Articles | Volume 10, issue 4
https://doi.org/10.5194/amt-10-1445-2017
https://doi.org/10.5194/amt-10-1445-2017
Research article
 | 
18 Apr 2017
Research article |  | 18 Apr 2017

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

Marius Duncianu, Marc David, Sakthivel Kartigueyane, Manuela Cirtog, Jean-François Doussin, and Benedicte Picquet-Varrault

Abstract. A commercial PTR-TOF-MS has been optimized in order to allow the measurement of individual organic nitrates in the atmosphere. This has been accomplished by shifting the distribution between different ionizing analytes, H3O+∕ H3O+(H2O)n or NO+∕ NO2+. The proposed approach has been proven to be appropriate for the online detection of individual alkyl nitrates and functionalized nitrates. It has been shown that hydroxyl and ketonitrates have a high affinity towards NO+, leading to the formation of an adduct that allows the easy identification of the organic nitrate (R) from the R–NO+ ion signal. The recorded sensitivities for both ionization modes correspond to detection limits of tens of ppt min−1 in the case of hydroxy- and ketonitrates. Alkyl nitrates exhibit a moderate affinity towards NO+ ionization leading to detection units of few hundreds of ppt and the highest sensitivity in H3O+ mode was obtained for the water adducts signals. However, this method exhibits much lower capabilities for the detection of peroxyacetyl nitrates with detection limits in the ppb range.

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Short summary
A commercial PTR-ToF-MS has been optimized in order to allow the measurement of individual organic nitrates in the atmosphere. This has been accomplished by shifting the distribution between different ionizing analytes. The proposed approach has been proved to be appropriate for the online detection of individual alkyl nitrates and functionalized nitrates.