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Found 35 results
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2018
[1852] Sanchez, K. J., C-L. Chen, L. M. Russell, R. Betha, J. Liu, D. J. Price, P. Massoli, L. D. Ziemba, E. C. Crosbie, R. H. Moore, et al., "Substantial Seasonal Contribution of Observed Biogenic Sulfate Particles to Cloud Condensation Nuclei", Scientific Reports, vol. 8, feb, 2018.
Link: https://www.nature.com/articles/s41598-018-21590-9
Abstract
<p>Biogenic sources contribute to cloud condensation nuclei (CCN) in the clean marine atmosphere, but few measurements exist to constrain climate model simulations of their importance. The chemical composition of individual atmospheric aerosol particles showed two types of sulfate-containing particles in clean marine air masses in addition to mass-based Estimated Salt particles. Both types of sulfate particles lack combustion tracers and correlate, for some conditions, to atmospheric or seawater dimethyl sulfide (DMS) concentrations, which means their source was largely biogenic. The first type is identified as New Sulfate because their large sulfate mass fraction (63% sulfate) and association with entrainment conditions means they could have formed by nucleation in the free troposphere. The second type is Added Sulfate particles (38% sulfate), because they are preexisting particles onto which additional sulfate condensed. New Sulfate particles accounted for 31% (7 cm&minus;3) and 33% (36 cm&minus;3) CCN at 0.1% supersaturation in late-autumn and late-spring, respectively, whereas sea spray provided 55% (13 cm&minus;3) in late-autumn but only 4% (4 cm&minus;3) in late-spring. Our results show a clear seasonal difference in the marine CCN budget, which illustrates how important phytoplankton-produced DMS emissions are for CCN in the North Atlantic.</p>
2017
[1817] Materić, D., M. Lanza, P. Sulzer, J. Herbig, D. Bruhn, V. Gauci, N. Mason, and C. Turner, "Selective reagent ion-time of flight-mass spectrometry study of six common monoterpenes", International Journal of Mass Spectrometry, jun, 2017.
Link: http://www.sciencedirect.com/science/article/pii/S1387380617303044?via%3Dihub
Abstract
<p>One of the most common volatile organic compounds (VOCs) group is monoterpenes. Monoterpenes share the molecular formula C10H16, they are usually cyclic and have a pleasant smell. The most common monoterpenes are limonene (present in citrus fruits) and α-pinene (present in conifers&rsquo; resin). Different monoterpenes have different chemical, biological and ecological properties thus it is experimentally very important to be able to differentiate between them in real time. Real time instruments such as Proton Transfer Reaction-Time of Flight-Mass Spectrometry (PTR-ToF-MS), offer a real time solution for monoterpene measurement but at the cost of selectivity resulting in all monoterpenes being seen at the same m/z. In this work we used Selective Reagent Ion-Time of Flight-Mass Spectrometry (SRI/PTR-ToF-MS) in order to explore the differences in ion branching when different ionizations (H3O+, NO+ and O2+) and different drift tube reduced field energies (E/N) were used. We report a comprehensive ion library with many unique features, characteristic for individual monoterpenes.</p>
[1823] Chandra, B.P.., V. Sinha, H. Hakkim, and B. Sinha, "Storage stability studies and field application of low cost glass flasks for analyses of thirteen ambient {VOCs} using proton transfer reaction mass spectrometry", International Journal of Mass Spectrometry, vol. 419, pp. 11–19, aug, 2017.
Link: http://www.sciencedirect.com/science/article/pii/S138738061730043X?via%3Dihub
Abstract
<p>Ambient volatile organic compounds play a key role in atmospheric chemistry and air pollution studies due to their chemical reactivity and in several instances high toxicity. Quantification of ambient whole air samples which contain reactive and short-lived VOCs such as acetaldehyde, isoprene, dimethylsulphide and trimethylbenzenes at ppt-ppb concentrations is analytically challenging and generally accomplished using online proton transfer reaction mass spectrometry. Deployment of online instrumentation is still not feasible in several regions of the world due to practical constraints (power, safety issues). Consequently there is paucity of VOC data in vast regions of the world. We present here, the validation and application of a novel method for ambient VOC speciation and emission factor studies using low cost (&lt;100 USD) whole air glass flask samplers and offline proton transfer reaction mass spectrometry that can help reduce the paucity of VOC datasets. Experiments to assess the stability during storage of thirteen VOCs, many of which are very reactive, showed that acetaldehyde, acetonitrile, acetone, dimethylsulphide, methyl vinyl and methyl ethyl ketones, benzene, xylenes, trimethylbenzenes and monoterpenes can be quantified reproducibly within the respective precision error (e.g. 40% at 100ppt α-pinene and 3% at 13 ppb acetaldehyde) between collection and storage (at &gt;95% confidence), for samples analyzed within 10 days of collection. For toluene and isoprene, similar results were obtained until day 9 and 1, respectively and at confidence &gt;70%, over the 10 day period. A storage artefact was observed for methanol resulting in higher analytical uncertainty of upto 40%. We applied the method for measuring toluene/benzene emission ratios and aromatic VOCs in traffic plumes, and determining VOC emission factors (gVOC/kg fuel) from an agricultural wheat straw fire in India. The results of this study demonstrate that use of the low cost glass flask samplers described herein can significantly improve acquisition of spatially and temporally resolved datasets for atmospheric chemistry and air quality studies at sites where online deployment of instruments remains unfeasible.</p>
2016
[1718] Sahu, L.. K., R. Yadav, and D. Pal, "Source identification of VOCs at an urban site of western India: Effect of marathon events and anthropogenic emissions", J. Geophys. Res. Atmos., pp. n/a–n/a, 2016.
