful for constraining BVOC emission factors used as model inputs.</p>
[1529] Platt, S.M.., I.E.. Haddad, S.M.. Pieber, R.-J.. Huang, A.A.. Zardini, M.. Clairotte, R.. Suarez-Bertoa, P.. Barmet, L.. Pfaffenberger, R.. Wolf, et al., "Two-stroke scooters are a dominant source of air pollution in many cities", Nature Communications, vol. 5, May, 2014.
Link: http://dx.doi.org/10.1038/ncomms4749
Abstract
<p>Fossil fuel-powered vehicles emit significant particulate matter, for example, black carbon and primary organic aerosol, and produce secondary organic aerosol. Here we quantify secondary organic aerosol production from two-stroke scooters. Cars and trucks, particularly diesel vehicles, are thought to be the main vehicular pollution sources. This needs re-thinking, as we show that elevated particulate matter levels can be a consequence of &lsquo;asymmetric pollution&rsquo; from two-stroke scooters, vehicles that constitute a small fraction of the fleet, but can dominate urban vehicular pollution through organic aerosol and aromatic emission factors up to thousands of times higher than from other vehicle classes. Further, we demonstrate that oxidation processes producing secondary organic aerosol from vehicle exhaust also form potentially toxic &lsquo;reactive oxygen species&rsquo;.</p>
[1562] Farneti, B., N. Busatto, I. Khomenko, L. Cappellin, S. Gutierrez, F. Spinelli, R. Velasco, F. Biasioli, G. Costa, and F. Costa, "Untargeted metabolomics investigation of volatile compounds involved in the development of apple superficial scald by PTR-ToF-MS", Metabolomics, Jul, 2014.
Link: http://dx.doi.org/10.1007/s11306-014-0696-0
Abstract
<p>The superficial scald is an important physiological disorder affecting apple fruit during postharvest storage. To date, the accumulation, and further oxidation, of α-farnesene was considered as the most probable cause for the development of this physiopathy. In order to perform a more broad investigation, a PTR-ToF&ndash;MS (proton transfer reaction&mdash;time of flight&mdash;mass spectrometry) was employed to monitor the volatile organic compounds (VOCs) production along with the progression of this disorder in fruit of &ldquo;Granny Smith&rdquo;, an apple variety known to be highly susceptible to scald. The untargeted metabolite investigation was performed on both skin and pulp, as well as comparing control versus treated tissues with 1-methylcyclopropene (1-MCP), an ethylene competitor widely used to prevent the development of this phenomenon. The rapid and non-destructive analysis of the VOC array carried out by PTR-ToF&ndash;MS identified three specific groups of metabolites in the skin, among which the 6-methyl-5-hepten-2-one (MHO) resulted significantly associated with the development of the superficial scald in apple. The results proposed in this work suggest the use of this novel equipment for an on-line monitoring of the VOCs released by the apple during the postharvest storage, as well as to use MHO as a possible biochemical marker for an early detection of the superficial scald symptoms.</p>
[1600] Kreuzwieser, J., U. Scheerer, J. Kruse, T. Burzlaff, A. Honsel, S. Alfarraj, P. Georgiev, JÖRG-PETER. SCHNITZLER, A. Ghirardo, I. Kreuzer, et al., "The Venus flytrap attracts insects by the release of volatile organic compounds.", J Exp Bot, vol. 65, pp. 755–766, Feb, 2014.
Link: http://dx.doi.org/10.1093/jxb/ert455
Abstract
<p>Does Dionaea muscipula, the Venus flytrap, use a particular mechanism to attract animal prey? This question was raised by Charles Darwin 140 years ago, but it remains unanswered. This study tested the hypothesis that Dionaea releases volatile organic compounds (VOCs) to allure prey insects. For this purpose, olfactory choice bioassays were performed to elucidate if Dionaea attracts Drosophila melanogaster. The VOCs emitted by the plant were further analysed by GC-MS and proton transfer reaction-mass spectrometry (PTR-MS). The bioassays documented that Drosophila was strongly attracted by the carnivorous plant. Over 60 VOCs, including terpenes, benzenoids, and aliphatics, were emitted by Dionaea, predominantly in the light. This work further tested whether attraction of animal prey is affected by the nutritional status of the plant. For this purpose, Dionaea plants were fed with insect biomass to improve plant N status. However, although such feeding altered the VOC emission pattern by reducing terpene release, the attraction of Drosophila was not affected. From these results it is concluded that Dionaea attracts insects on the basis of food smell mimicry because the scent released has strong similarity to the bouquet of fruits and plant flowers. Such a volatile blend is emitted to attract insects searching for food to visit the deadly capture organ of the Venus flytrap.</p>
[1619] Kumar, V.., and V.. Sinha, "VOC-OHM: A new technique for rapid measurements of ambient total OH reactivity and volatile organic compounds using a single proton transfer reaction mass spectrometer", International Journal of Mass Spectrometry, vol. 374, pp. 55–63, Dec, 2014.
