title: Carbon-specific analysis of humic-like substances in atmospheric aerosol and precipitation samples.
abstract: A new approach for the carbon-specific determination of humic-like substances (HULIS) in atmospheric aerosols is presented. The method is based on a two-step isolation procedure of HULIS and the determination of HULIS carbon with a dissolved organic carbon analyzer. In the first step, a C18 solid-phase extraction is performed to separate HULIS from inorganic and hydrophilic organic sample constituents in aqueous sample solutions. The second isolation step is conducted on a strong anion exchanger to separate HULIS from remaining carbonaceous compounds. This ion chromatographic separation step including the subsequent on-line detection of HULIS carbon was performed fully automated to avoid the risk of sample contamination and to enhance the reproducibility of the method. With a 5-mL sample volume, a limit of detection of 1.0 mg C/L was obtained; this corresponds to an absolute amount of 5 microg of HULIS carbon. The reproducibility of the method given as the relative standard deviation was 4.3% (n = 10). The method was applied for the determination of water-soluble HULIS in airborne particulate matter. PM10 concentrations at an urban site in Vienna, Austria, ranged from around 0.1 to 1.8 microg of C/m(3) (n = 49); the fraction of water-soluble HULIS in OC was 12.1 +/- 7.2% (n = 49).
authors.affiliation: Institute of Chemical Technologies and Analytics, Vienna University of Technology, Austria. ALimbeck@mail.zserv.tuwien.ac.at
authors.forename: Andreas
authors.initials: A
authors.lastname: Limbeck
authors.forename: Markus
authors.initials: M
authors.lastname: Handler
authors.forename: Bernhard
authors.initials: B
authors.lastname: Neuberger
authors.forename: Barbara
authors.initials: B
authors.lastname: Klatzer
authors.forename: Hans
authors.initials: H
authors.lastname: Puxbaum