Link: http://dx.doi.org/10.1002/2015JD024454
Abstract
<p>Ambient volatile organic compounds (VOCs) were measured using a high-resolution proton transfer reaction-time of flight-mass spectrometer at an urban site of Ahmedabad in India during the winter season in 2014. Mixing ratios of VOCs show large diurnal and day-to-day variations. Although strongly influenced by local emissions, periods of higher VOCs were observed during transport from the polluted Indo-Gangetic Plains than those from the cleaner Thar Desert. However with different rates, VOCs decreased exponentially with increasing wind speed. Relative abundance of methanol varied with weather conditions contributing highest and lowest under fog and clear-sky conditions, respectively. Among the compounds reported here, oxygenated VOCs (OVOCs) contribute to a large fraction (67&ndash;85%) with methanol being most abundant (40&ndash;58%). In spite of predominant vehicular emissions, diurnal distribution and emission ratios (ERs) of several VOCs indicate the role of biogenic and secondary sources. The ratios of isoprene/benzene and OVOCs/benzene show significant enhancements during daytime suggesting their contributions from biogenic and secondary sources. During marathon and cyclothon events, mixing ratios of VOCs were 2&ndash;10 times higher compared to a normal Sunday. The ERs of VOCs estimated using the nighttime data on marathon day are well within the range of values reported for several megacities of the world. The average contributions of primary anthropogenic sources to acetaldehyde, acetone, and isoprene were 44&thinsp;&plusmn;&thinsp;06%, 45&thinsp;&plusmn;&thinsp;07%, and 63&thinsp;&plusmn;&thinsp;12%, respectively. During cloudy condition, the increase in anthropogenic contribution to acetaldehyde (&nbsp;10%), acetone (9%) and isoprene (30%) is due to reduction in biogenic emissions and secondary formation of these VOCs.</p>
[1765] Peinado, I.., M.. Mason, A.. Romano, F.. Biasioli, and M.. Scampicchio, "Stability of beta-carotene in polyethylene oxide electrospun nanofibers", Applied Surface Science, vol. 370, pp. 111–116, May, 2016.
Link: http://dx.doi.org/10.1016/j.apsusc.2016.02.150
Abstract
<p>b-carotene (bc) was successfully incorporated into electrospun nanofibers of poly-(ethylene oxide) (PEO)with the aim of prolonging its shelf life and thermal stability. The physical and thermal properties of the bc-PEO-nanofibers were determined by scanning electron microscopy (SEM), color analysis, and differ-ential scanning calorimetry (DSC). The nanofibers of PEO and bc-PEO exhibited average fiber diameters of320 &plusmn; 46 and 230 &plusmn; 21 nm, with colorimetric coordinates L* = 95.7 &plusmn; 2.4 and 89.4 &plusmn; 4.6 and b* = &minus;0.5 &plusmn; 0.1and 6.2 &plusmn; 3.0 respectively. Thermogravimetric analysis coupled with Proton Transfer&ndash;Mass Spectroscopy(TGA/PTR-MS) demonstrated that coated bc inside PEO nanofibers increased thermal stability when compared to standard bc in powder form. In addition, b-carotene in the membranes showed higher stabilityduring storage when compared with b-carotene in solution with a decrease in concentration of 57 &plusmn; 4%and 70 &plusmn; 2% respectively, thus should extend the shelf life of this compound. Also, TGA coupled withPTR&ndash;MS resulted in a promising technique to online-monitoring thermal degradation.</p>
2015
[1638] Lanza, M., J. W Acton, P. Sulzer, K. Breiev, S. Jürschik, A. Jordan, E. Hartungen, G. Hanel, L. Märk, T. D. Märk, et al., "Selective reagent ionisation-time of flight-mass spectrometry: a rapid technology for the novel analysis of blends of new psychoactive substances.", J Mass Spectrom, vol. 50, pp. 427–431, Feb, 2015.
