A compact PTR-ToF-MS instrument for airborne measurements of volatile organic compounds at high spatiotemporal resolution

Müller, Markus; Mikoviny, Tomáš; Feil, S.; Haidacher, S.; Hanel, G.; Hartungen, Eugen; Jordan, Alfons; Märk, Lukas; Mutschlechner, Paul; Schottkowsky, R.; Sulzer, Philipp; Crawford, J. H.; Wisthaler, Armin

doi:10.5194/amt-7-3763-2014

Cited by 118 publications

(117 citation statements)

References 17 publications

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“…VOC background signals in the instrument were determined by passing ambient air through a catalytic converter. The detection limits are compound-dependent and range between 10 and 100 ppt for most VOC species at a time resolution of 1 s. Besides VOCs, two inorganic species, NH 3 and H 2 S, were measured at m/z 18.034 (NH + 4 ) and m/z 34.995 (H 3 S + ) using the H 3 O + ToF-CIMS, respectively (Li et al, 2014;Müller et al, 2014).…”

Section: Methodsmentioning

confidence: 99%

Emissions of volatile organic compounds (VOCs) from concentrated animal feeding operations (CAFOs): chemical compositions and separation of sources

et al. 2017

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Abstract. Concentrated animal feeding operations (CAFOs) emit a large number of volatile organic compounds (VOCs) to the atmosphere. In this study, we conducted mobile laboratory measurements of VOCs, methane (CH 4 ) and ammonia (NH 3 ) downwind of dairy cattle, beef cattle, sheep and chicken CAFO facilities in northeastern Colorado using a hydronium ion time-of-flight chemical-ionization mass spectrometer (H 3 O + ToF-CIMS), which can detect numerous VOCs. Regional measurements of CAFO emissions in northeastern Colorado were also performed using the NOAA WP-3D aircraft during the Shale Oil and Natural Gas Nexus (SONGNEX) campaign. Alcohols and carboxylic acids dominate VOC concentrations and the reactivity of the VOCs with hydroxyl (OH) radicals. Sulfur-containing and phenolic species provide the largest contributions to the odor activity values and the nitrate radical (NO 3 ) reactivity of VOC emissions, respectively. VOC compositions determined from mobile laboratory and aircraft measurements generally agree well with each other. The high timeresolution mobile measurements allow for the separation of the sources of VOCs from different parts of the operations occurring within the facilities. We show that the emissions of ethanol are primarily associated with feed storage and handling. Based on mobile laboratory measurements, we apply a multivariate regression analysis using NH 3 and ethanol as tracers to determine the relative importance of animalrelated emissions (animal exhalation and waste) and feedrelated emissions (feed storage and handling) for different VOC species. Feed storage and handling contribute significantly to emissions of alcohols, carbonyls, carboxylic acids and sulfur-containing species. Emissions of phenolic species and nitrogen-containing species are predominantly associated with animals and their waste.

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Section: Methodsmentioning

confidence: 99%

Emissions of volatile organic compounds (VOCs) from concentrated animal feeding operations (CAFOs): chemical compositions and separation of sources

et al. 2017

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“…This work focuses on NMOGs as measured by the PTR-ToF-MS instrument described in detail by Müller et al (2014). The data presented herein were acquired at a frequency of 10 Hz, which makes the PTR-ToF-MS instrument ideally suited for airborne NMOG measurements at high spatiotemporal resolution.…”

Section: Analytical Instrumentationmentioning

confidence: 99%

“…Accurate m/z information; element restriction to C, H, N, and O atoms; and isotopic pattern analyses were used to determine the elemental composition (C w H x N y O z ) of detected analyte ions. It has been shown in previous work that accurate m/z information can be obtained even at a moderate mass resolution m/ m in the range of 1000 to 1500 (Müller et al, 2011(Müller et al, , 2014. The assignment of observed m/z signals to specific chemical compounds was based on the literature (see Sect.…”

Section: Analytical Instrumentationmentioning

confidence: 99%

In situ measurements and modeling of reactive trace gases in a small biomass burning plume

