Measurement of alkyl and multifunctional organic nitrates by Proton Transfer Reaction Mass Spectrometry
Marius Duncianu, Marc David, Sakthivel Kartigueyane, Manuela Cirtog, Jean-Francois Doussin, and Benedicte Picquet-Varrault
Laboratoire Interuniversitaire des Systèmes Atmosphériques (LISA), UMR-CNRS 7583, Université Paris-Est-Créteil (UPEC) et Université Paris Diderot (UPD), France
Received: 05 Oct 2016 – Accepted for review: 22 Oct 2016 – Discussion started: 07 Nov 2016
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 proved to be appropriate for the on-line detection of individual alkyl nitrates and functionalized nitrates. It has been shown that hydroxyl- and keto-nitrates have a high affinity towards NO+, leading to the formation of an adduct that allows to easily identify the organic nitrate (R) with 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 keto-nitrates. 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. This method exhibits however lower capabilities for the detection of PANs with detection limits in the ppb range.
Duncianu, M., David, M., Kartigueyane, S., Cirtog, M., Doussin, J.-F., and Picquet-Varrault, B.: Measurement of alkyl and multifunctional organic nitrates by Proton Transfer Reaction Mass Spectrometry, Atmos. Meas. Tech. Discuss., doi:10.5194/amt-2016-318, in review, 2016.