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Scientific Articles - PTR-MS Bibliography

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Found 47 results
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A
[Sprung2001] Sprung, D., C. Jost, T. Reiner, A. Hansel, and A. Wisthaler, "Acetone and acetonitrile in the tropical Indian Ocean boundary layer and free troposphere: Aircraft-based intercomparison of AP-CIMS and PTR-MS measurements", Journal of Geophysical Research: Atmospheres (1984–2012), vol. 106, no. D22: Wiley Online Library, pp. 28511–28527, 2001.
Link: http://onlinelibrary.wiley.com/doi/10.1029/2000JD900599/full
[Warneke1999] Warneke, C., T. Karl, H. Judmaier, A. Hansel, A. Jordan, W. Lindinger, and P. J. Crutzen, "Acetone, methanol, and other partially oxidized volatile organic emissions from dead plant matter by abiological processes: Significance for atmospheric HOx chemistry", Global Biogeochem. Cycles, vol. 13, no. 1, pp. 9–17, 1999.
Link: http://onlinelibrary.wiley.com/doi/10.1029/98GB02428/full
[Taucher1996] Taucher, J., A. Hansel, A. Jordan, and W. Lindinger, "Analysis of compounds in human breath after ingestion of garlic using proton-transfer-reaction mass spectrometry", Journal of agricultural and food chemistry, vol. 44, no. 12: ACS Publications, pp. 3778–3782, 1996.
Link: http://pubs.acs.org/doi/abs/10.1021/jf960640e
Abstract
After ingestion of raw garlic, the components allyl methyl sulfide (1), allyl methyl disulfide (2), diallyl sulfide (3), diallyl disulfide (4), diallyl trisulfide (7), dimethyl sulfide (8), and acetone (9) in the breath of a test person were analyzed over a time period of about 30 h by means of proton-transfer-reaction mass spectrometry. While the concentrations of 2−7 reached maxima shortly after ingestion of garlic and declined to baseline values within the next 2−3 h, concentrations of 1, 8, and 9 increased much more slowly and showed enhanced values even 30 h after garlic consumption. The strong increase of the concentration of acetone might be indicative of enhanced metabolism of serum cholesterol, triglycerides, and total lipids in the blood stream.
[Singer2011] Singer, W., J. Herbig, R. Gutmann, K. Winkler, I. Kohl, and A. Hansel, "Applications of PTR-MS in medicine and biotechnology", American Laboratory, vol. 43, no. 7: AMER LABORATORY-LABCOMPARE 30 CONTROLS DRIVE, SHELTON, CT 06484 USA, pp. 34–37, 2011.
Link: http://www.americanlaboratory.com/913-Technical-Articles/19001-Applications-of-PTR-MS-in-Medicine-and-Biotechnology/
Abstract
Proton transfer reaction-mass spectrometry (PTR-MS) is a well-established analytical tool for the measurement of volatile organic compounds (VOCs), and offers real-time detection and quantification of VOCs at trace concentrations. This paper focuses on the measurement of VOCs in biological systems. Both microorganisms and cells, e.g., in the human body, constantly produce a large variety of volatile organic metabolites. Analyzing VOCs in exhaled human breath reveals information about the status of the body. In a similar manner, monitoring the off-gas of fermentations in the biopharmaceutical industry allows microbial activity to be gauged. Undesired compounds (those that are harmful to the human body or impurities in biotechnical processes) can also be tracked in real time using the technique.
[DAnna2005] D'Anna, B., A. Wisthaler, Øyvind. Andreasen, A. Hansel, J. Hjorth, N. R. Jensen, C. J. Nielsen, Y. Stenstrøm, and J. Viidanoja, "Atmospheric chemistry of C3-C6 cycloalkanecarbaldehydes.", J Phys Chem A, vol. 109, no. 23: Department of Chemistry, University of Oslo, P.O. Box 1033 Blindern, N-0315 Oslo, Norway. barbara.danna@kjemi.uio.no, pp. 5104–5118, Jun, 2005.
