Real-Time Analysis of Ambient Organic Aerosols Using Aerosol Flowing Atmospheric-Pressure Afterglow Mass Spectrometry (AeroFAPA-MS)

Abstract

Organic compounds contribute to a major fraction of atmospheric aerosols and have significant impacts on climate and human health. However, because of their chemical complexity, their measurement remains a major challenge for analytical instrumentation. Here we present the development and characterization of a new soft ionization technique that allows mass spectrometric real-time detection of organic compounds in aerosols. The aerosol flowing atmospheric-pressure afterglow (AeroFAPA) ion source is based on a helium glow discharge plasma, which generates excited helium species and primary reagent ions. Ionization of the analytes occurs in the afterglow region after thermal desorption and produces mainly intact quasimolecular ions, facilitating the interpretation of the acquired mass spectra. We illustrate that changes in aerosol composition and concentration are detected on the time scale of seconds and in the ng m(-3) range. Additionally, the successful application of AeroFAPA-MS during a field study in a mixed forest region is presented. In general, the observed compounds are in agreement with previous offline studies; however, the acquisition of chemical information and compound identification is much faster. The results demonstrate that AeroFAPA-MS is a suitable tool for organic aerosol analysis and reveal the potential of this technique to enable new insights into aerosol formation, growth, and transformation in the atmosphere.

Chemical characterization of α‐pinene secondary organic aerosol constituents using gas chromatography, liquid chromatography, and paper spray‐based mass spectrometry techniques

“…All organosulfates identified had a characteristic HSO 4 − ( m / z 97) fragment. The organosulfates identified have been observed in previous experiments involving the OH radical initiated oxidation of α‐pinene, as well as in ambient measurements . The assignment of structures is based on the rationalization of likely fragmentation mechanisms.…”

“…The organosulfates identified have been observed in previous experiments involving the OH radical initiated oxidation of α-pinene, [7,12,51] as well as in ambient measurements. [52][53][54][55][56] The assignment of structures is based on the rationalization of likely fragmentation mechanisms. The tandem mass spectrum of each organosulfate is shown in Fig.…”

Online molecular characterisation of organic aerosols in an atmospheric chamber using extractive electrospray ionisation mass spectrometry

“…A number of recent studies have therefore developed online or semi-continuous atmospheric-pressure ionisation (API) MS techniques (Bateman et al, 2009;Brüggemann et al, 2015;Clark et al, 2014;Nah et al, 2013;Pereira et al, 2014;Vogel et al, 2013;Zhang et al, 2015;Zhao et al, 2017b). In this paper, we focus on the application of one such approach to organic aerosol analysis, namely extractive electrospray ionisation (EESI) MS.…”

Critical assessment of ionization patterns and applications of ambient desorption/ionization mass spectrometry using FAPA–MS

“…[11,13] So far, the FAPA source has been used for applications such as the detection of explosives and pesticides, [9,13] the analysis of human urine [14] or the identification of compounds in airborne particulate matter. [15] Commonly, the source is described as a soft ionization technique that favors the formation of quasimolecular ions, yielding [M + H] + and [M À H] À in the positive and the negative mode, respectively. However, adduct formation and/or fragmentation processes occurring in the afterglow region are rarely discussed.…”