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Scientific Articles - PTR-MS Bibliography

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Found 32 results
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2015
[1793] Sun, K., K. Cady-Pereira, D. J. Miller, L. Tao, M. A. Zondlo, J. B. Nowak, JA. Neuman, T. Mikoviny, M. Müller, A. Wisthaler, et al., "Validation of TES ammonia observations at the single pixel scale in the San Joaquin Valley during DISCOVER-AQ", Journal of Geophysical Research: Atmospheres, vol. 120, pp. 5140–5154, 2015.
Link: http://onlinelibrary.wiley.com/doi/10.1002/2014JD022846/full
Abstract
<p>Ammonia measurements from a vehicle-based, mobile open-path sensor and those from aircraft were compared with Tropospheric Emission Spectrometer (TES) NH3 columns at the pixel scale during the NASA Deriving Information on Surface conditions from Column and Vertically Resolved Observations Relevant to Air Quality field experiment. Spatial and temporal mismatches were reduced by having the mobile laboratory sample in the same areas as the TES footprints. To examine how large heterogeneities in the NH3 surface mixing ratios may affect validation, a detailed spatial survey was performed within a single TES footprint around the overpass time. The TES total NH3 column above a single footprint showed excellent agreement with the in situ total column constructed from surface measurements with a difference of 2% (within the combined measurement uncertainties). The comparison was then extended to a TES transect of nine footprints where aircraft data (5&ndash;80&thinsp;ppbv) were available in a narrow spatiotemporal window (&lt;10&thinsp;km, &lt;1&thinsp;h). The TES total NH3 columns above the nine footprints agreed to within 6% of the in situ total columns derived from the aircraft-based measurements. Finally, to examine how TES captures surface spatial gradients at the interpixel scale, ground-based, mobile measurements were performed directly underneath a TES transect, covering nine footprints within &plusmn;1.5&thinsp;h of the overpass. The TES total columns were strongly correlated (R2&thinsp;=&thinsp;0.82) with the median NH3 mixing ratios measured at the surface. These results provide the first in situ validation of the TES total NH3 column product, and the methodology is applicable to other satellite observations of short-lived species at the pixel scale.</p>
[1651] R. del Rio, F., M.E.. OHara, A.. Holt, P.. Pemberton, T.. Shah, T.. Whitehouse, and C.A.. Mayhew, "Volatile Biomarkers in Breath Associated With Liver Cirrhosis - Comparisons of Pre- and Post-liver Transplant Breath Samples", EBioMedicine, Jul, 2015.
Link: http://dx.doi.org/10.1016/j.ebiom.2015.07.027
Abstract
Background: The burden of liver disease in the UK has risen dramatically and there is a need for improved diagnostics. Aims: To determine which breath volatiles are associated with the cirrhotic liver and hence diagnostically useful. Methods: A two-stage biomarker discovery procedure was used. Alveolar breath samples of 31 patients with cirrhosis and 30 healthy controls were mass spectrometrically analysed and compared (stage 1). 12 of these patients had their breath analysed after liver transplant (stage 2). Five patients were followed longitudinally as in-patients in the posttransplant period. Results: Seven volatileswere elevated in the breath of patients versus controls. Of these, five showed statistically significant decrease post-transplant: limonene, methanol, 2-pentanone, 2-butanone and carbon disulfide. On an individual basis limonene has the best diagnostic capability (the area under a receiver operating characteristic curve (AUROC) is 0.91), but this is improved by combining methanol, 2-pentanone and limonene (AUROC curve 0.95). Following transplant, limonene shows wash-out characteristics. Conclusions: Limonene,methanol and 2-pentanone are breathmarkers for a cirrhotic liver. This study raises the potential to investigate these volatiles asmarkers for early-stage liver disease. Bymonitoring the wash-out of limonene following transplant, graft liver function can be non-invasively assessed.
[1706] Aprea, E., A. Romano, E. Betta, F. Biasioli, L. Cappellin, M. Fanti, and F. Gasperi, "Volatile compound changes during shelf life of dried Boletus edulis: comparison between SPME-GC-MS and PTR-ToF-MS analysis.", J Mass Spectrom, vol. 50, pp. 56–64, Jan, 2015.