Link: http://dx.doi.org/10.1016/j.ijms.2014.10.012
Abstract
Measurements of total hydroxyl radical (OH) reactivity and volatile organic compounds (VOC) are necessary for improving our understanding of reactive emissions and atmospheric oxidation in air pollution and atmospheric chemistry studies. Proton transfer reaction mass spectrometers (PTR-MS) can measure ambient VOCs and the total ambient OH reactivity. However, till date this has always required deployment of two PTR-MS instruments, wherein one instrument measures ambient VOCs and the other instrument measures the total OH reactivity using the comparative reactivity method (CRM). Due to material (e.g. power, space) or financial constraints, deploying two PTR-MS instruments is not always possible and yet it is desirable to quantify both VOCs and OH reactivity. Here, we present a novel hyphenated technique christened VOC-OHM (for Volatile Organic Compounds–OH reactivity Measurement) that enables rapid ambient measurements of both VOCs and total OH reactivity using a single PTR-MS. The technique can provide more specificity for identification of compounds using a PTR-QMS through an estimate of the rate coefficient of the major isobaric contributor with the hydroxyl radical as shown in the case of m/z = 69 for isoprene and furan, which are nominal isobars but have rate coefficients that differ by one order of magnitude. It also demonstrates a new safer and portable substitute for pressurized zero air bottles that have been required thus far in CRM OH reactivity deployments. VOC–OHM successfully couples the typical VOC and CRM experimental set ups without undermining the PTR-MS's ability to measure either parameter. The design of the VOC–OHM system, its validation, optimization and results of field tests are described in detail. The VOC–OHM system measures the ambient VOCs and OH reactivity every hour for ∼20 min durations each, with an ambient data gap of ∼13 min in between. Thus rapid temporal changes in the ambient chemical composition and reactivity are easily quantified. The sampling periods and VOC speciation achieved using VOC–OHM can be customized depending on user preferences, providing more options for the majority of users possessing a single PTR-MS.
[1546] Romano, A., L. Fischer, J. Herbig, H. Campbell-Sills, J. Coulon, P. Lucas, L. Cappellin, and F. Biasioli, "Wine analysis by FastGC proton-transfer reaction-time-of-flight-mass spectrometry", International Journal of Mass Spectrometry, vol. 369, pp. 81 - 86, 2014.
Link: http://www.sciencedirect.com/science/article/pii/S1387380614002127
Abstract
<p>Abstract Proton transfer reaction-mass spectrometry (PTR-MS) has successfully been applied to a wide variety of food matrices, nevertheless the reports about the use of PTR-MS in the analysis of alcoholic beverages remain anecdotal. Indeed, due to the presence of ethanol in the sample, PTR-MS can only be employed after dilution of the headspace or at the expense of radical changes in the operational conditions. In the present research work, PTR-ToF-MS was coupled to a prototype FastGC system allowing for a rapid (90&nbsp;s) chromatographic separation of the sample headspace prior to PTR-MS analysis. The system was tested on red wine: the FastGC step allowed to rule out the effect of ethanol, eluted from the column during the first 8&nbsp;s, allowing PTR-MS analysis to be carried out without changing the ionization conditions. Eight French red wines were submitted to analysis and could be separated on the basis of the respective grape variety and region of origin. In comparison to the results obtained by direct injection, FastGC provided additional information, thanks to a less drastic dilution of the sample and due to the chromatographic separation of isomers. This was achieved without increasing duration and complexity of the analysis.</p>
2013
[1470] Biasioli, F., "10 years PTR-MS at FEM: from sensory analysis to omics", CONFERENCE SERIES, 1, 2013.
Link: http://www.ionicon.com/sites/default/files/uploads/doc/contributions_ptr_ms_Conference_6.pdf
[Park2013] Park, J-H.., A.. H. Goldstein, J.. Timkovsky, S.. Fares, R.. Weber, J.. Karlik, and R.. Holzinger, "Active atmosphere-ecosystem exchange of the vast majority of detected volatile organic compounds.", Science, vol. 341, no. 6146: Department of Environmental Science, Policy, and Management, University of California at Berkeley, Berkeley, CA 94720, USA., pp. 643–647, Aug, 2013.
Link: http://nature.berkeley.edu/ahg/pubs/Park%20et%20al%20Science%202013.pdf
Abstract
<p>Numerous volatile organic compounds (VOCs) exist in Earth&#39;s atmosphere, most of which originate from biogenic emissions. Despite VOCs&#39; critical role in tropospheric chemistry, studies for evaluating their atmosphere-ecosystem exchange (emission and deposition) have been limited to a few dominant compounds owing to a lack of appropriate measurement techniques. Using a high-mass resolution proton transfer reaction-time of flight-mass spectrometer and an absolute value eddy-covariance method, we directly measured 186 organic ions with net deposition, and 494 that have bidirectional flux. This observation of active atmosphere-ecosystem exchange of the vast majority of detected VOCs poses a challenge to current emission, air quality, and global climate models, which do not account for this extremely large range of compounds. This observation also provides new insight for understanding the atmospheric VOC budget.</p>
[1455] Schmidberger, T., and R. Huber, "Advanced off-gas measurement using proton transfer reaction mass spectrometry to predict cell culture parameters", BMC Proceedings, vol. 7, pp. P14, 2013.
Link: http://www.biomedcentral.com/1753-6561/7/S6/P14
Abstract
<p>Mass spectrometry is a well-known technology to detect O2 and CO2 in the off-gas of cell culture fermentations. In contrast to classical mass spectrometers, the proton transfer reaction mass spectrometer (PTR MS) enables the noninvasive analysis of a broad spectrum of volatile organic compounds (VOCs) in real time. The thereby applied soft ionization technology generates spectra of less fragmentation and facilitates their interpretation. This gave us the possibility to identify process relevant compounds in the bioreactor off-gas stream in addition to O2 and CO2. In our study the PTR-MS technology was applied for the first time to monitor volatile organic compounds (VOC) and to predict cell culture parameters in an industrial mammalian cell culture process.</p>

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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.
Link

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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