Link: http://dx.doi.org/10.1021/jp044495g
Abstract
The rate coefficients for the gas phase reaction of NO3 and OH radicals with a series of cycloalkanecarbaldehydes have been measured in purified air at 298 +/- 2 K and 760 +/- 10 Torr by the relative rate method using a static reactor equipped with long-path Fourier transform infrared (FT-IR) detection. The values obtained for the OH radical reactions (in units of 10(-11) cm3 molecule(-1) s(-1)) were the following: cyclopropanecarbaldehyde, 2.13 +/- 0.05; cyclobutanecarbaldehyde, 2.66 +/- 0.06; cyclopentanecarbaldehyde, 3.27 +/- 0.07; cyclohexanecarbaldehyde, 3.75 +/- 0.05. The values obtained for the NO3 radical reactions (in units of 10(-14) cm3 molecule(-1) s(-1)) were the following: cyclopropanecarbaldehyde, 0.61 +/- 0.04; cyclobutanecarbaldehyde, 1.99 +/- 0.06; cyclopentanecarbaldehyde, 2.55 +/- 0.10; cyclohexanecarbaldehyde, 3.19 +/- 0.12. Furthermore, the reaction products with OH radicals have been investigated using long-path FT-IR spectroscopy and proton-transfer-reaction mass spectrometry (PTR-MS). The measured carbon balances were in the range 89-97%, and the identified products cover a wide spectrum of compounds including nitroperoxycarbonyl cycloalkanes, cycloketones, cycloalkyl nitrates, multifunctional compounds containing carbonyl, hydroxy, and nitrooxy functional groups, HCOOH, HCHO, CO, and CO2.
[Holzinger2001a] Holzinger, R., A. Jordan, A. Hansel, and W. Lindinger, "Automobile emissions of acetonitrile: Assessment of its contribution to the global source", Journal of atmospheric chemistry, vol. 38, no. 2: Springer, pp. 187–193, 2001.
Link: http://www.springerlink.com/index/g3rn0j32865r9220.pdf
B
[Mueller2006] Müller, K., S. Haferkorn, W. Grabmer, A. Wisthaler, A. Hansel, J. Kreuzwieser, C. Cojocariu, H. Rennenberg, and H. Herrmann, "Biogenic carbonyl compounds within and above a coniferous forest in Germany", Atmospheric Environment, vol. 40: Elsevier, pp. 81–91, 2006.
Link: http://www.sciencedirect.com/science/article/pii/S1352231006003220
Abstract
Diurnal mixing ratios of aldehydes and ketones were investigated during two joint experiments in summer months to identify biogenic contributions from coniferous forests to tropospheric chemistry. In a Norway spruce forest, the diurnal variation of carbonyl compounds was measured at 12 m (in the treetop) and at 24 m (above the canopy). The main findings of the experiment are that acetone (up to 9.1 ppbv), formaldehyde (up to 6.5 ppbv), acetaldehyde (up to 5.5 ppbv) and methyl ethyl ketone (MEK, up to 1.8 ppbv) were found in highest concentrations. For all major compounds with the exception of MEK, primary emissions are supposed. From α-pinene oxidation, pinonaldehyde was found with its peak concentrations (up to 0.15 ppbv) during the early morning hours. The diurnal variation of concentrations for most other compounds shows maximum concentrations near midday in 2,4-dinitrophenylhydrazine (DNPH) measurements but not for proton-transfer reaction mass spectrometry (PTR-MS) measurements of acetaldehyde and acetone. A clear correlation of carbonyl compound concentration to the radiation intensity and the temperature (R2=0.66) was found. However, formaldehyde did not show distinct diurnal variations. A very high correlation was observed for both heights between mixing ratios of acetaldehyde and acetone (R2=0.84), acetone and MEK (R2=0.90) as well as acetaldehyde and MEK (R2=0.88) but not for formaldehyde and the others. For the most time, the observed carbonyl compound concentrations above the canopy are higher than within the forest stand. This indicates an additional secondary formation in the atmosphere above the forest. The differences of acetone and acetaldehyde mixing ratios detected by DNPH technique and the PTR-MS could not be fully clarified by a laboratory intercomparison.
