Characterization of high molecular weight compounds in urban atmospheric particles

V. Samburova (1) , M. Kalberer (1) , R. Zenobi (1)

1 Department of Analytical Chemistry, Laboratory of Organic Chemistry

The chemical nature of a large fraction of ambient organic aerosol particles is not known. However, high molecular weight compounds (often named humic-like substances) have recently been detected by several authors and these compounds seem to account for a significant fraction of the total organic aerosol mass. Due to the unknown chemical structure of these compounds a quantification as well as a determination of their molecular weight is difficult. In this paper we investigate water soluble humic-like substances in ambient urban aerosol using size exclusion chromatography-UV spectroscopy and laser desorption/ionization mass spectrometry. A careful method evaluation shows that both methods complement each other and that both are needed to learn more about the molecular weight distribution and the concentration of humic-like substances. An upper molecular weight limit of humic-like substances of about 700 Da and a concentration of 0.2?1.8 µg/m³ air can be estimated corresponding to 8?33% of the total organic carbon for an urban background site.

Domaines: Océan, Atmosphère

V. Samburova, M. Kalberer, R. Zenobi. Characterization of high molecular weight compounds in urban atmospheric particles. Atmospheric Chemistry and Physics Discussions, 2005, 5 (1), pp.437-454. ⟨hal-00300944⟩