Interference in the PTR-MS measurement of acetonitrile at m/z 42 in polluted urban air—A study using switchable reagent ion PTR-MS

Dunne, Erin; Galbally, Ian E.; Lawson, Sarah; Patti, Antonio F.

doi:10.1016/j.ijms.2012.05.004

Cited by 29 publications

(32 citation statements)

References 17 publications

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“…Interference in the identification and quantification of a target compound in PTR-MS measurements of ambient air can and frequently does occur due to the presence of products from other reaction pathways such as isobaric compounds, fragment ions from other compounds, isotopologues and products of secondary reactions Rogers et al, 2006;Inomata et al, 2008;Dunne et al, 2012;Kaser et al, 2013). When comparing PTR-MS measurements to more selective VOC measurement techniques such as chromatographic methods, the presence of interference in the target ion signal often results in an apparent positive bias in the PTR-MS reported values.…”

Section: Proton-transfer-reaction Mass Spectrometry (Ptr-ms)mentioning

confidence: 99%

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Comparison of VOC measurements made by PTR-MS, adsorbent tubes–GC-FID-MS and DNPH derivatization–HPLC during the Sydney Particle Study, 2012: a contribution to the assessment of uncertainty in routine atmospheric VOC measurements

et al. 2018

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Abstract. Understanding uncertainty is essential for utilizing atmospheric volatile organic compound (VOC) measurements in robust ways to develop atmospheric science. This study describes an inter-comparison of the VOC data, and the derived uncertainty estimates, measured with three independent techniques (PTR-MS, proton-transfer-reaction mass spectrometry; GC-FID-MS, gas chromatography with flameionization and mass spectrometric detection; and DNPH-HPLC, 2,4-dinitrophenylhydrazine derivatization followed by analysis by high-performance liquid chromatography) during routine monitoring as part of the Sydney Particle Study (SPS) campaign in 2012. Benzene, toluene, C 8 aromatics, isoprene, formaldehyde and acetaldehyde were selected for the comparison, based on objective selection criteria from the available data. Bottom-up uncertainty analyses were undertaken for each compound and each measurement system. Top-down uncertainties were quantified via the intercomparisons. In all seven comparisons, the correlations between independent measurement techniques were high with R 2 values with a median of 0.92 (range 0.75-0.98) and small root mean square of the deviations (RMSD) of the observations from the regression line with a median of 0.11 (range 0.04-0.23 ppbv). These results give a high degree of confidence that for each comparison the response of the two independent techniques is dominated by the same constituents. The slope and intercept as determined by reduced major axis (RMA) regression gives a different story. The slopes varied considerably with a median of 1.25 and a range of 1.16-2.01. The intercepts varied with a median of 0.04 and a range of −0.03 to 0.31 ppbv. An ideal comparison would give a slope of 1.00 and an intercept of 0.Some sources of uncertainty that are poorly quantified by the bottom-up uncertainty analysis method were identified, including: contributions of non-target compounds to the measurement of the target compound for benzene, toluene and isoprene by PTR-MS as well as the under-reporting of formaldehyde, acetaldehyde and acetone by the DNPH technique. As well as these, this study has identified a specific interference of liquid water with acetone measurements by the DNPH technique.These relationships reported for Sydney 2012 were incorporated into a larger analysis with 61 similar published inter-comparison studies for the same compounds. Overall, for the light aromatics, isoprene and the C 1 -C 3 carbonyls, the uncertainty in a set of measurements varies by a factor of between 1.5 and 2. These uncertainties (∼ 50 %) are significantly higher than uncertainties estimated using standard propagation of error methods, which in this case were ∼ 22 % or less, and are the result of the presence of poorly understood or neglected processes that affect the measurement and its uncertainty. The uncertainties in VOC measurements identified here should be considered when assessing the reliability of VOC measurements from routine monitoring with individual, stand-alone instruments; when utilizing VOC da...

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Section: Proton-transfer-reaction Mass Spectrometry (Ptr-ms)mentioning

confidence: 99%

“…Rogers et al, 2006;Inomata et al, 2008;Dunne et al, 2012). Where possible, for the compounds examined in this study, a method was developed to correct the PTR-MS target ion signal for the presence of known and quantifiable interference.…”

Section: Proton-transfer-reaction Mass Spectrometry (Ptr-ms)mentioning

confidence: 99%

Comparison of VOC measurements made by PTR-MS, adsorbent tubes–GC-FID-MS and DNPH derivatization–HPLC during the Sydney Particle Study, 2012: a contribution to the assessment of uncertainty in routine atmospheric VOC measurements

et al. 2018

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“…The SRI enables identification of VOC isomers indistinguishable with H 3 O + ionization, e.g. aldehyde and ketone isomers (Dunne et al, 2012). In this work, NO + was used to differentiate aldehyde and ketone isomers, because NO + reacts with aldehydes to produce mainly dehydrogenated cations (M-H) + , whereas its reaction with ketones yields NO + cluster ions (M + NO) + (Jordan et al, 2009).…”