[Holzinger1999] Holzinger, R., C. Warneke, A. Hansel, A. Jordan, W. Lindinger, D. H. Scharffe, G. Schade, and P. J. Crutzen, "Biomass burning as a source of formaldehyde, acetaldehyde, methanol, acetone, acetonitrile, and hydrogen cyanide", Geophysical Research Letters, vol. 26, no. 8: Wiley Online Library, pp. 1161–1164, 1999.
Link: http://onlinelibrary.wiley.com/doi/10.1029/1999GL900156/full
[1587] Hörtnagl, L., I. Bamberger, M. Graus, T. M. Ruuskanen, R. Schnitzhofer, M. Müller, A. Hansel, and G. Wohlfahrt, "Biotic, abiotic and management controls on methanol exchange above a temperate mountain grassland.", J Geophys Res Biogeosci, vol. 116, Sep, 2011.
Link: http://dx.doi.org/10.1029/2011jg001641
Abstract
<p>Methanol (CH3OH) fluxes were quantified above a managed temperate mountain grassland in the Stubai Valley (Tyrol, Austria) during the growing seasons 2008 and 2009. Half-hourly methanol fluxes were calculated by means of the virtual disjunct eddy covariance (vDEC) method using 3-dimensional wind data from a sonic anemometer and methanol volume mixing ratios measured with a proton-transfer-reaction mass spectrometer (PTR-MS). During (undisturbed) mature and growing phases methanol fluxes exhibited a clear diurnal cycle with close-to-zero fluxes during nighttime and emissions, up to 10 nmol m(-2) s(-1), which followed the diurnal course of radiation and air temperature. Management events were found to represent the largest perturbations of methanol exchange at the studied grassland ecosystem: Peak emissions of 144.5 nmol m(-2) s(-1) were found during/after cutting of the meadow reflecting the wounding of the plant material and subsequent depletion of the leaf internal aqueous methanol pools. After the application of organic fertilizer, elevated methanol emissions of up to 26.7 nmol m(-2) s(-1) were observed, likely reflecting enhanced microbial activity associated with the applied manure. Simple and multiple linear regression analyses revealed air temperature and radiation as the dominant abiotic controls, jointly explaining 47 % and 70 % of the variability in half-hourly and daily methanol fluxes. In contrast to published leaf-level laboratory studies, the surface conductance and the daily change in the amount of green plant area, used as ecosystem-scale proxies for stomatal conductance and growth, respectively, were found to exert only minor biotic controls on methanol exchange.</p>
[Herbig2008] Herbig, J., T. Titzmann, J. Beauchamp, I. Kohl, and A. Hansel, "Buffered end-tidal (BET) sampling-a novel method for real-time breath-gas analysis.", J Breath Res, vol. 2, no. 3: Ionimed Analytik GmbH, Technikerstrasse 21a, A-6020 Innsbruck, Austria., pp. 037008, Sep, 2008.
Link: http://iopscience.iop.org/1752-7163/2/3/037008/
Abstract
We present a novel method for real-time breath-gas analysis using mass-spectrometric techniques: buffered end-tidal (BET) on-line sampling. BET has several advantages over conventional direct on-line sampling where the subject inhales and exhales through a sampling tube. In our approach, a single exhalation is administered through a tailored tube in which the end-tidal fraction of the breath-gas sample is buffered. This increases sampling time by an order of magnitude to several seconds, improving signal quality and reducing the total measurement time per test subject. Furthermore, only one exhalation per minute is required for sampling and the test subject can otherwise maintain a normal breathing pattern, thereby reducing the risk of hyperventilation. To validate our new BET sampling method we conducted comparative measurements with direct on-line sampling using proton-transfer-reaction mass spectrometry. We find excellent agreement in measured acetone and acetonitrile concentrations. High variability observed in breath-by-breath isoprene concentrations is attributed to differences in exhalation depth and influences of hyperventilation on end-tidal concentrations.
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[Schnitzler2004] SCHNITZLER, JÖRG-PETER., M. Graus, J. Kreuzwieser, U. Heizmann, H. Rennenberg, A. Wisthaler, and A. Hansel, "Contribution of different carbon sources to isoprene biosynthesis in poplar leaves", Plant Physiology, vol. 135, no. 1: Am Soc Plant Biol, pp. 152–160, 2004.