Link: http://dx.doi.org/10.1002/jms.3514
Abstract
<p>In this study we demonstrate the potential of selective reagent ionisation-time of flight-mass spectrometry for the rapid and selective identification of a popular new psychoactive substance blend called &#39;synthacaine&#39;, a mixture that is supposed to imitate the sensory and intoxicating effects of cocaine. Reactions with H3O(+) result in protonated parent molecules which can be tentatively assigned to benzocaine and methiopropamine. However, by comparing the product ion branching ratios obtained at two reduced electric field values (90 and 170 Td) for two reagent ions (H3O(+) and NO(+)) to those of the pure chemicals, we show that identification is possible with a much higher level of confidence then when relying solely on the m/z of protonated parent molecules. A rapid and highly selective analytical identification of the constituents of a recreational drug is particularly crucial to medical personnel for the prompt medical treatment of overdoses, toxic effects or allergic reactions.</p>
[1576] Lanza, M., J. W. Acton, P. Sulzer, K. Breiev, S. Juerschik, A. Jordan, E. Hartungen, G. Hanel, L. Maerk, T. D. Maerk, et al., "Selective reagent ionisation-time of flight-mass spectrometry: a rapid technology for the novel analysis of blends of new psychoactive substances", Journal of Mass Spectrometry, vol. 50, pp. 427–431, 2015.
Link: http://dx.doi.org/10.1002/jms.3514
Abstract
In this study we demonstrate the potential of selective reagent ionisation-time of flight-mass spectrometry for the rapid and selective identification of a popular new psychoactive substance blend called ‘synthacaine’, a mixture that is supposed to imitate the sensory and intoxicating effects of cocaine. Reactions with H3O+ result in protonated parent molecules which can be tentatively assigned to benzocaine and methiopropamine. However, by comparing the product ion branching ratios obtained at two reduced electric field values (90 and 170 Td) for two reagent ions (H3O+ and NO+) to those of the pure chemicals, we show that identification is possible with a much higher level of confidence then when relying solely on the m/z of protonated parent molecules. A rapid and highly selective analytical identification of the constituents of a recreational drug is particularly crucial to medical personnel for the prompt medical treatment of overdoses, toxic effects or allergic reactions. Copyright © 2015 John Wiley & Sons, Ltd.
[1732] Mancuso, S., C. Taiti, N. Bazihizina, C. Costa, P. Menesatti, L. Giagnoni, M. Arenella, P. Nannipieri, and G. Renella, "Soil volatile analysis by proton transfer reaction-time of flight mass spectrometry (PTR-TOF-{MS})", Applied Soil Ecology, vol. 86, pp. 182¬タモ191, Feb, 2015.
Link: http://dx.doi.org/10.1016/j.apsoil.2014.10.018
Abstract
<p>We analyzed the volatile organic compounds (VOCs) emitted from different soils by using the PTR-MS-TOF technique under laboratory conditions and compared them with soil chemical biochemical activities. The emitted VOCs were related to soil microbial biomass, soil respiration and some soil enzyme activities so as to evaluate if size and activity of soil microbial communities influenced the soil VOCs profiles. Our results showed that the emitted VOCs discriminated between soils with different properties and management, and differences in the VOCs emission profiles were likely related to the active metabolic pathways in the microbial communities of the three studied soil. Our results also showed that some soil enzyme activities such as β-glucosidase and arylsulfatase were possibly involved in the release of compounds fueling microbial metabolic pathways leading to the production of specific VOCs. It was concluded that the PTR-MS-TOF technique is suitable for analyze VOCs emission from soil and that studies comparing soil enzyme activities and soil volatile profiles can reveal the origin of VOCs and give further insights on microbial activity and soil functionality.</p>
2014
[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
2013
[Beauchamp2013] Beauchamp, JD., and JD. Pleil, "Simply breath-taking? Developing a strategy for consistent breath sampling", Journal of Breath Research, vol. 7, no. 4: IOP Publishing, pp. 042001, 2013.