Link: http://dx.doi.org/10.1002/jms.3469
Abstract
<p>Drying process is commonly used to allow long time storage of valuable porcini mushrooms (Boletus edulis). Although considered a stable product dried porcini flavour changes during storage. Monitoring of volatile compounds during shelf life may help to understand the nature of the observed changes. In the present work two mass spectrometric techniques were used to monitor the evolution of volatile compounds during commercial shelf life of dried porcini. Solid phase microextraction (SPME) coupled to gas chromatography - mass spectrometry (GC-MS) allowed the identification of 66 volatile compounds, 36 of which reported for the first time, monitored during the commercial shelf life of dried porcini. Proton transfer reaction - time of flight - mass spectrometry (PTR-ToF-MS) , a direct injection mass spectrometric technique, was shown to be a fast and sensitive instrument for the general monitoring of volatile compound evolution during storage of dried porcini. Furthermore, PTR-ToF-MS grants access to compounds whose determination would otherwise require lengthy pre-concentration and/or derivatization steps such as ammonia and small volatile amines. The two techniques, both used for the first time to study dried porcini, provided detailed description of time evolution of volatile compounds during shelf life. Alcohols, aldehydes, ketones and monoterpenes diminish during the storage while carboxylic acids, pyrazines, lactones and amines increase. The storage temperature modifies the rate of the observed changes influencing the final quality of the dried porcini. We showed the advantages of both techniques, suggesting a strategy to be adopted to follow time evolution of volatile compounds in food products during shelf life, based on the identification of compounds by GC-MS and the rapid time monitoring by PTR-ToF-MS measurements in order to maximize the advantages of both techniques.</p>
[1709] Federico, V., T. Cosimo, P. Antonio, B. Nadia, L. Valentina, M. Stefano, and A. Amedeo, "Volatile organic compounds in truffle (Tuber magnatum Pico): comparison of samples from different regions of Italy and from different seasons.", Sci Rep, vol. 5, pp. 12629, 2015.
Link: http://dx.doi.org/10.1038/srep12629
Abstract
<p>In this paper volatile organic compounds (VOCs) from Tuber magnatum fruiting bodies were analyzed using a PTR-TOF-MS instrument. The aim was to characterize the VOC&#39;s profile of the fruiting bodies and identify if any VOCs were specific to a season and geographical areas. Multiple factorial analysis (MFA) was carried out on the signals obtained by MS. Experiments using ITS region sequencing proved that the T. magnatum life cycle includes the formation of fruiting bodies at two different times of the year. The VOCs profiles diverge when different seasonal and geographical productions are considered. Using PTR-TOF-MS, compounds present at levels as low pptv were detected. This made it possible to determine both the origin of fruiting bodies (Alba and San Miniato) and the two biological phases of fruiting bodies formation in San Miniato truffles.</p>
2014
[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.
2013
[Simpraga2013] Šimpraga, M., H. Verbeeck, J. Bloemen, L. Vanhaecke, M. Demarcke, E. Joó, O. Pokorska, C. Amelynck, N. Schoon, J. Dewulf, et al., "Vertical canopy gradient in photosynthesis and monoterpenoid emissions: An insight into the chemistry and physiology behind", Atmospheric Environment: Elsevier, 2013.
Link: http://www.sciencedirect.com/science/article/pii/S1352231013005785
Abstract
It is well known that vertical canopy gradients and varying sky conditions influence photosynthesis (Pn), specific leaf area (SLA), leaf thickness (LT) and leaf pigments (lutein, â-carotene and chlorophyll). In contrast, little is known about these effects on monoterpenoid (MT) emissions. Our study examines simultaneously measured Pn, MT emissions and the MT/Pn ratio along the canopy of an adult European beech tree (Fagus sylvatica L.) in natural forest conditions. Dynamic branch enclosure systems were used at four heights in the canopy (7, 14, 21 and 25 m) in order to establish relationships and better understand the interaction between Pn and MT emissions under both sunny and cloudy sky conditions. Clear differences in Pn, MT emissions and the MT/Pn ratio were detected within the canopy. The highest Pn rates were observed in the sun leaves at 25 m due to the higher intercepted light levels, whereas MT emissions (and the MT/Pn ratio) were unexpectedly highest in the semi-shaded leaves at 21 m. The higher Pn rates and, apparently contradictory, lower MT emissions in the sun leaves may be explained by the hypothesis of Owen and Peñuelas (2005), stating synthesis of more photo-protective carotenoids may decrease the emissions of volatile isoprenoids (including MTs) because they both share the same biochemical precursors. In addition, leaf traits like SLA, LT and leaf pigments clearly differed with height in the canopy, suggesting that the leaf's physiological status cannot be neglected in future research on biogenic volatile organic compounds (BVOCs) when aiming at developing new and/or improved emission algorithms.
[Benjamin2013] Benjamin, O.., P.. Silcock, J.. Beauchamp, A.. Buettner, and D.. W. Everett, "Volatile release and structural stability of β-lactoglobulin primary and multilayer emulsions under simulated oral conditions.", Food Chem, vol. 140, no. 1-2: Riddet Institute, Palmerston North, New Zealand. ofir.benjamin@otago.ac.nz, pp. 124–134, Sep, 2013.