Link: http://www.plantphysiol.org/content/135/1/152.short
Abstract
This study was performed to test if alternative carbon sources besides recently photosynthetically fixed CO2 are used for isoprene formation in the leaves of young poplar (Populus × canescens) trees. In a 13CO2 atmosphere under steady state conditions, only about 75% of isoprene became 13C labeled within minutes. A considerable part of the unlabeled carbon may be derived from xylem transported carbohydrates, as may be shown by feeding leaves with [U-13C]Glc. As a consequence of this treatment approximately 8% to 10% of the carbon emitted as isoprene was 13C labeled. In order to identify further carbon sources, poplar leaves were depleted of leaf internal carbon pools and the carbon pools were refilled with 13C labeled carbon by exposure to 13CO2. Results from this treatment showed that about 30% of isoprene carbon became 13C labeled, clearly suggesting that, in addition to xylem transported carbon and CO2, leaf internal carbon pools, e.g. starch, are used for isoprene formation. This use was even increased when net assimilation was reduced, for example by abscisic acid application. The data provide clear evidence of a dynamic exchange of carbon between different cellular precursors for isoprene biosynthesis, and an increasing importance of these alternative carbon pools under conditions of limited photosynthesis. Feeding [1,2-13C]Glc and [3-13C]Glc to leaves via the xylem suggested that alternative carbon sources are probably derived from cytosolic pyruvate/phosphoenolpyruvate equivalents and incorporated into isoprene according to the predicted cleavage of the 3-C position of pyruvate during the initial step of the plastidic deoxyxylulose-5-phosphate pathway.
D
[1584] Hörtnagl, L., R. Clement, M. Graus, A. Hammerle, A. Hansel, and G. Wohlfahrt, "Dealing with disjunct concentration measurements in eddy covariance applications: a comparison of available approaches.", Atmos Environ (1994), vol. 44, May, 2010.
Link: http://www.sciencedirect.com/science/article/pii/S1352231010001810
Abstract
<p>Using proton transfer reaction mass spectrometry equipped with a quadrupol mass analyser to quantify the biosphere-atmosphere exchange of volatile organic compounds (VOC), concentrations of different VOC are measured sequentially. Depending on how many VOC species are targeted and their respective integration times, each VOC is measured at repeat rates on the order of a few seconds. This represents an order of magnitude longer sample interval compared to the standard eddy covariance (EC) method (5-20 Hz sampling rates). Here we simulate the effect of disjunct sampling on EC flux estimates by decreasing the time resolution of CO2 and H2O concentrations measured at 20 Hz above a temperate mountain grassland in the Austrian Alps. Fluxes for one month are calculated with the standard EC method and compared to fluxes calculated based on the disjunct data (1, 3 and 5 s sampling rates) using the following approaches: i) imputation of missing concentrations based on the nearest neighbouring samples (iDECnn), ii) imputation by linear interpolation (iDECli), and iii) virtual disjunct EC (vDEC), i.e. flux calculation based solely on the disjunct concentrations. It is shown that the two imputation methods result in additional low-pass filtering, longer lag times (as determined with the maximum cross-correlation method) and a flux loss of 3-30 % as compared to the standard EC method. A novel procedure, based on a transfer function approach, which specifically corrects for the effect of data treatment, was developed, resulting in improved correspondence (to within 2 %). The vDEC method yields fluxes which approximate the true (20 Hz) fluxes to within 3-7 % and it is this approach we recommend because it involves no additional empirical corrections. The only drawback of the vDEC method is the noisy nature of the cross-correlations, which poses problems with lag determination - practical approaches to overcome this limitation are discussed.</p>
[Brilli2011] Brilli, F., T. M. Ruuskanen, R. Schnitzhofer, M. Müller, M. Breitenlechner, V. Bittner, G. Wohlfahrt, F. Loreto, and A. Hansel, "Detection of plant volatiles after leaf wounding and darkening by proton transfer reaction "time-of-flight" mass spectrometry (PTR-TOF).", PLoS One, vol. 6, no. 5: Ionicon Analytik G.m.b.H., Innsbruck, Austria., pp. e20419, 2011.
