title: Solid phase dosing and sampling technique to determine partition coefficients of hydrophobic chemicals in complex matrixes.
abstract: Determination of polymer-water and dissolved organic carbon (DOC)-water distribution coefficients of very hydrophobic chemicals (log K0w > 6) is not straightforward. Poor water solubility of the test compounds complicates the spiking and analysis of actual freely dissolved concentrations. By dosing a system via a PDMS-fiber and monitoring the depletion in the polymer, spiking and analysis of concentrations in the aqueous phase are avoided, and sorption to the polymer and other hydrophobic phases can be determined easily and accurate. In this publication we report the determination of poly(dimethyl-siloxane) (PDMS)-water, and Aldrich humic acid-water distribution coefficients for six PAHs with log K0w values varying from 4.56 to 6.85. The distribution coefficients to a PDMS fiber llog Kf) and the DOC (log KDOC) range from 3.86 to 5.39 and 4.78 to 7.43, respectively. Even for the most hydrophobic compounds, the distribution coefficients show small standard errors (< or = 0.05 log units). Therefore, this method might be applied to determine sorption coefficients of numerous, even more hydrophobic compounds, to humic acids as well as other dissolved hydrophobic matrixes.
authors.affiliation: Institute for Risk Assessment Sciences (IRAS), Utrecht University, Yalelaan 2, P.O. Box 80176, 3508 TD Utrecht, The Netherlands. t.terlaak@iras.uu.nl
authors.forename: Thomas L
authors.initials: TL
authors.lastname: ter Laak
authors.forename: Mojca
authors.initials: M
authors.lastname: Durjava
authors.forename: Jaap
authors.initials: J
authors.lastname: Struijs
authors.forename: Joop L M
authors.initials: JL
authors.lastname: Hermens
mesh_terms: D000327:Adsorption; D002244:Carbon / Q000737:chemistry; D002623:Chemistry Techniques, Analytical / Q000379:methods; D004129:Dimethylpolysiloxanes / Q000737:chemistry*; D004785:Environmental Pollutants; D006812:Humic Substances; D057927:Hydrophobic and Hydrophilic Interactions; D000442:Octanols / Q000737:chemistry; D011084:Polycyclic Aromatic Hydrocarbons / Q000737:chemistry*; D018570:Risk Assessment / Q000379:methods; D012995:Solubility; D014867:Water / Q000737:chemistry
chemical_list: D004129:Dimethylpolysiloxanes; D004785:Environmental Pollutants; D006812:Humic Substances; D000442:Octanols; D011084:Polycyclic Aromatic Hydrocarbons; D014867:Water; D002244:Carbon