Link: http://dx.doi.org/10.1016/j.foodchem.2013.02.043
Abstract
The relationship between emulsion structure and the release of volatile organic compounds (VOCs) was investigated using a model mouth system under oral conditions (tongue mastication, artificial saliva, pH and salt). The VOCs were monitored on-line by proton transfer reaction mass spectrometry (PTR-MS). Two types of emulsion system were compared: primary and multilayer oil-in-water (P-O/W, M-O/W) emulsions consisting of soy oil coated by β-lactoglobulin and pectin layers. The P-O/W emulsions showed intensive flocculation at pH 5 and above 200 mM NaCl where the electrostatic repulsive charge was at a minimum. Bridging and depletion flocculation were mostly observed for P-O/W emulsions containing artificial saliva with 1 wt% mucin. The VOC release was found to increase when the emulsion droplets flocculated, thus changing the oil volume phase distribution. The adsorbed pectin layer stabilised the emulsion structure under conditions of short-time oral processing, and hindered the release of hydrophobic VOCs.
2012
[Ni2012] Ni, J-Q., W. P. Robarge, C. Xiao, and A. J. Heber, "Volatile organic compounds at swine facilities: a critical review.", Chemosphere, vol. 89, no. 7: Department of Agricultural and Biological Engineering, Purdue University, West Lafayette, IN 47907, USA. jiqin@purdue.edu, pp. 769–788, Oct, 2012.
Link: http://dx.doi.org/10.1016/j.chemosphere.2012.04.061
Abstract
Volatile organic compounds (VOCs) are regulated aerial pollutants that have environmental and health concerns. Swine operations produce and emit a complex mixture of VOCs with a wide range of molecular weights and a variety of physicochemical properties. Significant progress has been made in this area since the first experiment on VOCs at a swine facility in the early 1960s. A total of 47 research institutions in 15 North American, European, and Asian countries contributed to an increasing number of scientific publications. Nearly half of the research papers were published by U.S. institutions. Investigated major VOC sources included air inside swine barns, in headspaces of manure storages and composts, in open atmosphere above swine wastewater, and surrounding swine farms. They also included liquid swine manure and wastewater, and dusts inside and outside swine barns. Most of the sample analyses have been focusing on identification of VOC compounds and their relationship with odors. More than 500 VOCs have been identified. About 60% and 10% of the studies contributed to the quantification of VOC concentrations and emissions, respectively. The largest numbers of VOC compounds with reported concentrations in a single experimental study were 82 in air, 36 in manure, and 34 in dust samples. The relatively abundant VOC compounds that were quantified in at least two independent studies included acetic acid, butanoic acid (butyric acid), dimethyl disulfide, dimethyl sulfide, iso-valeric, p-cresol, propionic acid, skatole, trimethyl amine, and valeric acid in air. They included acetic acid, p-cresol, iso-butyric acid, butyric acid, indole, phenol, propionic acid, iso-valeric acid, and skatole in manure. In dust samples, they were acetic acid, propionic acid, butyric acid, valeric acid, p-cresol, hexanal, and decanal. Swine facility VOCs were preferentially bound to smaller-size dusts. Identification and quantification of VOCs were restricted by using instruments based on gas Chromatography (GC) and liquid chromatography (LC) with different detectors most of which require time-consuming procedures to obtain results. Various methodologies and technologies in sampling, sample preparation, and sample analysis have been used. Only four publications reported using GC based analyzers and PTR-MS (proton-transfer-reaction mass spectrometry) that allowed continuous VOC measurement. Because of this, the majority of experimental studies were only performed on limited numbers of air, manure, or dust samples. Many aerial VOCs had concentrations that were too low to be identified by the GC peaks. Although VOCs emitted from swine facilities have environmental concerns, only a few studies investigated VOC emission rates, which ranged from 3.0 to 176.5mgd(-1)kg(-1) pig at swine finishing barns and from 2.3 to 45.2gd(-1)m(-2) at manure storages. Similar to the other pollutants, spatial and temporal variations of aerial VOC concentrations and emissions existed and were significantly affected by manure management systems, barn structural designs, and ventilation rates. Scientific research in this area has been mainly driven by odor nuisance, instead of environment or health concerns. Compared with other aerial pollutants in animal agriculture, the current scientific knowledge about VOCs at swine facilities is still very limited and far from sufficient to develop reliable emission factors.
[Weise2012] Weise, T., M. Kai, A. Gummesson, A. Troeger, S. { von Reuß}, S. Piepenborn, F. Kosterka, M. Sklorz, R. Zimmermann, W. Francke, et al., "Volatile organic compounds produced by the phytopathogenic bacterium Xanthomonas campestris pv. vesicatoria 85-10.", Beilstein J Org Chem, vol. 8: University of Rostock, Institute of Biological Sciences, Albert-Einstein-Str. 3, 18059 Rostock, Germany., pp. 579–596, 2012.