Link: http://iopscience.iop.org/1752-7163/7/4/042001
[Schuhfried2013] Schuhfried, E., M. Probst, J. Limtrakul, S. Wannakao, E. Aprea, L. Cappellin, T. D. Märk, F. Gasperi, and F. Biasioli, "Sulfides: chemical ionization induced fragmentation studied with proton transfer reaction-mass spectrometry and density functional calculations.", J Mass Spectrom, vol. 48, no. 3: Institut für Ionenphysik und Angewandte Physik, Leopold Franzens Universität Innsbruck, Technikerstr. 25, A-6020, Innsbruck, Austria., pp. 367–378, Mar, 2013.
Link: http://dx.doi.org/10.1002/jms.3153
Abstract
We report the energy-dependent fragmentation patterns upon protonation of eight sulfides (organosulfur compounds) in Proton Transfer Reaction-Mass Spectrometry (PTR-MS). Studies were carried out, both, experimentally with PTR-MS, and with theoretical quantum-chemical methods. Charge retention usually occurred at the sulfur-containing fragment for short chain sulfides. An exception to this is found in the unsaturated monosulfide allylmethyl sulfide (AMS), which preferentially fragmented to a carbo-cation at m/z 41, C3H5(+). Quantum chemical calculations (DFT with the M062X functional 6-31G(d,p) basis sets) for the fragmentation reaction pathways of AMS indicated that the most stable protonated AMS cation at m/z 89 is a protonated (cyclic) thiirane, and that the fragmentation reaction pathways of AMS in the drift tube are kinetically controlled. The protonated parent ion MH(+) is the predominant product in PTR-MS, except for diethyl disulfide at high collisional energies. The saturated monosulfides R-S-R' (with R<R') have little or no fragmentation, at the same time the most abundant fragment ion is the smaller R-S(+) fragment. The saturated disulfides R-S-S-R display more fragmentation than the saturated monosulfides, the most common fragments are disulfide containing fragments or long-chain carbo-cations. The results rationalize fragmentation data for saturated monosulfides and disulfides and represent a detailed analysis of the fragmentation of an unsaturated sulfide. Apart from the theoretical interest, the results are in support of the quantitative analysis of sulfides with PTR-MS, all the more so as PTR-MS is one of a few techniques that allow for ultra-low quantitative analysis of sulfides.
2012
[1511] Fares, S.., J.-H.. Park, D.. R. Gentner, R.. Weber, E.. Ormeᅢᄆo, J.. Karlik, and A.. H. Goldstein, "Seasonal cycles of biogenic volatile organic compound fluxes and concentrations in a California citrus orchard", Atmospheric Chemistry and Physics, vol. 12, pp. 9865–9880, Oct, 2012.
Link: http://dx.doi.org/10.5194/acp-12-9865-2012
Abstract
<p>Orange trees are widely cultivated in Mediterranean climatic regions where they are an important agricultural crop. Citrus have been characterized as emitters of volatile organic compounds (VOC) in chamber studies under controlled environmental conditions, but an extensive characterization at field scale has never been performed using modern measurement methods, and is particularly needed considering the complex interactions between the orchards and the polluted atmosphere in which Citrus is often cultivated. For one year, in a Valencia orange orchard in Exeter, California, we measured fluxes using PTRMS (Proton Transfer Reaction Mass Spectrometer) and eddy covariance for the most abundant VOC typically emitted from citrus vegetation: methanol, acetone, and isoprenoids. Concentration gradients of additional oxygenated and aromatic compounds from the ground level to above the canopy were also measured. In order to characterize concentrations of speciated biogenic VOC (BVOC) in leaves, we analyzed leaf content by GC-MS (Gas Chromatography &ndash; Mass Spectrometery) regularly throughout the year. We also characterized in more detail concentrations of speciated BVOC in the air above the orchard by in-situ GC-MS during a few weeks in spring flowering and summer periods. Here we report concentrations and fluxes of the main VOC species emitted by the orchard, discuss how fluxes measured in the field relate to previous studies made with plant enclosures, and describe how VOC content in leaves and emissions change during the year in response to phenological and environmental parameters. The orchard was a source of monoterpenes and oxygenated VOC. The highest emissions were observed during the springtime flowering period, with mid-day fluxes above 2 nmol m&minus;2 s&minus;1 for methanol and up to 1 nmol m&minus;2 s&minus;1 for acetone and monoterpenes. During hot summer days emissions were not as high as we expected considering the known dependence of biogenic emissions on temperature. We provide evidence that thickening of leaf cuticle wax content limited gaseous emissions during the summer.</p>
[Karl2012] Karl, T., A. Hansel, L. Cappellin, L. Kaser, I. Herdlinger-Blatt, and W. Jud, "Selective measurements of isoprene and 2-methyl-3-buten-2-ol based on NO+ ionization mass spectrometry", Atmospheric Chemistry and Physics, vol. 12, no. 24: Copernicus GmbH, pp. 11877–11884, 2012.
