Dresden 2026 – scientific programme
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 46: Poster II
CPP 46.3: Poster
Thursday, March 12, 2026, 09:30–11:30, P5
Photooxidation of vanillic acid at the air-water interface — •Manuel Hofmann1,2 and Ellen H.G. Backus1,2 — 1Institute of Physical Chemistry, Faculty of Chemistry, University of Vienna, Währinger Str. 42, 1090 Vienna, Austria — 2University of Vienna, Vienna Doctoral School in Chemistry (DoSChem), Währinger Str. 42, 1090 Vienna, Austria
Phenolic compounds like vanillic acid, emitted from biomass burning, can form secondary organic aerosols (SOA) through aqueous phase reactions. Photooxidation of vanillic acid is a potential source of Humic-Like Substances (HULIS), that influence atmospheric chemistry through light absorption.[1]
The air-water interface provides a distinct chemical environment where structural behavior and reactions may differ from those in bulk. To specifically probe this interface, sum-frequency generation (SFG) spectroscopy and surface tension measurements are employed, offering complementary insights into molecular behavior.[2]
This study examines vanillic acid at the air-water interface across different pH values, before and after UV/H2O2-induced photooxidation. Control experiments with vanillic acid alone separate direct photolysis from radical mediated processes. Preliminary SFG spectra reveal pH-dependent vibrational signatures of adsorbed species and significant changes upon photoreaction. The goal is to identify reaction products, structural changes, and how pH affects vanillic acid photoreactivity.
[1]S. Tang et al., ACS Earth Space Chem., 4 (2020) 862-872.[2]C.-M. Saak et al., J. Phys. Chem. Lett., 15 (2024) 4546-4559.
Keywords: Sum frequency generation (SFG) spectroscopy; Air-water interface; Surface structure; Photochemistry