scholarly journals Production of highly oxygenated organic molecules (HOMs) from trace contaminants during isoprene oxidation

2018 ◽  
Author(s):  
Anne-Kathrin Bernhammer ◽  
Lukas Fischer ◽  
Bernhard Mentler ◽  
Martin Heinritzi ◽  
Mario Simon ◽  
...  
Keyword(s):  
Reaction Time ◽  
Organic Molecules ◽  
Transfer Reaction ◽  
Proton Transfer Reaction ◽  
Reaction Chamber ◽  
Diels Alder ◽  
Cloud Chamber ◽  
Secondary Association ◽  
Main Fragment ◽  
Isoprene Oxidation

Abstract. During nucleation studies from pure isoprene oxidation in the CLOUD chamber at CERN we observed unexpected ion signals at m/z = 137.133 (C10H17+) and m/z = 81.070 (C6H9+) with the recently developed proton transfer reaction time-of-flight mass spectrometer (PTR3‑TOF) instrument. The mass-to-charge ratios of these ion signals typically correspond to protonated monoterpenes and their main fragment. We identified two origins of these signals: First secondary association reactions of protonated isoprene with isoprene within the PTR3 reaction chamber and secondly [4+2] cycloaddition (Diels-Alder) of isoprene inside the gas bottle which presumably forms the favoured monoterpenes limonene and sylvestrene, as known from literature. Under our PTR3 conditions used in 2016 an amount (relative to isoprene) of 2 % is formed within the PTR3 reaction chamber and 1 % is already present in the gas bottle. The presence of unwanted cycloaddition products in the CLOUD chamber impacts the nucleation studies by creating ozonolysis products as corresponding monoterpenes, and is responsible for the majority of the observed highly oxygenated organic molecules (HOMs). In order to study NPF from pure isoprene oxidation under atmospheric relevant conditions, it is important to improve and assure the quality and purity of the precursor isoprene. This was successfully achieved by cryogenically trapping lower volatility compounds such as monoterpenes before isoprene was introduced into the CLOUD chamber.

scholarly journals Production of highly oxygenated organic molecules (HOMs) from trace contaminants during isoprene oxidation

2018 ◽  
Vol 11 (8) ◽  
pp. 4763-4773 ◽  
Author(s):  
Anne-Kathrin Bernhammer ◽  
Lukas Fischer ◽  
Bernhard Mentler ◽  
Martin Heinritzi ◽  
Mario Simon ◽  
...  
Keyword(s):  
Organic Molecules ◽  
Nuclear Research ◽  
Proton Transfer Reaction ◽  
Reaction Chamber ◽  
Diels Alder ◽  
Cloud Chamber ◽  
Atmospheric Conditions ◽  
European Organization ◽  
Main Fragment ◽  
Isoprene Oxidation

Abstract. During nucleation studies from pure isoprene oxidation in the CLOUD chamber at the European Organization for Nuclear Research (CERN) we observed unexpected ion signals at m∕z = 137.133 (C10H17+) and m∕z = 81.070 (C6H9+) with the recently developed proton-transfer-reaction time-of-flight (PTR3-TOF) mass spectrometer instrument. The mass-to-charge ratios of these ion signals typically correspond to protonated monoterpenes and their main fragment. We identified two origins of these signals: first secondary association reactions of protonated isoprene with isoprene within the PTR3-TOF reaction chamber and secondly [4+2] cycloaddition (Diels–Alder) of isoprene inside the gas bottle which presumably forms the favored monoterpenes limonene and sylvestrene, as known from literature. Under our PTR3-TOF conditions used in 2016 an amount (relative to isoprene) of 2 % is formed within the PTR3-TOF reaction chamber and 1 % is already present in the gas bottle. The presence of unwanted cycloaddition products in the CLOUD chamber impacts the nucleation studies by creating ozonolysis products as the corresponding monoterpenes and is responsible for the majority of the observed highly oxygenated organic molecules (HOMs), which in turn leads to a significant overestimation of both the nucleation rate and the growth rate. In order to study new particle formation (NPF) from pure isoprene oxidation under relevant atmospheric conditions, it is important to improve and assure the quality and purity of the precursor isoprene. This was successfully achieved by cryogenically trapping lower-volatility compounds such as monoterpenes before isoprene was introduced into the CLOUD chamber.

