Measurement of alkyl and multifunctional organic nitrates by proton-transfer-reaction mass spectrometry

Duncianu, Marius; David, Marc; Kartigueyane, Sakthivel; Cirtog, Manuela; Doussin, Jean‐François; Picquet‐Varrault, Bénédicte

doi:10.5194/amt-10-1445-2017

Cited by 24 publications

(31 citation statements)

References 87 publications

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“…Addition of NO 2 to the system in experiment 11 resulted in significantly reduced yields, with overall distribution remaining similar and no new peaks or evidence of nitrate-containing compounds observed. Nonetheless, alkyl nitrates are known to readily lose HNO 3 after protonation in the PTR-TOF, resulting in the formation of bare alkyl ions (D'Anna et al, 2005;Aoki et al, 2007;Duncianu et al, 2017). Proposed structures for some of these larger second-generation products, along with plausible formation mechanisms, are shown in Fig.…”

Section: Characterisation Of Gas and Particle Phasesmentioning

confidence: 99%

Ozonolysis of <i>α</i>-phellandrene – Part 1: Gas- and particle-phase characterisation

et al. 2017

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Abstract. The ozonolysis of α-phellandrene, a highly reactive conjugated monoterpene largely emitted by Eucalypt species, is characterised in detail for the first time using a smog chamber at the Guangzhou Institute of Geochemistry, Chinese Academy of Sciences. Gas-phase species were monitored by a proton-transfer-reaction time-of-flight mass spectrometer (PTR-TOF), with yields from a large number of products obtained, including formaldehyde (5-9 %), acetaldehyde (0.2-8 %), glyoxal (6-23 %), methyl glyoxal (2-9 %), formic acid (22-37 %) and acetic acid (9-22 %). Higher m/z second-generation oxidation products were also observed, with products tentatively identified according to a constructed degradation mechanism. OH yields from α-phellandrene and its first-generation products were found to be 35 ± 12 and 15 ± 7 %, respectively, indicative of prominent hydroperoxide channels. An average first-generation rate coefficient was determined as 1.0 ± 0.7 × 10 −16 cm 3 molecule −1 s −1 at 298 K, showing ozonolysis as a dominant loss process for both α-phellandrene and its first-generation products in the atmosphere. Endocyclic conjugation in α-phellandrene was also found to be conducive to the formation of highly condensible products with a large fraction of the carbon mass partitioning into the aerosol phase, which was monitored with a scanning mobility particle sizer (SMPS) and a high-resolution timeof-flight aerosol mass spectrometer (AMS). Nucleation was observed almost instantaneously upon ozonolysis, indicating the rapid formation of extremely low-volatility compounds. Particle nucleation was found to be suppressed by the addition of either NO 2 or a Criegee scavenger, with it being proposed that stabilised Criegee intermediates are important for new particle formation in the system. Aerosol yields ranged from 25 to 174 % depending on mass loadings, with both first-and second-generation products identified as large contributors to the aerosol mass. In short, with a high chemical reactivity and aerosol-forming propensity, α-phellandrene is expected to have an immediate impact on the local environment to which it is emitted, with ozonolysis likely to be an important contributor to the significant blue haze and frequent nocturnal nucleation events observed over Eucalypt forests.

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Section: Characterisation Of Gas and Particle Phasesmentioning

confidence: 99%

Ozonolysis of <i>α</i>-phellandrene – Part 1: Gas- and particle-phase characterisation

et al. 2017

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“…For the values reported with no uncertainty, we arbitrarily assigned a 100 % uncertainty to prevent an excessive contribution of unclear determinations. This was the case, for example, for all the determinations reported in the works from Anbar et al (1966) and Eibenberger (1980).…”

Section: Database For the Extended Sarmentioning

confidence: 80%

On the importance of atmospheric loss of organic nitrates by aqueous-phase ●OH oxidation

González-Sánchez

Brun

et al. 2021

Atmos. Chem. Phys.

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Abstract. Organic nitrates are secondary species in the atmosphere. Their fate is related to the chemical transport of pollutants from polluted areas to more distant zones. While their gas-phase chemistry has been studied, their reactivity in condensed phases is far from being understood. However, these compounds represent an important fraction of organic matter in condensed phases. In particular, their partition to the aqueous phase may be especially important for oxidized organic nitrates for which water solubility increases with functionalization. This work has studied for the first time the aqueous-phase ⚫OH-oxidation kinetics of four alkyl nitrates (isopropyl nitrate, isobutyl nitrate, 1-pentyl nitrate, and isopentyl nitrate) and three functionalized organic nitrates (α-nitrooxyacetone, 1-nitrooxy-2-propanol, and isosorbide 5-mononitrate) by developing a novel and accurate competition kinetic method. Low reactivity was observed, with kOH ranging from 8×107 to 3.1×109 L mol−1 s−1 at 296±2 K. Using these results, a previously developed aqueous-phase structure–activity relationship (SAR) was extended, and the resulting parameters confirmed the extreme deactivating effect of the nitrate group, up to two adjacent carbon atoms. The achieved extended SAR was then used to determine the ⚫OH-oxidation rate constants of 49 organic nitrates, including hydroxy nitrates, ketonitrates, aldehyde nitrates, nitrooxy carboxylic acids, and more functionalized organic nitrates such as isoprene and terpene nitrates. Their multiphase atmospheric lifetimes towards ⚫OH oxidation were calculated using these rate constants, and they were compared to their gas-phase lifetimes. Large differences were observed, especially for polyfunctional organic nitrates: for 50 % of the proposed organic nitrates for which the ⚫OH reaction occurs mainly in the aqueous phase (more than 50 % of the overall removal), their ⚫OH-oxidation lifetimes increased by 20 % to 155 % under cloud/fog conditions (liquid water content LWC = 0.35 g m−3). In particular, for 83 % of the proposed terpene nitrates, the reactivity towards ⚫OH occurred mostly (>98 %) in the aqueous phase, while for 60 % of these terpene nitrates, their lifetimes increased by 25 % to 140 % compared to their gas-phase reactivity. We demonstrate that these effects are of importance under cloud/fog conditions but also under wet aerosol conditions, especially for the terpene nitrates. These results suggest that considering aqueous-phase ⚫OH-oxidation reactivity of biogenic nitrates is necessary to improve the predictions of their atmospheric fate.

