Characterization of high molecular weight compounds in urban atmospheric particles V. Samburova, R. Zenobi, and M. Kalberer Department of Chemistry and Applied Biosciences, Swiss Federal Institute of Technology Zurich (ETH), 8093 Zürich, Switzerland
Abstract. The chemical nature of a large mass fraction of ambient organic aerosol
particles is not known. 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 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 (LDI-MS).
LDI-MS was used for the first time to investigate HULIS from atmospheric
aerosols. A careful evaluation of the two method 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 0.3-1.6 µg/m3 air can be
estimated, corresponding to 9-30% of the total organic carbon for an
urban background site.
Citation: Samburova, V., Zenobi, R., and Kalberer, M.: Characterization of high molecular weight compounds in urban atmospheric particles, Atmos. Chem. Phys., 5, 2163-2170, doi:10.5194/acp-5-2163-2005, 2005.