Decreasing the Uncertainty in the Comparison of Molecular Fingerprints of Organic Aerosols with H/D Exchange Mass Spectrometry

Alexander Zherebker, Oliver Babcock, Diana L. Pereira, Sara D’Aronco, Daniele Filippi, Lidia Soldà, Vincent Michoud, Aline Gratien, Manuela Cirtog, Christopher Cantrell, Paola Formenti, Chiara Giorio

Research output: Contribution to journalArticlepeer-review

Abstract

High-resolution mass spectrometry (HRMS) has become an indispensable tool in the characterization of organic aerosols (OA) providing information on air quality, health assessment, climate trends, reactions, and source apportionment. Spectra-derived lists of formulas and their relative abundances are used to compare ambient OA from different sources or to monitor secondary OA formation under controlled laboratory conditions in smog chamber experiments. Various techniques are implemented to visualize common and unique features, series of precursors, and products. The disadvantage of this conventional approach is in associating elemental compositions to specific compounds, while due to several analytical limitations, the structural information remains hidden. We argue that some of the conclusions derived from this data analysis can be misleading. In this study, we applied in-ESI source H/D exchange (HDX), which facilitated enumeration of labile protons in molecules behind elemental compositions of OA. We applied this technique to compare OA from three different locations representing urban, forest, and marine environments and to examine tentative chemical information derived from Kendrick mass defect (KMD) series analysis. Significant discrepancies were found between numbers of labile protons in protogenic functional groups and the stoichiometry of chemical reactions, which are associated with KMD series. Only a portion of chemical pairs matched target stoichiometries, which highlights the existing limitations in environmental applications of conventional formula-based HRMS data interpretation strategies.

Original languageEnglish
Pages (from-to)20468-20479
Number of pages12
JournalEnvironmental Science and Technology
Volume58
Issue number46
DOIs
StatePublished - 19 Nov 2024
Externally publishedYes

Keywords

  • KMD series
  • chemical pairs
  • high-resolution mass spectrometry
  • isomers
  • labile protons
  • nontarget analysis
  • structural descriptor

ASJC Scopus subject areas

  • General Chemistry
  • Environmental Chemistry

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