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“…Isopentyl nitrate and 2-ethylhexyl nitrate were analyzed by PTR-MS for the first time. The other compounds, isopropyl nitrate, isobutyl nitrate and 1-pentyl nitrate were previously investigated by Duncianu et al, 2017 andAoki et al, 2007. Table S3 compiles the different fragments and relative intensities for all the studied organic nitrates in this work.…”

Section: Ptr-msmentioning

confidence: 99%

On the importance of atmospheric loss of organic nitrates by aqueous-phase ·OH-oxidation

González-Sánchez¹,

Brun²,

Wu³

et al. 2020

Preprint

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Abstract. Organic nitrates are secondary species in the atmosphere. Their fate is related to the chemical transport of pollutants from polluted areas to more distant zones. While their gas-phase chemistry has been studied, their reactivity in condensed phases is far from being understood. However, these compounds represent an important fraction of organic matter in condensed phases. In particular, their partition to the aqueous-phase may be especially important for oxidized organic nitrates for which water solubility increase with functionalization. This work has studied for the first time the aqueous-phase ·OH-oxidation kinetics of 5 alkyl nitrates (isopropyl nitrate, isobutyl nitrate, 1-pentyl nitrate, isopentyl nitrate and 2-ethylhexyl nitrate) and 3 functionalized organic nitrates (α-nitrooxyacetone, 1-nitrooxy-2-propanol and isosorbide 5-mononitrate) by developing a novel and accurate competition kinetic method. Low reactivity was confirmed, with kOH (at 296 ± 2 K) ranging from 8·107 to 2.5·109 L mol−1 s−1. Using these results, the previously developed aqueous-phase Structure Activity Relationship (SAR) was extended, and the resulting parameters confirmed the extreme deactivating effect of the nitrate group, up to two adjacent carbon atoms. The achieved extended SAR was then used to determine the ·OH-oxidation rate constants of 49 organic nitrates, including hydroxy nitrates, ketonitrates, aldehyde nitrates, nitrooxy carboxylic acids and more functionalized organic nitrates such as isoprene and terpene nitrates. Their multiphase atmospheric lifetimes towards ·OH-oxidation were calculated using these rate constants, and compared to their gas-phase lifetimes. Large differences were observed, especially for polyfunctional organic nitrates: for 50 % of the proposed organic nitrates for which ·OH-reaction occurs mainly in the aqueous-phase (more than 50 % of the overall removal) their ·OH-oxidation lifetimes increased by 20 % to 155 % under cloud/fog conditions (LWC = 0.35 g m−3). In particular, for 83 % of the proposed terpene nitrates, the reactivity towards ·OH occurred mostly (> 98 %) in the aqueous-phase while for 60 % of these terpene nitrates their lifetimes increased by 25 % to 140 % compared to their gas-phase reactivity. We demonstrate that these effects are of importance under cloud/fog conditions, but also under wet aerosol conditions, especially for the terpene nitrates. These results suggest that taking into account aqueous-phase ·OH-oxidation reactivity of biogenic nitrates is necessary to improve the predictions of their atmospheric fate.

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Measurement of alkyl and multifunctional organic nitrates by proton-transfer-reaction mass spectrometry

Cited by 24 publications

References 87 publications

Ozonolysis of <i>α</i>-phellandrene – Part 1: Gas- and particle-phase characterisation

Ozonolysis of <i>α</i>-phellandrene – Part 1: Gas- and particle-phase characterisation

On the importance of atmospheric loss of organic nitrates by aqueous-phase ●OH oxidation

On the importance of atmospheric loss of organic nitrates by aqueous-phase ·OH-oxidation

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Measurement of alkyl and multifunctional organic nitrates by proton-transfer-reaction mass spectrometry

Cited by 24 publications

References 87 publications

Ozonolysis of &lt;i&gt;α&lt;/i&gt;-phellandrene – Part 1: Gas- and particle-phase characterisation

Ozonolysis of &lt;i&gt;α&lt;/i&gt;-phellandrene – Part 1: Gas- and particle-phase characterisation

On the importance of atmospheric loss of organic nitrates by aqueous-phase ●OH oxidation

On the importance of atmospheric loss of organic nitrates by aqueous-phase ·OH-oxidation

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Ozonolysis of <i>α</i>-phellandrene – Part 1: Gas- and particle-phase characterisation

Ozonolysis of <i>α</i>-phellandrene – Part 1: Gas- and particle-phase characterisation