Link: http://dx.doi.org/10.3762/bjoc.8.65
Abstract
Xanthomonas campestris is a phytopathogenic bacterium and causes many diseases of agricultural relevance. Volatiles were shown to be important in inter- and intraorganismic attraction and defense reactions. Recently it became apparent that also bacteria emit a plethora of volatiles, which influence other organisms such as invertebrates, plants and fungi. As a first step to study volatile-based bacterial-plant interactions, the emission profile of Xanthomonas c. pv. vesicatoria 85-10 was determined by using GC/MS and PTR-MS techniques. More than 50 compounds were emitted by this species, the majority comprising ketones and methylketones. The structure of the dominant compound, 10-methylundecan-2-one, was assigned on the basis of its analytical data, obtained by GC/MS and verified by comparison of these data with those of a synthetic reference sample. Application of commercially available decan-2-one, undecan-2-one, dodecan-2-one, and the newly synthesized 10-methylundecan-2-one in bi-partite Petri dish bioassays revealed growth promotions in low quantities (0.01 to 10 ?mol), whereas decan-2-one at 100 ?mol caused growth inhibitions of the fungus Rhizoctonia solani. Volatile emission profiles of the bacteria were different for growth on media (nutrient broth) with or without glucose.
2011
[Gros2011] Gros, V., C. Gaimoz, F. Herrmann, T. Custer, J. Williams, B. Bonsang, S. Sauvage, N. Locoge, O. d'Argouges, R. Sarda-Esteve, et al., "Volatile organic compounds sources in Paris in spring 2007. Part I: qualitative analysis", Environmental Chemistry, vol. 8, no. 1: CSIRO, pp. 74–90, 2011.
Link: http://www.publish.csiro.au/?paper=EN10068
Abstract
High-time-resolution measurements of volatile organic compounds (VOCs) were performed in the Paris city centre in spring 2007. The studied region was influenced mainly by air masses of two origins: (1) from the Atlantic Ocean, and (2) from north-eastern Europe. Although the baseline levels (i.e. those not influenced by local emissions) of non-methane hydrocarbons (NMHC) and CO were only slightly impacted by changes in the air-mass origin, oxygenated compounds such as acetone and methanol showed much higher baseline levels in continentally influenced air masses. This suggests that NMHC and CO mixing ratios were mainly influenced by local-to-regional-scale sources whereas oxygenated compounds had a more significant continental-scale contribution. This highlights the importance of measuring VOCs instead of NMHC alone in source classification studies. The period of Atlantic air influence was used to characterise local pollution, which was dominated by traffic-related emissions, although traffic represents the source of only one third of total VOCs emissions in the local inventory. In addition to traffic-related sources, additional sources were identified; in particular, emissions from dry-cleaning activities were identified by the use of a specific tracer (i.e. tetrachloroethylene).
2010
[Joo2010] Joó, É., H. Van Langenhove, M. Šimpraga, K. Steppe, C. Amelynck, N. Schoon, J-F. Müller, and J. Dewulf, "Variation in biogenic volatile organic compound emission pattern of Fagus sylvatica L. due to aphid infection", Atmospheric Environment, vol. 44, no. 2: Elsevier, pp. 227–234, 2010.
Link: http://www.sciencedirect.com/science/article/pii/S1352231009008553
Abstract
Volatile organic compounds (VOCs) have been the focus of interest to understand atmospheric processes and their consequences in formation of ozone or aerosol particles; therefore, VOCs contribute to climate change. In this study, biogenic VOCs (BVOCs) emitted from Fagus sylvatica L. trees were measured in a dynamic enclosure system. In total 18 compounds were identified: 11 monoterpenes (MT), an oxygenated MT, a homoterpene (C14H18), 3 sesquiterpenes (SQT), isoprene and methyl salicylate. The frequency distribution of the compounds was tested to determine a relation with the presence of the aphid Phyllaphis fagi L. It was found that linalool, (E)-β-ocimene, α-farnesene and a homoterpene identified as (E)-4,8-dimethyl-1,3,7-nonatriene (DMNT), were present in significantly more samples when infection was present on the trees. The observed emission spectrum from F. sylvatica L. shifted from MT to linalool, α-farnesene, (E)-β-ocimene and DMNT due to the aphid infection. Sabinene was quantitatively the most prevalent compound in both, non-infected and infected samples. In the presence of aphids α-farnesene and linalool became the second and third most important BVOC emitted. According to our investigation, the emission fingerprint is expected to be more complex than commonly presumed.