et al. 2016

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Abstract. An instrumented NASA P-3B aircraft was used for airborne sampling of trace gases in a plume that had emanated from a small forest understory fire in Georgia, USA. The plume was sampled at its origin to derive emission factors and followed ∼ 13.6 km downwind to observe chemical changes during the first hour of atmospheric aging. The P-3B payload included a proton-transfer-reaction timeof-flight mass spectrometer (PTR-ToF-MS), which measured non-methane organic gases (NMOGs) at unprecedented spatiotemporal resolution (10 m spatial / 0.1 s temporal). Quantitative emission data are reported for CO 2 , CO, NO, NO 2 , HONO, NH 3 , and 16 NMOGs (formaldehyde, methanol, acetonitrile, propene, acetaldehyde, formic acid, acetone plus its isomer propanal, acetic acid plus its isomer glycolaldehyde, furan, isoprene plus isomeric pentadienes and cyclopentene, methyl vinyl ketone plus its isomers crotonaldehyde and methacrolein, methylglyoxal, hydroxy acetone plus its isomers methyl acetate and propionic acid, benzene, 2,3-butanedione, and 2-furfural) with molar emission ratios relative to CO larger than 1 ppbV ppmV −1 . Formaldehyde, acetaldehyde, 2-furfural, and methanol dominated NMOG emissions. No NMOGs with more than 10 carbon atoms were observed at mixing ratios larger than 50 pptV ppmV −1 CO. Downwind plume chemistry was investigated using the observations and a 0-D photochemical box model simulation. The model was run on a nearly explicit chemical mechanism (MCM v3.3) and initialized with measured emission data. Ozone formation during the first hour of atmospheric aging was well captured by the model, with carbonyls (formaldehyde, acetaldehyde, 2,3-butanedione, methylglyoxal, 2-furfural) in addition to CO and CH 4 being the main drivers of peroxy radical chemistry. The model also accurately reproduced the sequestration of NO x into peroxyacetyl nitrate (PAN) and the OH-initiated degradation of furan and 2-furfural at an average OH concentration of 7.45 ± 1.07 × 10 6 cm −3 in the plume. Formaldehyde, acetone/propanal, acetic acid/glycolaldehyde, and maleic acid/maleic anhydride (tentatively identified) were found to be the main NMOGs to increase during 1 h of atmospheric plume processing, with the model being unable to capture the observed increase. A mass balance analysis suggests that about 50 % of the aerosol mass formed in the downwind plume is organic in nature.

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“…In the Profile 3 (Instrument Science, Crewe, UK) SIFT-MS instrument 15 the drive pump thus represents almost half of the weight of the instrument and in Voice 200 (Syft Technologies Ltd. Christchurch, New Zealand) an even larger drive pump is used. In PTR-MS, smaller drive pumps are required 3 . Nevertheless, disadvantages of both PTR-MS and SIFT-MS instruments, as currently available, are their size, weight and cost, which inhibit wider application.…”

mentioning

confidence: 99%

“…Furthermore, size, weight and cost of instrumentation are important issues and versatility is very desirable for research applications when a great variety of VOCs need to be detected and analysed. [3][4][5] In this regard, gas chromatography with mass spectrometry, GC-MS, has made a major contribution to gas analysis, but it is not a real time technique. Whilst nanomaterial-based sensors, 6 laser spectroscopic techniques 7 and ion mobility spectrometry, IMS, 8 are partly a solution for real time analysis, there is a need for further development of techniques based on chemical ionization during defined reaction times, exemplified by selected ion flow tube mass spectrometry, SIFT-MS, 1 and proton transfer reaction mass spectrometry, PTR-MS. 2,9,10 Both of these techniques are widely used for real time trace gas analysis in various areas and are able to accurately quantify trace compounds and biomarkers in air and exhaled breath.…”

mentioning

confidence: 99%

Selected Ion Flow-Drift Tube Mass Spectrometry: Quantification of Volatile Compounds in Air and Breath

2015

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A selected ion flow drift tube mass spectrometric analytical technique, SIFDT-MS, is described that extends the established selected ion flow tube mass spectrometry, SIFT-MS, by the inclusion of a static but variable E-field along the axis of the flow tube reactor in which the analytical ion-molecule chemistry occurs. The ion axial speed is increased in proportion to the reduced field strength E/N (N is the carrier gas number density) and the residence/reaction time, t, which is measured by Hadamard transform multiplexing, is correspondingly reduced. To ensure a proper understanding of the physics and ion chemistry underlying SIFDT-MS, ion diffusive loss to the walls of the flow-drift tube and the mobility of injected H3O+ ions have been studied as a function of E/N. It is seen that the derived diffusion coefficient and mobility of H3O + ions are consistent with those previously reported. The rate coefficient has been determined at elevated E/N for the association reaction of the H3O + reagent ions with H2O molecules, which is the first step in the production of H3O + (H2O)1,2,3 reagent hydrate ions. The production of hydrated analyte ion was also experimentally investigated. The analytical performance of SIFDT-MS is demonstrated by the quantification of acetone and isoprene in exhaled breath. Finally, the essential features of SIFDT-MS and SIFT-MS are compared, notably pointing out that a much lower speed of the flow-drive pump is required for SIFDT-MS, which facilitates development of smaller cost-effective analytical instruments for real time breath and fluid headspace analyses.

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A compact PTR-ToF-MS instrument for airborne measurements of volatile organic compounds at high spatiotemporal resolution

Cited by 118 publications

References 17 publications

Emissions of volatile organic compounds (VOCs) from concentrated animal feeding operations (CAFOs): chemical compositions and separation of sources

Emissions of volatile organic compounds (VOCs) from concentrated animal feeding operations (CAFOs): chemical compositions and separation of sources

In situ measurements and modeling of reactive trace gases in a small biomass burning plume

Selected Ion Flow-Drift Tube Mass Spectrometry: Quantification of Volatile Compounds in Air and Breath

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