Link: http://www.atmos-chem-phys.net/12/11877/2012/acp-12-11877-2012.html
Abstract
Biogenic VOC emissions are often dominated by 2-methyl-1,3-butadiene (isoprene) and 2-methyl-3-buten-2-ol (232 MBO). Here we explore the possibility to selectively distinguish these species using NO+ as a primary ion in a conventional PTR-MS equipped with an SRI unit. High purity of NO+ (>90%) as a primary ion was utilized in laboratory and field experiments using a conventional PTR-TOF-MS. Isoprene is ionized via charge transfer leading to the major product ion C5H8+ (>99%) (e.g. Spanel and Smith, 1998). 232 MBO undergoes a hydroxide ion transfer reaction resulting in the major product ion channel C5H9+ (>95%) (e.g. Amelynck et al., 2005). We show that both compounds are ionized with little fragmentation (>5%) under standard operating conditions. Typical sensitivities of 11.1 ± 0.1 (isoprene) and 12.9 ± 0.1 (232 MBO) ncps ppbv−1 were achieved, which correspond to limit of detections of 18 and 15 pptv respectively for a 10 s integration time. Sensitivities decreased at higher collisional energies. Calibration experiments showed little humidity dependence. We tested the setup at a field site in Colorado dominated by ponderosa pine, a 232 MBO emitting plant species. Our measurements confirm 232 MBO as the dominant biogenic VOC at this site, exhibiting typical average daytime concentrations between 0.2–1.4 ppbv. The method is able to detect the presence of trace levels of isoprene at this field site (90–250 ppt) without any interference from 232 MBO, which would not be feasible using H3O+ ionization chemistry, and which currently also remains a challenge for other analytical techniques (e.g. gas chromatographic methods).
[Nolscher2012] Nölscher, AC., J. Williams, V. Sinha, T. Custer, W. Song, AM. Johnson, R. Axinte, H. Bozem, H. Fischer, N. Pouvesle, et al., "Summertime total OH reactivity measurements from boreal forest during HUMPPA-COPEC 2010", Atmospheric Chemistry and Physics, vol. 12, no. 17: Copernicus GmbH, pp. 8257–8270, 2012.
Link: http://www.atmos-chem-phys.net/12/8257/2012/acp-12-8257-2012.html
Abstract
Ambient total OH reactivity was measured at the Finnish boreal forest station SMEAR II in Hyytiälä (Latitude 61°51' N; Longitude 24°17' E) in July and August 2010 using the Comparative Reactivity Method (CRM). The CRM – total OH reactivity method – is a direct, in-situ determination of the total loss rate of hydroxyl radicals (OH) caused by all reactive species in air. During the intensive field campaign HUMPPA-COPEC 2010 (Hyytiälä United Measurements of Photochemistry and Particles in Air – Comprehensive Organic Precursor Emission and Concentration study) the total OH reactivity was monitored both inside (18 m) and directly above the forest canopy (24 m) for the first time. The comparison between these two total OH reactivity measurements, absolute values and the temporal variation have been analyzed here. Stable boundary layer conditions during night and turbulent mixing in the daytime induced low and high short-term variability, respectively. The impact on total OH reactivity from biogenic emissions and associated photochemical products was measured under "normal" and "stressed" (i.e. prolonged high temperature) conditions. The advection of biomass burning emissions to the site caused a marked change in the total OH reactivity vertical profile. By comparing the OH reactivity contribution from individually measured compounds and the directly measured total OH reactivity, the size of any unaccounted for or "missing" sink can be deduced for various atmospheric influences. For "normal" boreal conditions a missing OH reactivity of 58%, whereas for "stressed" boreal conditions a missing OH reactivity of 89% was determined. Various sources of not quantified OH reactive species are proposed as possible explanation for the high missing OH reactivity.
2011
[Cristescu2011] Cristescu, S.. M., H.. A. Gietema, L.. Blanchet, C. L. J. J. Kruitwagen, P.. Munnik, R.. J. { van Klaveren}, J. W. J. Lammers, L.. Buydens, F. J. M. Harren, and P.. Zanen, "Screening for emphysema via exhaled volatile organic compounds.", J Breath Res, vol. 5, no. 4: Life Science Trace Gas Facility, Molecular and Laser Physics, Institute for Molecules and Materials, Radboud University, Nijmegen, the Netherlands. simona@science.ru.nl, pp. 046009, Dec, 2011.