[Ruuskanen2010] Ruuskanen, TM., M. Müller, R. Schnitzhofer, T. Karl, M. Graus, I. Bamberger, L. Hoertnagl, F. Brilli, G. Wohlfahrt, and A. Hansel, "VOC Emission and Deposition Eddy Covariance Fluxes above Grassland using PTR-TOF", AGU Fall Meeting Abstracts, vol. 1, pp. 0219, 2010.
Link: http://adsabs.harvard.edu/abs/2010AGUFM.A53C0219R
Abstract
Eddy covariance (EC) is the preferable technique for flux measurements since it is the only direct flux determination method. It requires a continuum of high time resolution measurements (e.g. 5-20 Hz). For volatile organic compounds (VOC) soft ionization via proton transfer reaction has proven to be a quantitative method for real time mass spectrometry; here we use a proton transfer reaction time of flight mass spectrometer (PTR-TOF) for 10 Hz EC measurements of full mass spectra up to m/z 315. The mass resolution of the PTR-TOF enabled the identification of chemical formulas and separation of oxygenated and hydrocarbon species exhibiting the same nominal mass. We determined 481 ion mass peaks from ambient air concentration above a managed, temperate mountain grassland in Neustift, Stubai Valley, Austria. During harvesting we found significant fluxes of 18 compounds distributed over 43 ions, including protonated parent compounds, as well as their isotopes and fragments and VOC-H+ - water clusters. The dominant BVOC fluxes were methanol, acetaldehyde, ethanol, hexenal and other C6 leaf wound compounds, acetone, acetic acid, monoterpenes and sequiterpenes. The smallest reliable fluxes we determined were less than 0.1 nmol m-2 s-1, as in the case of sesquiterpene emissions from freshly cut grass. Terpenoids, including mono- and sesquiterpenes, were also deposited to the grassland before and after the harvesting. During cutting, total VOC emission fluxes up to 200 nmolC m-2 s-1 were measured. Methanol emissions accounted for half of the emissions of oxygenated VOCs and a third of the carbon of all measured VOC emissions during harvesting.
[1721] Insam, H., and M. S. A. Seewald, "Volatile organic compounds (VOCs) in soils", Biology and Fertility of Soils, vol. 46, pp. 199–213, Feb, 2010.
Link: http://dx.doi.org/10.1007/s00374-010-0442-3
Abstract
<p>Soils may act as sources or sinks of volatile organic compounds (VOCs). Many of the formed VOCs are produced by microorganisms, and it would be a challenge to investigate soil microbial communities by studying their VOC profile. Such &ldquo;volatilomics&rdquo; would have the advantage of avoiding extraction steps that are often a limit in genomic or proteomic approaches. Abundant literature on microbially produced VOCs is available, and in particular novel detection methods allow additional insight. The aim of this paper was to give an overview on the current knowledge of microbial VOC emissions from soils.</p>
2009
[Colomb2009] Colomb, A., V. Gros, S. Alvain, R. Sarda-Esteve, B. Bonsang, C. Moulin, T. Klüpfel, and J. Williams, "Variation of atmospheric volatile organic compounds over the Southern Indian Ocean (30–49 S)", Environmental Chemistry, vol. 6, no. 1: CSIRO, pp. 70–82, 2009.
Link: http://www.publish.csiro.au/?paper=EN08072
Abstract
Considering its size and potential importance, the ocean is poorly characterised in terms of volatile organic compounds (VOC) that play important roles in global atmospheric chemistry. In order to better understand their potential sources and sinks over the Southern Indian Austral Ocean, shipborne measurements of selected species were made during the MANCHOT campaign during December 2004, on board the research vessel Marion Dufresne. Along the transect La Réunion to Kerguelen Island, air measurements of selected VOC (including dimethylsulfide (DMS) isoprene, carbonyls and organohalogens), carbon monoxide and ozone were performed, crossing subtropical, temperate and sub-Antarctic waters as well as pronounced subtropical and sub-Antarctic oceanic fronts. The remote marine boundary layer was characterised at latitudes 45–50°S. Oceanic fronts were associated with enhanced chlorophyll and biological activity in the seawater and elevated DMS and organohalogens in the atmosphere. These were compared with a satellite-derived phytoplankton distribution (PHYSAT). Diurnal variation for isoprene, terpenes, acetone and acetaldehyde was observed, analogously to recent results observed in mesocosm experiments.
[Macatelli2009] Maçatelli, M., W. Akkermans, A. Koot, M. Buchgraber, A. Paterson, and S. van Ruth, "Verification of the geographical origin of European butters using PTR-MS", Journal of Food Composition and Analysis, vol. 22, no. 2: Elsevier, pp. 169–175, 2009.
