Atmospheric aerosols significantly impact both climate and human health by affecting cloud formation, altering the Earth's radiative balance, and contributing to respiratory and cardiovascular diseases. Gaining detailed molecular insight into their composition is essential to understand their origin, transformation, and potential toxicity.

High-resolution mass spectrometry (HRMS), such as Orbitrap, FT-ICR-MS or HR-TOF-MS, allows for the precise determination of mass-to-charge ratios and the assignment of elemental compositions with sub-ppm accuracy. This high level of mass resolution and accuracy is critical for characterizing the thousands of chemically diverse organic compounds found in complex aerosol mixtures.

Ion mobility spectrometry (IMS) adds a further analytical dimension by separating ions in the gas phase based on their size and shape. This enables the determination of collision cross sections, intrinsic structural properties of molecules, offering valuable information for distinguishing isomeric and structurally similar species, which are frequently encountered in organic aerosols. IMS also enhances confidence in compound annotation and supports structural elucidation when combined with HRMS data.

Liquid chromatography (LC), often used as the first stage in the analytical workflow, provides efficient separation of compounds based on polarity and molecular interactions prior to ionization. This reduces ionization suppression effects and improves both the sensitivity and clarity of downstream IMS and HRMS analyses. In combination, LC-IMS-HRMS provides a powerful multidimensional approach for the in-depth characterization of the organic aerosol fraction.

University of Rostock
Institute of Chemistry
Division of Analytical and Technical Chemistry
Helly Johanna Hansen
Albert-Einstein-Straße 25
18059 Rostock (Germany)

Tel.: +49 (0) 381 498 - 8993
helly.hansenuni-rostockde