Authors:	Zhang, Yun Wang, Kai Tong, Haijie Huang, Ru-Jin Hoffmann, Thorsten
Title:	The maximum carbonyl ratio (MCR) as a new index for the structural classification of secondary organic aerosol components
Online publication date:	14-Nov-2022
Year of first publication:	2021
Language:	english
Abstract:	Rationale Organic aerosols (OA) account for a large fraction of atmospheric fine particulate matter and thus are affecting climate and public health. Elucidation of the chemical composition of OA is the key for addressing the role of ambient fine particles at the atmosphere–biosphere interface and mass spectrometry is the main method to achieve this goal. Methods High-resolution mass spectrometry (HRMS) is on its way to becoming one of the most prominent analytical techniques, also for the analysis of atmospheric aerosols. The combination of high mass resolution and accurate mass determination allows the elemental compositions of numerous compounds to be easily elucidated. Here a new parameter for the improved classification of OA is introduced – the maximum carbonyl ratio (MCR) – which is directly derived from the molecular composition and is particularly suitable for the identification and characterization of secondary organic aerosols (SOA). Results The concept is exemplified by the analysis of ambient OA samples from two measurement sites (Hyytiälä, Finland; Beijing, China) and of laboratory-generated SOA based on ultrahigh-performance liquid chromatography (UHPLC) coupled to Orbitrap MS. To interpret the results, MCR–Van Krevelen (VK) diagrams are generated for the different OA samples and the individual compounds are categorized into specific areas in the diagrams. The results show that the MCR index is a valuable parameter for representing atmospheric SOA components in composition and structure-dependent visualization tools such as VK diagrams. Conclusions The MCR index is suggested as a tool for a better characterization of the sources and the processing of atmospheric OA components based on HRMS data. Since the MCR contains information on the concentration of highly electrophilic organic compounds in particulate matter (PM) as well as on the concentration of organic (hydro)peroxides, the MCR could be a promising metric for identifying health-related particulate matter parameters by HRMS.
DDC:	540 Chemie 540 Chemistry and allied sciences
Institution:	Johannes Gutenberg-Universität Mainz
Department:	FB 09 Chemie, Pharmazie u. Geowissensch.
Place:	Mainz
ROR:	https://ror.org/023b0x485
DOI:	http://doi.org/10.25358/openscience-8083
Version:	Published version
Publication type:	Zeitschriftenaufsatz
License:	CC BY-NC
Information on rights of use:	https://creativecommons.org/licenses/by-nc/4.0/
Journal:	Rapid communications in mass spectrometry 35 14
Pages or article number:	e9113
Publisher:	Wiley Interscience
Publisher place:	New York, NY
Issue date:	2021
ISSN:	1097-0231
Publisher DOI:	10.1002/rcm.9113
Appears in collections:	JGU-Publikationen