Link: http://www.sciencedirect.com/science/article/pii/S0889157508001890
Abstract
In the present study, proton transfer reaction-mass spectrometry (PTR-MS) in combination with partial least square-discriminant analysis (PLS-DA) was evaluated as a method for the prediction of the origin of European butters. Eighty-three commercial butters from three European regions were subjected to headspace analysis using PTR-MS. Data were collected for the mass range m/z 20–150 using a dwell time of 0.2 s mass−1, resulting in a cycle time just under 30 s. The log transformed headspace concentrations of the masses were subjected to PLS-DA in order to estimate classification models for the butter samples. One model predicted the region of origin; a second set of models predicted dichotomously whether or not a butter originated from a particular EU country. The performance of each model was evaluated by means of a 10-fold double cross validation procedure. For 76% of the butters the region of origin was predicted correctly in the cross validation. The success rate of the countries, averaged over all dichotomous models, was 88% but large differences between countries were observed. Additional work is required to study the underlying factors that determine the geographical differences in butter volatile compositions.
[Taipale2009] Taipale, R., T. M. Ruuskanen, M. K. Kajos, J. Patokoski, H. Hakola, and J. Rinne, "VOC emissions from a boreal forest–direct ecosystem scale measurements by PTR-MS in 2006–2008", CONFERENCE SERIES, pp. 299, 2009.
Link: http://www.ionicon.com/sites/default/files/uploads/doc/contributions_ptr_ms_Conference_4.pdf
[Eerdekens2009] Eerdekens, G., N. Yassaa, V. Sinha, PP. Aalto, H. Aufmhoff, F. Arnold, V. Fiedler, M. Kulmala, and J. Williams, "VOC measurements within a boreal forest during spring 2005: on the occurrence of elevated monoterpene concentrations during night time intense particle concentration events", Atmos. Chem. Phys, vol. 9, no. 21, pp. 8331–8350, 2009.
Link: http://www.atmos-chem-phys.net/9/8331/2009/acp-9-8331-2009.html
Abstract
In this study we present measurements of selected trace gases and aerosols made in a boreal forest during the BACCI-QUEST IV intensive field campaign in Hyytiälä, Finland in April 2005. Springtime diel and vertical variations of VOCs are discussed in connection with the variations in other trace gases and with the prevailing meteorological conditions. A daytime and a nighttime event have been analysed in detail. The nighttime particle event occurred synchronously with huge increases in monoterpenes, while the second event type involved nucleation and was anti-correlated with sulphuric acid. Here we discuss the possible origins of these two distinct forms of aerosol production at the Hyytiälä site using the measurement data, air mass back trajectories and the optical stereoisomery of monoterpenes. Optical stereoisomery is used in source identification to distinguish between unnatural and natural monoterpene emissions.
2008
[Arendacka2008] Arendacká, B., K. Schwarz, S. Stolc, G. Wimmer, and V. Witkovský, "Variability issues in determining the concentration of isoprene in human breath by PTR-MS.", J Breath Res, vol. 2, no. 3: Institute of Measurement Science, Slovak Academy of Sciences, Bratislava, Slovakia., pp. 037007, Sep, 2008.
Link: http://dx.doi.org/10.1088/1752-7155/2/3/037007
Abstract
This paper deals with variability issues connected with the proton transfer reaction-mass spectrometry (PTR-MS) measurements of isoprene concentration. We focus on isoprene as an abundant and widely studied compound in human breath. The variability caused by the measurement process is described by the within-sample distribution. Thus, based on the formula for computing isoprene concentration that reflects the principle of the PTR-MS, a theoretical model for the within-sample distribution of isoprene concentration is suggested. This model, which assumes that the distribution is proportional to a quotient of two independent Poisson-distributed random variables, is then confronted with empirical distributions obtained from 17 breath samples collected from a healthy individual within a month. (In each sample, isoprene concentration was determined 97 times.) The empirical within-sample distributions are also compared to normal and log-normal distributions. While those seem to be satisfactory approximations, the theoretical model is found suitable only in 10 out of 17 breath samples. We also comment on the stability of samples during the measurement process in the PTR-MS instrument and, for the sake of comparison, determine the within-sample and the within-subject variability of isoprene concentrations in our data. The respective geometric standard deviations are 1.01 and 1.29.
[Solomon2008] Solomon, SJ., GW. Schade, J. Kuttippurath, A. Ladstätter-Weissenmayer, and JP. Burrows, "VOC concentrations in an indoor workplace environment of a university building", Indoor and Built Environment, vol. 17, no. 3: SAGE Publications, pp. 260–268, 2008.