Link: http://dx.doi.org/10.1371/journal.pone.0020419
Abstract
Proton transfer reaction-time of flight (PTR-TOF) mass spectrometry was used to improve detection of biogenic volatiles organic compounds (BVOCs) induced by leaf wounding and darkening. PTR-TOF measurements unambiguously captured the kinetic of the large emissions of green leaf volatiles (GLVs) and acetaldehyde after wounding and darkening. GLVs emission correlated with the extent of wounding, thus confirming to be an excellent indicator of mechanical damage. Transient emissions of methanol, C5 compounds and isoprene from plant species that do not emit isoprene constitutively were also detected after wounding. In the strong isoprene-emitter Populus alba, light-dependent isoprene emission was sustained and even enhanced for hours after photosynthesis inhibition due to leaf cutting. Thus isoprene emission can uncouple from photosynthesis and may occur even after cutting leaves or branches, e.g., by agricultural practices or because of abiotic and biotic stresses. This observation may have important implications for assessments of isoprene sources and budget in the atmosphere, and consequences for tropospheric chemistry.
[Mielke2008] Mielke, L. H., D. E. Erickson, S. A. McLuckey, M. Müller, A. Wisthaler, A. Hansel, and P. B. Shepson, "Development of a proton-transfer reaction-linear ion trap mass spectrometer for quantitative determination of volatile organic compounds.", Anal Chem, vol. 80, no. 21: Department of Chemistry, Purdue University, 860 Oval Drive West, Lafayette, Indiana 47907-2084, USA., pp. 8171–8177, Nov, 2008.
Link: http://dx.doi.org/10.1021/ac801328d
Abstract
Currently, proton-transfer reaction mass spectrometry (PTR-MS) allows for quantitative determination of volatile organic compounds in real time at concentrations in the low ppt range, but cannot differentiate isomers or isobaric molecules, using the conventional quadrupole mass filter. Here we pursue the application of linear quadrupole ion trap (LIT) mass spectrometry in combination with proton-transfer reaction chemical ionization to provide the advantages of specificity from MS/MS. A commercial PTR-MS platform composed of a quadrupole mass filter with the addition of end cap electrodes enabled the mass filter to operate as a linear ion trap. The rf drive electronics were adapted to enable the application of dipolar excitation to opposing rods, for collision-induced dissociation (CID) of trapped ions. This adaptation enabled ion isolation, ion activation, and mass analysis. The utility of the PTR-LIT was demonstrated by distinguishing between the isomeric isoprene oxidation pair, methyl vinyl ketone (MVK) and methacrolein (MACR). The CID voltage was adjusted to maximize the m/ z 41 to 43 fragment ratio of MACR while still maintaining adequate sensitivity. Linear calibration curves for MVK and MACR fragments at m/ z 41 and 43 were obtained with limits of detection of approximately 100 ppt, which should enable ambient measurements. Finally, the PTR-LIT method was compared to an established GC/MS method by quantifying MVK and MACR production during a smog chamber isoprene-NO x irradiation experiment.
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[Tani2004] Tani, A., S. Hayward, A. Hansel, and N. C Hewitt, "Effect of water vapour pressure on monoterpene measurements using proton transfer reaction-mass spectrometry (PTR-MS)", International Journal of Mass Spectrometry, vol. 239, no. 2: Elsevier, pp. 161–169, 2004.