Link: http://dx.doi.org/10.1088/1752-7155/5/4/046009
Abstract
Chronic obstructive pulmonary disease (COPD)/emphysema risk groups are well defined and screening allows for early identification of disease. The capability of exhaled volatile organic compounds (VOCs) to detect emphysema, as found by computed tomography (CT) in current and former heavy smokers participating in a lung cancer screening trial, was investigated. CT scans, pulmonary function tests and breath sample collections were obtained from 204 subjects. Breath samples were analyzed with a proton-transfer reaction mass spectrometer (PTR-MS) to obtain VOC profiles listed as ions at various mass-to-charge ratios (m/z). Using bootstrapped stepwise forward logistic regression, we identified specific breath profiles as a potential tool for the diagnosis of emphysema, of airflow limitation or gas-exchange impairment. A marker for emphysema was found at m/z 87 (tentatively attributed to 2-methylbutanal). The area under the receiver operating characteristic curve (ROC) of this marker to diagnose emphysema was 0.588 (95% CI 0.453-0.662). Mass-to-charge ratios m/z 52 (most likely chloramine) and m/z 135 (alkyl benzene) were linked to obstructive disease and m/z 122 (most probably alkyl homologs) to an impaired diffusion capacity. ROC areas were 0.646 (95% CI 0.562-0.730) and 0.671 (95% CI 0.524-0.710), respectively. In the screening setting, exhaled VOCs measured by PTR-MS constitute weak markers for emphysema, pulmonary obstruction and impaired diffusion capacity.
[1622] Millet, D.. B., M.. J. Mohr, K.. C. Wells, T.. J. Griffis, and D.. Helmig, "Sources and seasonality of atmospheric methanol based on tall tower measurements in the US Upper Midwest", Atmospheric Chemistry and Physics, vol. 11, pp. 11145–11156, 2011.
Link: http://dx.doi.org/10.5194/acp-11-11145-2011
Abstract
We present over one year (January 2010–February 2011) of continuous atmospheric methanol measurements from the University of Minnesota tall tower Trace Gas Observatory (KCMP tall tower; 244 m a.g.l.), and interpret the dataset in terms of constraints on regional methanol sources and seasonality. The seasonal cycle of methanol concentrations observed at the KCMP tall tower is generally similar to that simulated by a global 3-D chemical transport model (GEOS-Chem, driven with MEGANv2.0 biogenic emissions) except the seasonal peak occurs  1 month earlier in the observations, apparently reflecting a model underestimate of emission rates for younger versus older leaves. Based on a source tracer approach, which we evaluate using GEOS-Chem and with multiple tracers, we estimate that anthropogenic emissions account for approximately 40% of ambient methanol abundance during winter and 10% during summer. During daytime in summer, methanol concentrations increase exponentially with temperature, reflecting the temperature sensitivity of the biogenic source, and the observed temperature dependence is statistically consistent with that in the model. Nevertheless, summertime concentrations are underestimated by on average 35% in the model for this region. The seasonal importance of methanol as a source of formaldehyde (HCHO) and carbon monoxide (CO) is highest in spring through early summer, when biogenic methanol emissions are high but isoprene emissions are still relatively low. During that time observed methanol concentrations account for on average 20% of the total CO and HCHO production rates as simulated by GEOS-Chem, compared to 12% later in the summer and 12% on an annual average basis. The biased seasonality in the model means that the photochemical role for methanol early in the growing season is presently underestimated.
[Juerschik2011] Juerschik, S., P. Sulzer, A. Jordan, L. Maerk, and M. D Tilmann, "Sprengstoffe und Drogen–PTR-MS in der Spurenanalytik", Nachrichten aus der Chemie, vol. 59, no. 11, pp. 1087–1088, 2011.
Link: http://www.degruyter.com/view/j/nachrchem.2011.59.11/nachrchem.2011.59.11.1087/nachrchem.2011.59.11.1087.xml
[Hansen2011] Hansen, M. J., A. P. S. Adamsen, A. Feilberg, and K. E. N. Jonassen, "Stability of odorants from pig production in sampling bags for olfactometry", Journal of environmental quality, vol. 40, no. 4: The American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc., pp. 1096–1102, 2011.