Link: http://ibe.sagepub.com/content/17/3/260.short
Abstract
An indoor air quality survey was conducted at selected indoor environments in the Department of Physics and Electrical Engineering of the University of Bremen, Germany, during August 2005. The mean indoor/ outdoor (I/O) ratios of pollutants appeared to be higher than 1.0 for most volatile organic compounds (VOCs). Apart from direct emissions from indoor materials and infiltration of outdoor air, environmental tobacco smoke (ETS) was a dominant factor in indoor pollution. Pollutants which were commonly associated with cleaning products and materials, including monoterpenes, aldehydes and acetone exhibited general trends of higher concentrations indoors compared to outdoor levels. Indoor concentrations of many VOCs were found to be 2—10 times higher during weekdays as compared to the weekend, exhibiting a strong correlation with human activities. A comparison with previous studies on the health risks due to selected VOCs indicates that long-term exposure to the peak values reported in this study has potential to develop adverse health effects to the occupants whereby reducing the efficiency in the workplace.
[Ruth2008] van Ruth, S. M., J. Frasnelli, and L. Carbonell, "Volatile flavour retention in food technology and during consumption: Juice and custard examples", Food Chemistry, vol. 106, no. 4: Elsevier, pp. 1385–1392, 2008.
Link: http://www.sciencedirect.com/science/article/pii/S0308814607009132
Abstract
In this study two aspects of the influence of water on flavour retention were evaluated. The first part of the study was focused on the influence of dehydration and subsequent reconstitution of mandarin juices, which was examined by headspace Proton Transfer Reaction Mass Spectrometry. The different treatments were discriminated by their mass spectra with help of Principal Component Analysis. The second part of the study concerned intranasal volatile flavour retention during food consumption. Volatile flavour concentrations were measured at four intranasal locations in nine subjects during consumption of custard desserts. Differences between the locations indicated various degrees of retention of volatile flavour compounds by the watery mucous in the nasal tract.
2007
[Shaw2007] Shaw, S. L., F. M. Mitloehner, W. Jackson, E. J. Depeters, J. G. Fadel, P. H. Robinson, R. Holzinger, and A. H. Goldstein, "Volatile organic compound emissions from dairy cows and their waste as measured by proton-transfer-reaction mass spectrometry.", Environ Sci Technol, vol. 41, no. 4: Department of Environmental Science, Policy, and Management, University of California, Berkeley, Hilgard Hall, Berkeley, California 94720, USA. slshaw@alum.mit.edu, pp. 1310–1316, Feb, 2007.
Link: http://pubs.acs.org/doi/abs/10.1021/es061475e
Abstract
California dairies house approximately 1.8 million lactating and 1.5 million dry cows and heifers. State air regulatory agencies view these dairies as a major air pollutant source, but emissions data are sparse, particularly for volatile organic compounds (VOCs). The objective of this work was to determine VOC emissions from lactating and dry dairy cows and their waste using an environmental chamber. Carbon dioxide and methane were measured to provide context for the VOCs. VOCs were measured by proton-transfer-reaction mass spectrometry (PTR-MS). The compounds with highest fluxes when cows plus waste were present were methanol, acetone + propanal, dimethylsulfide, and m/z 109 (likely 4-methyl-phenol). The compounds with highest fluxes from fresh waste (urine and feces) were methanol, m/z 109, and m/z 60 (likely trimethylamine). Ethanol fluxes are reported qualitatively, and several VOCs that were likely emitted (formaldehyde, methylamine, dimethylamine) were not detectable by PTR-MS. The sum of reactive VOC fluxes measured when cows were present was a factor of 6-10 less than estimates historically used for regulatory purposes. In addition, ozone formation potentials of the dominant VOCs were -10% those of typical combustion or biogenic VOCs. Thus dairy cattle have a comparatively small impact on ozone formation per VOC mass emitted.
[Filella2007] Filella, I., M. J. Wilkinson, J. Llusia, N. C Hewitt, and J. Penuelas, "Volatile organic compounds emissions in Norway spruce (Picea abies) in response to temperature changes", Physiologia Plantarum, vol. 130, no. 1: Wiley Online Library, pp. 58–66, 2007.
Link: http://onlinelibrary.wiley.com/doi/10.1111/j.1399-3054.2007.00881.x/full
Abstract
Volatile organic compound (VOC) emissions from Norway spruce (Picea abies) saplings were monitored in response to a temperature ramp. Online measurements were made with a proton transfer reaction – mass spectrometer under controlled conditions, together with plant physiological variables. Masses corresponding to acetic acid and acetone were the most emitted VOCs. The emission rates of m137 (monoterpenes), m59 (acetone), m33 (methanol), m83 (hexanal, hexenals), m85 (hexanol) and m153 (methyl salicylate, MeSa) increased exponentially with temperature. The emission of m61 (acetic acid) and m45 (acetaldehyde), however, increased with temperature only until saturation around 30°C, closely following the pattern of transpiration rates. These results indicate that algorithms that use only incident irradiance and leaf temperature as drivers to predict VOC emission rates may be inadequate for VOCs with lower H, and consequently higher sensitivity to stomatal conductance.
