Solid-phase microextraction fibre-water distribution constants of more hydrophobic organic compounds and their correlations with octanol-water partition coefficients

Fibre coating-water distribution constants (K,,) of more hydrophobic chemicals were determined with six different solid-phase microextraction fibre types (including a polyoctylmethylsiloxane (C,) prototype) by fibre exposure to agitated large-volume water samples lasting several days. The results obtained are comparable with K-fw values obtained under dynamic conditions. Octanol-water partition coefficients (K-OW) were measured with the mixture of distributing substances to examine log K-fw-log K-OW relationships based on a consistent dataset. K-fw values obtained with liquid polymer fibre coatings correlate reasonably well with the hydrophobicity of the test compounds (with decreasing sensitivity in the following order: 7 mum polydimethylsiloxane (PDMS)>100 mum PDMS>C8>polyacrylate) whereas this is not the case with the PDMS-divinylbenzene (DVB) and Carbowax-DVB fibres, partially porous coatings which provide the highest Kfw values for all substances tested. (C) 2003 Elsevier Science B.V. All rights reserved.