Link: https://dl.sciencesocieties.org/publications/jeq/abstracts/40/4/1096
Abstract
Odor from pig production facilities is typically measured with olfactometry, whereby odor samples are collected in sampling bags and assessed by human panelists within 30 h. In the present study, the storage stability of odorants in two types of sampling bags that are often used for olfactometry was investigated. The bags were made of Tedlar or Nalophan. In a field experiment, humid and dried air samples were collected from a pig production facility with growing-finishing pigs and analyzed with a gas chromatograph with an amperometric sulfur detector at 4, 8, 12, 28, 52, and 76 h after sampling. In a laboratory experiment, the bags were filled with a humid gas mixture containing carboxylic acids, phenols, indoles, and sulfur compounds and analyzed with proton-transfer-reaction mass spectrometry after 0, 4, 8, 12, and 24 h. The results demonstrated that the concentrations of carboxylic acids, phenols, and indoles decreased by 50 to >99% during the 24 h of storage in Tedlar and Nalophan bags. The concentration of hydrogen sulfide decreased by approximately 30% during the 24 h of storage in Nalophan bags, whereas in Tedlar bags the concentration of sulfur compounds decreased by <5%. In conclusion, the concentrations of odorants in air samples from pig production facilities significantly decrease during storage in Tedlar and Nalophan bags, and the composition changes toward a higher relative presence of sulfur compounds. This can result in underestimation of odor emissions from pig production facilities and of the effect of odor reduction technologies.
[Williams2011] Williams, J., J. Crowley, H. Fischer, H. Harder, M. Martinez, T. Petäjä, J. Rinne, J. Bäck, M. Boy, M. Dal Maso, et al., "The summertime Boreal forest field measurement intensive (HUMPPA-COPEC-2010): an overview of meteorological and chemical influences", Atmospheric Chemistry and Physics Discussions, vol. 11, no. 5: Copernicus GmbH, pp. 15921–15973, 2011.
Link: http://www.atmos-chem-phys-discuss.net/11/15921/2011/acpd-11-15921-2011.html
Abstract
This paper describes the background, instrumentation, goals, and the regional influences on the HUMPPA-COPEC intensive field measurement campaign, conducted at the Boreal forest research station SMEAR II (Station for Measuring Ecosystem-Atmosphere Relation) in Hyytiälä, Finland from 12 July–12 August 2010. The prevailing meteorological conditions during the campaign are examined and contrasted with those of the past six years. Back trajectory analyses show that meteorological conditions at the site were characterized by a higher proportion of southerly flow. As a result the summer of 2010 was anomalously warm and high in ozone making the campaign relevant for the analysis of possible future climates. A comprehensive land use analysis, provided on both 5 and 50 km scales, shows that the main vegetation types surrounding the site on both the regional and local scales are: coniferous forest (Scots pine and/or Norway spruce); mixed forest (Birch and conifers); and woodland scrub (e.g. Willows, Aspen); indicating that the campaign results can be taken as representative of the Boreal forest ecosystem. In addition to the influence of biogenic emissions, the measurement site was occasionally impacted by sources other than vegetation. Specific tracers have been used here to identify the time periods when such sources have impacted the site namely: biomass burning (acetonitrile and CO), urban anthropogenic pollution (pentane and SO2) and the nearby Korkeakoski sawmill (enantiomeric ratio of chiral monoterpenes). None of these sources dominated the study period, allowing the Boreal forest summertime emissions to be assessed and contrasted with various other source signatures.
2010
[Kai2010] Kai, M., E. Crespo, S. M. Cristescu, F. J. M. Harren, W. Francke, and B. Piechulla, "Serratia odorifera: analysis of volatile emission and biological impact of volatile compounds on Arabidopsis thaliana.", Appl Microbiol Biotechnol, vol. 88, no. 4: Department of Biological Sciences, University of Rostock, Albert-Einstein-Str. 3, 18059 Rostock, Germany., pp. 965–976, Oct, 2010.
Link: http://dx.doi.org/10.1007/s00253-010-2810-1
Abstract
Bacteria emit a wealth of volatiles. The combination of coupled gas chromatography/mass spectrometry (GC/MS) and proton-transfer-reaction mass spectrometry (PTR-MS) analyses provided a most comprehensive profile of volatiles of the rhizobacterium Serratia odorifera 4Rx13. An array of compounds, highly dominated by sodorifen (approximately 50%), a bicyclic oligomethyl octadiene, could be detected. Other volatiles included components of the biogeochemical sulfur cycle such as dimethyl disulfide (DMDS), dimethyl trisulfide and methanethiol, terpenoids, 2-phenylethanol, and other aromatic compounds. The composition of the bouquet of S. odorifera did not change significantly during the different growth intervals. At the beginning of the stationary phase, 60 ?g of volatiles per 24 h and 60 easily detectable components were released. Ammonia was also released by S. odorifera, while ethylene, nitric oxide (NO) and hydrogen cyanide (HCN) could not be detected. Dual culture assays proved that 20 ?mol DMDS and 2.5 ?mol ammonia, individually applied, represent the IC(50) concentrations that cause negative effects on Arabidopsis thaliana.