[Galbally2007] Galbally, I. E., S. J. Lawson, I. A. Weeks, S. T. Bentley, R. W. Gillett, M. Meyer, and A. H. Goldstein, "Volatile organic compounds in marine air at Cape Grim, Australia", Environmental Chemistry, vol. 4, no. 3: CSIRO, pp. 178–182, 2007.
Link: http://www.publish.csiro.au/?paper=EN07024
Abstract
Measurements were made of volatile organic compounds (VOCs) at Cape Grim using proton transfer reaction mass spectrometry (PTR-MS) during the Precursors to Particles (P2P) Campaign from 10 February to 1 March 2006. Approximately 14 days of clean air data were obtained along with 4 days of data from when polluted air, first from a smoke plume from a fire on Robbins Island adjacent to the station and then air from Victoria, was present. This paper deals with the results obtained in clean air, the focus of the P2P campaign. The protonated masses and probable VOCs measured in the clean marine air were: methanol, 33; acetonitrile, 42; acetaldehyde, 45; acetone, 59; isoprene, 69; methylvinyl ketone/methacrolein (MVK/MACR), 71; methylethyl ketone, 73; and benzene, 79. The measurements at Cape Grim were in some cases near the detection limit and an analytical challenge. The range of concentrations detected in clean maritime air, the relationship to the limited range of previous measurements in marine air in the Northern Hemisphere tropics, and the physical, chemical and biological processes controlling these compounds in the marine air are discussed. The methanol concentrations observed at Cape Grim are consistent with global modelling, incorporating sources that are mainly of vegetation origin. Isoprene has recently been implicated as a precursor to cloud condensation nuclei over the Southern Ocean. In this snapshot of observations at Cape Grim, Tasmania, isoprene and the isoprene oxidation products MVK and MACR appeared to be absent in air from the Southern Ocean. However, isoprene has a very short atmospheric lifetime and the spatial distribution of its emissions may be very heterogeneous. The concentrations of the other VOCs in marine air at Cape Grim, acetonitrile, acetaldehyde, acetone, methylethyl ketone and benzene, were typically a factor of four lower than that observed over the remote tropical ocean in the Northern Hemisphere. The lower concentrations of carbonyls and their precursor hydrocarbons may indicate a limitation on ozone production potential in the Southern Hemisphere compared with the Northern Hemisphere troposphere.
2006
[Grabmer2006] Grabmer, W., J. Kreuzwieser, A. Wisthaler, C. Cojocariu, M. Graus, H. Rennenberg, D. Steigner, R. Steinbrecher, and A. Hansel, "VOC emissions from Norway spruce ( Picea abies L.[Karst]) twigs in the field�Results of a dynamic enclosure study", Atmospheric Environment, vol. 40: Elsevier, pp. 128–137, 2006.
Link: http://www.sciencedirect.com/science/article/pii/S135223100600327X
Abstract
During the 2002 summer intensive field campaign of BEWA2000 a proton-transfer-reaction mass spectrometer (PTR-MS) was used for online determination of volatile organic compounds (VOC) emitted by Norway spruce (Picea abies L. [Karst]) twigs in a dynamic sampling enclosure. Emissions of isoprenoids (isoprene and monoterpenes) and oxygenated VOC (OVOC; acetaldehyde, acetone, methanol, and ethanol) were investigated. Emissions showed clear diurnal patterns with high daytime emission rates amounting to 1.8 μg C g−1 dwt h−1 for the sum of monoterpenes and in the range of 0.1 to 0.6 μg C g−1 dwt h−1 for isoprene>acetone>ethanol>methanol. Data were used to validate existing models on isoprene and monoterpene emissions and to discuss environmental and physiological factors affecting VOC emissions. Isoprene and acetaldehyde emission rates were best modelled applying the Guenther 1993 temperature and solar radiation algorithm. Emissions of monoterpenes, acetone and ethanol were best described by a temperature-only exponential algorithm. Using these model approaches a maximum emission variability of 66% was covered (isoprene). Poor r2 values ranging from 0.15 to 0.42 were typical for oxygenated VOC emission modelling indicating the need for model improvement e.g. development of process-based models describing the emission as a result of biochemical de novo synthesis as well as physico-chemical transport properties inside the leaves.

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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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