Link: http://www.sciencedirect.com/science/article/pii/S1387380604003495
Abstract
The effects of water vapour pressure (WVP) on the fragmentation of seven monoterpene and related C10 volatile organic compounds (VOCs) in the drift tube of a proton transfer reaction-mass spectrometer (PTR-MS) were investigated. In addition, the combined effects of varying WVP and the ratios of electric field strength to number density of the buffer gas (E/N) were investigated in detail for three of these compounds, the monoterpenes α-pinene and sabinene plus the related C10 VOC p-cymene. Under normal operating conditions (E/N = 124 Td), WVP affected the fragment patterns of all compounds with the exception of β-pinene and the three oxygenated C10 VOCs. WVP had a significant effect on the fragment patterns of α-pinene and sabinene at the lower E/N ratios (around 80 Td) but had little effect on fragmentation towards the higher E/N ratios used here (∼142 Td). On the other hand, p-cymene fragmentation was most affected by WVP under normal operating conditions. PTR-MS sensitivity towards the three compounds was also considered under three conditions where reaction was assumed with (1) H3O+ only; (2) H3O+ and H3O+H2O; and (3) H3O+, H3O+H2O and H3O+(H2O)2. Our results indicate that α-pinene and sabinene react not only with H3O+ and H3O+H2O via direct proton transfer but also with H3O+(H2O)2 via ligand switching. p-Cymene seems to react only with H3O+ via direct proton transfer and with H3O+H2O via ligand switching. It is speculated that the WVP effect on fragmentation results from the differing abundances of hydrated reagent ions which causes different frequencies of individual reactions to occur, thus, determining how ‘soft’ the overall reaction is. These results also indicate that under normal conditions, a correction should be made for WVP if the concentration of p-cymene in air samples is to be determined from the single ion signal of either protonated molecular ions or the most dominant fragment ions.
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[Kohl2013b] Kohl, I., J. Beauchamp, F. Cakar-Beck, J. Herbig, J.. Dunkl, O. Tietje, M. Tiefenthaler, C. Boesmueller, A. Wisthaler, M. Breitenlechner, et al., "First observation of a potential non-invasive breath gas biomarker for kidney function.", J Breath Res, vol. 7, no. 1: Ionimed Analytik GmbH, Eduard Bodem Gasse 3, A-6020 Innsbruck, Austria., pp. 017110, Mar, 2013.
Link: http://dx.doi.org/10.1088/1752-7155/7/1/017110
Abstract
We report on the search for low molecular weight molecules-possibly accumulated in the bloodstream and body-in the exhaled breath of uremic patients with kidney malfunction. We performed non-invasive analysis of the breath gas of 96 patients shortly before and several times after kidney transplantation using proton-transfer-reaction mass spectrometry (PTR-MS), a very sensitive technique for detecting trace amounts of volatile organic compounds. A total of 642 individual breath analyses which included at least 41 different chemical components were carried out. Correlation analysis revealed one particular breath component with a molecular mass of 114 u (unified atomic mass units) that clearly correlated with blood serum creatinine, which is the currently accepted marker for assessing the function of the kidney. In particular, daily urine production showed good correlation with the identified breath marker. An independent set of seven samples taken from three patients at the onset of dialysis and three controls with normal kidney function confirmed a significant difference in concentration between patients and controls for a compound with a molecular mass of 114.1035 u using high mass resolving proton-transfer-reaction time-of-flight mass spectrometry (PTR-TOF-MS). A chemical composition of CHO was derived for the respective component. Fragmentation experiments on the same samples using proton-transfer-reaction triple-quadrupole tandem mass spectrometry (PTR-QqQ-MS) suggested that this breath marker is a C-ketone or a branched C-aldehyde. Non-invasive real-time monitoring of the kidney function via this breath marker could be a possible future procedure in the clinical setting.
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[Jacob2005] Jacob, D. J., B. D. Field, Q. Li, D. R. Blake, J. de Gouw, C. Warneke, A. Hansel, A. Wisthaler, H. B. Singh, and A. Guenther, "Global budget of methanol: Constraints from atmospheric observations", Journal of Geophysical Research: Atmospheres (1984–2012), vol. 110, no. D8: Wiley Online Library, 2005.