scholarly journals Characterization of gas-phase organics using proton transfer reaction time-of-flight mass spectrometry: fresh and aged residential wood combustion emissions

2016 ◽  
Author(s):  
Emily A. Bruns ◽  
Jay G. Slowik ◽  
Imad El Haddad ◽  
Dogushan Kilic ◽  
Felix Klein ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Reaction Time ◽  
Biomass Burning ◽  
Transfer Reaction ◽  
Proton Transfer Reaction ◽  
Wood Combustion ◽  
Flight Mass Spectrometry ◽  
Combustion Emissions ◽  
Organic Gases

Abstract. Organic gases emitted during the flaming phase of residential wood combustion are characterized individually and by functionality using proton transfer reaction time-of-flight mass spectrometry. The evolution of the organic gases is monitored during photochemical aging. Primary gaseous emissions are dominated by oxygenated species (e.g., acetic acid, acetaldehyde, phenol and methanol), many of which have deleterious health effects and play an important role in atmospheric processes such as secondary organic aerosol formation and ozone production. Residential wood combustion emissions differ considerably from open biomass burning in both absolute magnitude and relative composition. Ratios of acetonitrile, a potential biomass burning marker, to CO are considerably lower (~ 0.09 pptv ppbv−1) than those observed in air masses influenced by open burning (~ 1–2 pptv ppbv−1), which may make differentiation from background levels difficult, even in regions heavily impacted by residential wood burning. Considerable formic acid forms during aging (~ 200–600 mg kg−1 at an OH exposure of (4.5–5.5) × 107 molec  cm−3 h), indicating residential wood combustion can be an important local source for this acid, the quantities of which are currently underestimated in models. Phthalic anhydride, a naphthalene oxidation product, is also formed in considerable quantities with aging (~ 55–75 mg kg−1 at an OH exposure of (4.5–5.5) × 107 molec  cm−3 h). Although total NMOG emissions vary by up to a factor of ~ 9 between burns, SOA formation potential does not scale with total NMOG emissions and is similar in all experiments. This study is the first thorough characterization of both primary and aged organic gases from residential wood combustion and provides a benchmark for comparison of emissions generated under different burn parameters.

scholarly journals Detection of Plant Volatiles after Leaf Wounding and Darkening by Proton Transfer Reaction “Time-of-Flight” Mass Spectrometry (PTR-TOF)

PLoS ONE ◽  
2011 ◽  
Vol 6 (5) ◽  
pp. e20419 ◽  
Author(s):  
Federico Brilli ◽  
Taina M. Ruuskanen ◽  
Ralf Schnitzhofer ◽  
Markus Müller ◽  
Martin Breitenlechner ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Reaction Time ◽  
Proton Transfer ◽  
Plant Volatiles ◽  
Transfer Reaction ◽  
Time Of Flight ◽  
Proton Transfer Reaction ◽  
Flight Mass Spectrometry

scholarly journals Characterization of biomass burning smoke from cooking fires, peat, crop residue and other fuels with high resolution proton-transfer-reaction time-of-flight mass spectrometry

2014 ◽  
Vol 14 (15) ◽  
pp. 22163-22216 ◽  
Author(s):  
C. E. Stockwell ◽  
P. R. Veres ◽  
J. Williams ◽  
R. J. Yokelson
Keyword(s):  
Reaction Time ◽  
High Resolution ◽  
Proton Transfer ◽  
Organic Compounds ◽  
Biomass Burning ◽  
Crop Residue ◽  
Transfer Reaction ◽  
Time Of Flight ◽  
Proton Transfer Reaction ◽  
Tof Ms