[Yeretzian2010] Yeretzian, C., A. Glöss, S. Petrozzi, L. D'Ambrosio, K. Knöpfli-Lengweiler, F. Wieland, A. Fridolin Wild, and R. Anliker, "The smell of coffee–an analytical perspective", , 2010.
Link: http://www.icbc.zhaw.ch/fileadmin/user_upload/life_sciences/_Institute_und_Zentren/icbc/Weiterbildung/CAS_Coffee/Medien/2010/2010-09-01-GC-MS.pdf
Abstract
Within the last century, coffee has become one of the world’s most popular beverages and represents a major economic factor for many coffee-producing countries and a significant business sector in consuming countries. The success of this fascinating brew has been overwhelming and its future seems even more exciting1,2. The ever transforming landscape of coffee-shops and coffee-houses, the various trends and fads in the growing speciality coffee sector, the mounting awareness about origins, the steady innovations in the coffee machine sector and last but not least, the rising media-hype around the Barista-scene are all just the tip of the iceberg for a steadily growing coffee-lover community and an astonishingly recession-resistant industry
[Hansen2010] Hansen, M. Jørgen, A. Feilberg, and A. Peter S. Adamsen, "Stability of volatile reduced sulphur compounds in the dilution system of an olfactometer", Chem. Eng. Trans, vol. 23, pp. 67–72, 2010.
Link: http://www.aidic.it/cet/10/23/012.pdf
[Seewald2010] Seewald, M. S. A., W. Singer, B. A. Knapp, I. H. Franke-Whittle, A. Hansel, and H. Insam, "Substrate-induced volatile organic compound emissions from compost-amended soils", Biology and Fertility of Soils, vol. 46: Springer-Verlag, pp. 371-382, 2010.
Link: http://dx.doi.org/10.1007/s00374-010-0445-0
Abstract
The agronomic effects of composts, mineral fertiliser and combinations thereof on chemical, biological and physiological soil properties have been studied in an 18-year field experiment. The present study aimed at tracing treatment effects by evaluating the volatile organic compound (VOC) emission of the differently treated soils: non-amended control, nitrogen fertilisation and composts (produced from organic waste and sewage sludge, respectively) in combination with nitrogen fertiliser. Microbial community structure was determined by denaturing gradient gel electrophoresis (DGGE). Aerobic and anaerobic soil VOC emission was determined after glucose amendment using proton transfer reaction–mass spectrometry (PTR-MS). After inducing VOC production by substrate (glucose) addition and at the same time reducing oxygen availability to impair degradation of the produced VOCs, we were able to differentiate among the treatments. Organic waste compost did not alter the VOC emissions compared to the untreated control, whilst sewage sludge composts and mineral fertilisation showed distinct effects. This differentiation was supported by DGGE analysis of fungal 18S rDNA fragments and confirms earlier findings on bacterial communities. Three major conclusions can be drawn: (1) VOC patterns are able to discriminate among soil treatments. (2) Sewage sludge compost and mineral fertilisation have not only the strongest impact on microbial community composition but also on VOC emission patterns, but specific tracer VOCs could not be identified. (3) Future efforts should aim at a PTR-MS-linked identification of the detected masses.
2009
[Lauverjat2009] Lauverjat, C. mentine, I. De le ris, I. Cristian T. le a, C. Salles, and I. Souchon, "Salt and aroma compound release in model cheeses in relation to their mobility", Journal of agricultural and food chemistry, vol. 57, no. 21: ACS Publications, pp. 9878–9887, 2009.
Link: http://pubs.acs.org/doi/abs/10.1021/jf901446w
Abstract
Physicochemical properties (partition and diffusion coefficients) involved in the mobility and release of salt and aroma compounds in model cheeses were determined in this study. The values of NaCl water/product partition coefficients highlighted interactions between proteins and NaCl. However, these interactions were not modified by the product composition or structure. On the contrary, model cheese composition and structure influenced NaCl diffusion and both partition and diffusion for aroma compounds. Analysis of in-nose measurements of aroma release during eating, with regard to physicochemical properties, showed that product and aroma properties partly contributed to flavor release. Depending on the model cheese composition, structure and firmness, physicochemical properties, food breakdown, and chewing behavior can lead to different aroma release profiles. Finally, a discussion of all the results with regard to salt and flavor perception of the model cheese showed that both physicochemical and cognitive mechanisms contributed to perception.

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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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