Link: http://onlinelibrary.wiley.com/doi/10.1029/2004JD005172/full
Abstract
We use a global three-dimensional model simulation of atmospheric methanol to examine the consistency between observed atmospheric concentrations and current understanding of sources and sinks. Global sources in the model include 128 Tg yr−1 from plant growth, 38 Tg yr−1 from atmospheric reactions of CH3O2 with itself and other organic peroxy radicals, 23 Tg yr−1 from plant decay, 13 Tg yr−1 from biomass burning and biofuels, and 4 Tg yr−1 from vehicles and industry. The plant growth source is a factor of 3 higher for young than from mature leaves. The atmospheric lifetime of methanol in the model is 7 days; gas-phase oxidation by OH accounts for 63% of the global sink, dry deposition to land 26%, wet deposition 6%, uptake by the ocean 5%, and aqueous-phase oxidation in clouds less than 1%. The resulting simulation of atmospheric concentrations is generally unbiased in the Northern Hemisphere and reproduces the observed correlations of methanol with acetone, HCN, and CO in Asian outflow. Accounting for decreasing emission from leaves as they age is necessary to reproduce the observed seasonal variation of methanol concentrations at northern midlatitudes. The main model discrepancy is over the South Pacific, where simulated concentrations are a factor of 2 too low. Atmospheric production from the CH3O2 self-reaction is the dominant model source in this region. A factor of 2 increase in this source (to 50–100 Tg yr−1) would largely correct the discrepancy and appears consistent with independent constraints on CH3O2 concentrations. Our resulting best estimate of the global source of methanol is 240 Tg yr−1. More observations of methanol concentrations and fluxes are needed over tropical continents. Better knowledge is needed of CH3O2 concentrations in the remote troposphere and of the underlying organic chemistry.
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[Graus2010] Graus, M., M. Müller, and A. Hansel, "High resolution PTR-TOF: quantification and formula confirmation of VOC in real time.", J Am Soc Mass Spectrom, vol. 21, no. 6: University of Innsbruck, Institute of Ion Physics and Applied Physics, Innsbruck, Austria., pp. 1037–1044, Jun, 2010.
Link: http://dx.doi.org/10.1016/j.jasms.2010.02.006
Abstract
We present the unprecedented capability to identify and quantify volatile organic compounds (VOCs) by means of proton transfer reaction time-of-flight (PTR-TOF) mass spectrometry on-line with high time resolution. A mass resolving power of 4000-5000 and a mass accuracy of 2.5 ppm allow for the unambiguous sum-formula identification of hydrocarbons (HCs) and oxygenated VOCs (OVOCs). Test masses measured over an 11-wk period are very precise (SD < 3.4 ppm) and the mass resolving power shows good stability (SD < 5%). Based on a 1 min time resolution, we demonstrate a detection limit in the low pptv range featuring a dynamic range of six orders of magnitude. Sub-ppbv VOC concentrations are analyzed within a second; sub-pptv detection limits are achieved within a few tens of minutes. We present a thorough characterization of our recently developed PTR-TOF system and address application fields for the new instrument.
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[Luchner2012] Luchner, M., R. Gutmann, K. Bayer, J. Dunkl, A. Hansel, J. Herbig, W. Singer, F. Strobl, K. Winkler, and G. Striedner, "Implementation of proton transfer reaction-mass spectrometry (PTR-MS) for advanced bioprocess monitoring.", Biotechnol Bioeng, vol. 109, no. 12: ACIB GmbH, Muthgasse 11, A-1190 Vienna, Austria., pp. 3059–3069, Dec, 2012.
Link: http://dx.doi.org/10.1002/bit.24579
Abstract
We report on the implementation of proton transfer reaction-mass spectrometry (PTR-MS) technology for on-line monitoring of volatile organic compounds (VOCs) in the off-gas of bioreactors. The main part of the work was focused on the development of an interface between the bioreactor and an analyzer suitable for continuous sampling of VOCs emanating from the bioprocess. The permanently heated sampling line with an inert surface avoids condensation and interaction of volatiles during transfer to the PTR-MS. The interface is equipped with a sterile sinter filter unit directly connected to the bioreactor headspace, a condensate trap, and a series of valves allowing for dilution of the headspace gas, in-process calibration, and multiport operation. To assess the aptitude of the entire system, a case study was conducted comprising three identical cultivations with a recombinant E. coli strain, and the volatiles produced in the course of the experiments were monitored with the PTR-MS. The high reproducibility of the measurements proved that the established sampling interface allows for reproducible transfer of volatiles from the headspace to the PTR-MS analyzer. The set of volatile compounds monitored comprises metabolites of different pathways with diverse functions in cell physiology but also volatiles from the process matrix. The trends of individual compounds showed diverse patterns. The recorded signal levels covered a dynamic range of more than five orders of magnitude. It was possible to assign specific volatile compounds to distinctive events in the bioprocess. The presented results clearly show that PTR-MS was successfully implemented as a powerful bioprocess-monitoring tool and that access to volatiles emitted by the cells opens promising perspectives in terms of advanced process control.