Section: Flow Tube Apparatus and Detection Schemesmentioning

confidence: 99%

Formation of gas-phase carbonyls from heterogeneous oxidation of polyunsaturated fatty acids at the air–water interface and of the sea surface microlayer

et al. 2014

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Motivated by the potential for reactive heterogeneous chemistry occurring at the ocean surface, gas-phase products were observed when a reactive sea surface microlayer (SML) component, i.e. the polyunsaturated fatty acids (PUFA) linoleic acid (LA), was exposed to gas-phase ozone at the air-seawater interface. Similar oxidation experiments were conducted with SML samples collected from two different oceanic locations, in the eastern equatorial Pacific Ocean and from the west coast of Canada. Online proton-transferreaction mass spectrometry (PTR-MS) University of Colorado light-emitting diode cavity-enhanced differential optical absorption spectroscopy (LED-CE-DOAS) were used to detect oxygenated gas-phase products from the ozonolysis reactions. The LA studies indicate that oxidation of a PUFA monolayer on seawater gives rise to prompt and efficient formation of gas-phase aldehydes. The products are formed via the decomposition of primary ozonides which form upon the initial reaction of ozone with the carbon-carbon double bonds in the PUFA molecules. In addition, two highly reactive dicarbonyls, malondialdehyde (MDA) and glyoxal, were also generated, likely as secondary products. Specific yields relative to reactant loss were 78 %, 29 %, 4 % and < 1 % for n-hexanal, 3-nonenal, MDA and glyoxal, respectively, where the yields for MDA and glyoxal are likely lower limits. Heterogeneous oxidation of SML samples confirm for the first time that similar carbonyl products are formed via ozonolysis of environmental samples. Recent field observations indicate missing sources for oxygenated hydrocarbons from the oceans in atmospheric models (Myriokefalitakis et al., 2008; Sinreich et al., 2010). It is known that the SML is a complex organic and inorganic mixture (Pogorzelski and Kogut, 2003;Kozarac et al., 2005). The organic substances in the SML, including proteins, polysaccharides, humic-type materials and lipids, are likely produced from marine biota (Wilson and Collier, 1972;Gašparovic et al., 1998). As a main component of lipids, fatty acids (FA), including polyunsaturated FA (PUFA) have been detected in considerable amounts in sea surface water with concentrations of 3-200 µg L −1 (Marty et al., 1979;Derieux et al., 1998;André et al., 2004;Parrish et al., 2005;Blaženka et al., 2007). PUFA contribute as much as ∼43 % of the total FA measured, for example, in sub-Arctic Norwegian fjords Published by Copernicus Publications on behalf of the European Geosciences Union.

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“…Only m/z values that were detected above the method detection limit (MDL) greater than 25 % of the time, and had peak-to-noise ratios greater than 5 (95th percentile/MDL), were reported. Further details are available in Galbally et al (2007) and Dunne et al (2012Dunne et al ( , 2018. The estimated uncertainty listed in Table 1 was taken from Dunne et al (2018).…”

Section: Proton-transfer-reaction Mass Spectrometermentioning

confidence: 99%

Comprehensive aerosol and gas data set from the Sydney Particle Study

Keywood

Selleck

Reisen

et al. 2019

Earth Syst. Sci. Data

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The Sydney Particle Study involved the comprehensive measurement of meteorology, particles and gases at a location in western Sydney during February-March 2011 and April-May 2012. The aim of this study was to increase scientific understanding of particle formation and transformations in the Sydney airshed. In this paper we describe the methods used to collect and analyse particle and gaseous samples, as well as the methods employed for the continuous measurement of particle concentrations, particle microphysical properties, and gaseous concentrations. This paper also provides a description of the data collected and is a metadata record for the data sets published in Keywood et al. (2016a, https://doi.org/10.4225/08/57903B83D6A5D) and Keywood et al. (2016b, https://doi.org/10.4225/08/5791B5528BD63).Published by Copernicus Publications.

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Interference in the PTR-MS measurement of acetonitrile at m/z 42 in polluted urban air—A study using switchable reagent ion PTR-MS

Cited by 29 publications

References 17 publications

Comparison of VOC measurements made by PTR-MS, adsorbent tubes–GC-FID-MS and DNPH derivatization–HPLC during the Sydney Particle Study, 2012: a contribution to the assessment of uncertainty in routine atmospheric VOC measurements

Comparison of VOC measurements made by PTR-MS, adsorbent tubes–GC-FID-MS and DNPH derivatization–HPLC during the Sydney Particle Study, 2012: a contribution to the assessment of uncertainty in routine atmospheric VOC measurements

Formation of gas-phase carbonyls from heterogeneous oxidation of polyunsaturated fatty acids at the air–water interface and of the sea surface microlayer

Comprehensive aerosol and gas data set from the Sydney Particle Study

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