WATER SOLUBILITY AND OCTANOL WATER-PARTITIONING OF HYDROPHOBIC CHLORINATED ORGANIC-SUBSTANCES DETERMINED BY USING SPME/GC/

The critical step in the determination of water solubilitiy (S-W) and octanol-water partition coefficient (K-OW) of hydrophobic organic chem icals by using the generator-column technique and the slow-stirring pr ocedure, respectively, is the exact quantification of the low water-ph ase concentrations of the substances under investigation. We have test ed the applicability of solid-phase microextraction (SPME) and gas chr omatography with seven chlorinated organic compounds, The substances c over a S-W range from 500 mg/L to 7 ng/L and a log K-OW range from 3 t o 8. The results show that SPME can be a valuable alternative to commo n preconcentration techniques in the quantification of hydrophobic org anics in pure and octanol-saturated water, The apparent SPME distribut ion constants K-SPME (obtained with the 100 mu m-PDMS fiber for analyt e's partitioning between fiber coating and aqueous sample) do not corr elate directly with octanol/water partition coefficients and thus cann ot be recommended as a surrogate parameter for K-OW.