[Boshier2009] Boshier, P., O. Priest, J. Herbig, G. Hanna, and N. Marczin, "Influence of respiratory manoeuvres on the 'on-line' detection of volatile organic compounds (VOCs) in exhaled by hs-PTR-MS", CONFERENCE SERIES, pp. 230, 2009.
Link: http://www.ionicon.com/sites/default/files/uploads/doc/contributions_ptr_ms_Conference_4.pdf
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[Fischer2013a] Fischer, L., A. Klinger, J. Herbig, K. Winkler, R. Gutmann, and A. Hansel, "The LCU: Versatile Trace Gas Calibration", 6th International PTR-MS Conference on Proton Transfer Reaction Mass Spectrometry and Its Applications, pp. 192, 2013.
Link: http://www.ionicon.com/sites/default/files/uploads/doc/contributions_ptr_ms_Conference_6.pdf
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[Holzinger2001] Holzinger, R., A. Jordan, A. Hansel, and W. Lindinger, "Methanol measurements in the lower troposphere near Innsbruck (047° 16 N; 011° 24 E), Austria", Atmospheric Environment, vol. 35, no. 14: Elsevier, pp. 2525–2532, 2001.
Link: http://www.sciencedirect.com/science/article/pii/S1352231000004301
[Hansel2000] Hansel, A., and A. Wisthaler, "A method for real-time detection of PAN, PPN and MPAN in ambient air", Geophysical research letters, vol. 27, no. 6: Wiley Online Library, pp. 895–898, 2000.
Link: http://onlinelibrary.wiley.com/doi/10.1029/1999GL010989/full
[Mayrhofer2006] Mayrhofer, S., T. Mikoviny, S. Waldhuber, A. O. Wagner, G. Innerebner, I. H. Franke-Whittle, T. D. Maerk, A. Hansel, and H. Insam, "Microbial community related to volatile organic compound (VOC) emission in household biowaste.", Environ Microbiol, vol. 8, no. 11: Institut fuer Mikrobiologie, Universitaet Innsbruck, Innsbruck, Austria. sabine.mayrhofer@uibk.ac.at, pp. 1960–1974, Nov, 2006.
Link: http://dx.doi.org/10.1111/j.1462-2920.2006.01076.x
Abstract
Malodorous emissions and potentially pathogenic microorganisms which develop during domestic organic waste collection are not only a nuisance but may also pose health risks. The aim of the present study was to determine whether the presence of specific microorganisms in biowastes is directly related to the composition of the emitted volatile organic compounds (VOCs). The succession of microbial communities during 16 days of storage in organic waste collection bins was studied by denaturing gradient gel electrophoresis (DGGE) of amplified 16S ribosomal DNA in parallel with a classical cultivation and isolation approach. Approximately 60 different bacterial species and 20 different fungal species were isolated. Additionally, some bacterial species were identified through sequencing of excised DGGE bands. Proton transfer reaction mass spectrometry (PTR-MS) was used to detect VOCs over the sampling periods, and co-inertia analyses of VOC concentrations with DGGE band intensities were conducted. Positive correlations, indicating production of the respective VOC or enhancement of microbial growth, and negative correlations, indicating the use of, or microbial inhibition by the respective compound, were found for the different VOCs. Measurement of the VOC emission pattern from a pure culture of Lactococcus lactis confirmed the positive correlations for the protonated masses 89 (tentatively identified as butyric acid), 63 (tentatively identified as dimethylsulfide), 69 (likely isoprene) and 73 (likely butanone).
[Fischer2013] Fischer, L., V. Ruzsanyi, K. Winkler, R. Gutmann, A. Hansel, and J. Herbig, "Micro-Capillary-Column PTR-TOF", 6th International PTR-MS Conference on Proton Transfer Reaction Mass Spectrometry and Its Applications, pp. 162, 2013.
Link: http://www.ionicon.com/sites/default/files/uploads/doc/contributions_ptr_ms_Conference_6.pdf

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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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