AAAR 34th Annual Conference
October 12 - October 16, 2015
Hyatt Regency
Minneapolis, Minnesota, USA
Abstract View
Chemical Analysis of Ambient Air In Real Time by Secondary Electrospray Ionization High-Resolution Mass Spectrometry
XUE LI, Pablo M.-L. Sinues, Renato Zenobi, Jinan University; ETH Zurich
Abstract Number: 126 Working Group: Instrumentation and Methods
Abstract Secondary organic aerosol (SOA) is a worldwide concern due to its significant influence on the global climate change, air quality and human health. The atmospheric chemistry of volatile organic compounds (VOCs) is intimately involved in the formation of SOA in ambient air under both clean and polluted atmospheric conditions. In this study, ambient air was directly monitored with a time resolution of 1.5 minute using an ambient mass spectrometry-based technique, secondary electrospray ionization high-resolution mass spectrometry (SESI-HRMS). Hundreds of positive and negative ions were detected in the range of m/z 40–350, and identified as C$_xH$_y, C$_xH$_yO$_z, C$_xH$_yN$_mO$_z and C$_xH$_yO$_zS$_n (e.g., C$_5H$_8, C$_3H$_7O, C$_3H$_4O$_4, C$_6H$_(11)NO$_3, C$_(13)H$_(24)O$_4S$_2) based on the HRMS and isotope distribution data. This results imply the presence of alkenes, alcohols, ketones, aldehydes, aliphatic acids as well as other organic compounds in ambient air. Significant changes of intensity of individual signal within minutes during a field measurement period (9:00–14:30 on December 27, 2013, at the Hönggerberg campus of ETH Zürich) have been successfully captured, even for isobaric compounds that can be distinguished thanks to the high mass resolution, e.g., C$_3H$_6N$_3O$_2 (m/z 116.0460) and C$_4H$_(10)N$_3O (m/z 116.0824). In conclusion, SESI-HRMS is a promising tool for studying the atmospheric chemistry of VOCs by providing accurate identification of signals obtained from non-targeted analysis and time-resolved characterization of atmospheric VOCs.