Anal. Chem. 1996, 68, 130-133
Solid-Phase Microextraction as a Method for Estimating the Octanol-Water Partition Coefficient John R. Dean,*,† William R. Tomlinson,† Valeriya Makovskaya,† Robert Cumming,‡ Malcolm Hetheridge,‡ and Michael Comber‡
Department of Chemical and Life Sciences, Ellison Building, University of Northumbria at Newcastle, Newcastle upon Tyne, Tyne and Wear NE1 8ST, U.K., and Brixham Environmental Laboratory, Zeneca Ltd., Freshwater Quarry, Brixham, Devon TQ5 8BA, U.K.
The determination of octanol-water partition coefficients (log Kow) is important for the prediction of the fate of organic pollutants in the environment. Traditionally, log Kow values are determined by shake-flask, estimated by, e.g., HPLC retention data, or calculated, e.g., from ClogP. In this paper, an alternative approach is reported that allows log Kow to be estimated from solid-phase microextraction (SPME) data. Previously reported attempts to correlate SPME data with log Kow are discussed. The results obtained in this work for six phenols, using an 85 µm polyacrylate-coated fiber, indicate that SPME is a viable method for estimating log Kow values 3.5. Further work should be carried out with alternative fibers and fibers with thicker coatings. CONCLUSIONS The use of SPME for determining distribution coefficient, K, values for a range of phenols has been reported. The determined (31) Makovskaya, V.; Dean, J. R.; Tomlinson, W. R.; Comber, M. Anal. Chim. Acta 1995, 315, 193.
K values correlate well with octanol-water partition coefficient data for K < 3.5. In addition, the time scale to reach equilibrium (up to 20 h) could be reduced if the samples were stirred in situ. It is envisaged that the incorporation of a microstirrer below the sample vial would significantly reduce the time to reach equilibrium. It is expected that this facility will be available on commercial instruments in the near future. ACKNOWLEDGMENT Brixham Environmental Laboratory gratefully acknowledges the loan of the automated SPME system from Varian U.K. Received for review August 2, 1995. Accepted October 16, 1995.X AC950778G X
Abstract published in Advance ACS Abstracts, December 1, 1995.
Analytical Chemistry, Vol. 68, No. 1, January 1, 1996
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