Abstract. We deployed a high-resolution proton-transfer-reaction time-of-flight mass spectrometer (PTR-TOF-MS) to measure biomass burning emissions from peat, crop-residue, cooking fires, and many other fire types during the fourth Fire Lab at Missoula Experiment (FLAME-4) laboratory campaign. A combination of gas standards calibrations and composition sensitive, mass dependent calibration curves were applied to quantify gas-phase non-methane organic compounds (NMOCs) observed in the complex mixture of fire emissions. We used several approaches to assign best identities to most major "exact masses" including many high molecular mass species. Using these methods approximately 80–96% of the total NMOC mass detected by PTR-TOF-MS and FTIR was positively or tentatively identified for major fuel types. We report data for many rarely measured or previously unmeasured emissions in several compound classes including aromatic hydrocarbons, phenolic compounds, and furans; many of which are suspected secondary organic aerosol precursors. A large set of new emission factors (EFs) for a range of globally significant biomass fuels is presented. Measurements show that oxygenated NMOCs accounted for the largest fraction of emissions of all compound classes. In a brief study of various traditional and advanced cooking methods, the EFs for these emissions groups were greatest for open 3-stone cooking in comparison to their more advanced counterparts. Several little-studied nitrogen-containing organic compounds were detected from many fuel types that together accounted for 0.1–8.7% of the fuel nitrogen and some may play a role in new particle formation.

scholarly journals Eddy covariance emission and deposition flux measurements using proton transfer reaction-time of flight-mass spectrometry (PTR-TOF-MS): comparison with PTR-MS measured vertical gradients and fluxes

2012 ◽  
Vol 12 (8) ◽  
pp. 20435-20482 ◽  
Author(s):  
J.-H. Park ◽  
A. H. Goldstein ◽  
J. Timkovsky ◽  
S. Fares ◽  
R. Weber ◽  
...  
Keyword(s):  
Reaction Time ◽  
Proton Transfer ◽  
Organic Compounds ◽  
Transfer Reaction ◽  
Vertical Gradient ◽  
Proton Transfer Reaction ◽  
Volatile Organic ◽  
Flux Measurements ◽  
Ion Species ◽  
Tof Ms

Abstract. During summer 2010, a proton transfer reaction-time of flight-mass spectrometer (PTR-TOF-MS) and a standard proton transfer reaction mass spectrometer (PTR-MS) were deployed simultaneously for one month in an orange orchard in the Central Valley of California to collect continuous data suitable for eddy covariance (EC) flux calculations. The high time resolution (5 Hz) and high mass resolution (up to 5000 m Δ m−1) data from the PTR-TOF-MS provided the basis for calculating the concentration and flux for a wide range of volatile organic compounds (VOC). Throughout the campaign, 664 mass peaks were detected in mass-to-charge ratios between 10 and 1278. Here we present PTR-TOF-MS EC fluxes of the 27 ion species for which the vertical gradient was simultaneously measured by PTR-MS. These EC flux data were validated through spectral analysis (i.e. co-spectrum, normalized co-spectrum, and ogive). Based on inter-comparison of the two PTR instruments, no significant instrumental biases were found in either mixing ratios or fluxes, and the data showed agreement within 5% on average for methanol and acetone. For the measured biogenic volatile organic compounds (BVOC), the EC fluxes from PTR-TOF-MS were in agreement with the qualitatively inferred flux directions from vertical gradient measurements by PTR-MS. For the 27 selected ion species reported here, the PTR-TOF-MS measured total (24 h) mean net flux of 299 μg C m−2 h−1. The dominant BVOC emissions from this site were monoterpenes (m/z 81.070 + m/z 137.131 + m/z 95.086, 34%, 102 μg C m−2 h−1) and methanol (m/z 33.032, 18%, 72 μg C m−2 h−1). The next largest fluxes were detected at the following masses (attribution in parenthesis): m/z 59.048 (mostly acetone, 12.2%, 36.5 μg C m−2 h−1), m/z 61.027 (mostly acetic acid, 11.9%, 35.7 μg C m−2 h−1), m/z 93.069 (para-cymene + toluene, 4.1%, 12.2 μg C m−2 h−1), m/z 45.033 (acetaldehyde, 3.8%, 11.5 μg C m−2 h−1), m/z 71.048 (methylvinylketone + methacrolein, 2.4%, 7.1 μg C m−2 h−1), and m/z 69.071 (isoprene + 2-methyl-3-butene-2-ol, 1.8%, 5.3 μg C m−2 h−1). Low levels of emission and/or deposition (<1.6% for each, 5.8% in total flux) were observed for the additional reported masses. Overall, our results show that EC flux measurements using PTR-TOF-MS is a powerful new tool for characterizing the biosphere-atmosphere exchange including both emission and deposition for a large range of BVOC and their oxidation products.

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