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Toolbox: Validated Experimental Procedure for the...
Validated Experimental Procedure for the Determination of the Membrane/Water Partition Coefficient
Potential use:
Validated Experimental Procedure for the Determination of the Membrane/Water Partition Coefficient
Novelty and background:
In the recent years, the membrane/water partition coefficient Kmw has become a promising alternative approach to better mimic the biopartitioning of organic compounds in comparison to the traditionally applied octanol/water partition coefficient Kow. However, in contrast to the huge number of compounds with available experimental Kow data, the data base for the membrane/water partition coefficient is scarce (regarding data quantity and quality). Therefore, an efficient experimental procedure is needed for generating more reliable Kmw data. The scope and limitations of such a method as well as the reliability of results is demonstrated.
Description of tool:
Based on earlier published work the solid-phase microextraction (SPME) using commercially available polymer-coated quartz glass fibres was applied for the determination of the partitioning of test chemicals (from different compound classes) between aqueous solution and phosphatidylcholine vesicles. These results were compared with Kmw values obtained experimentally using the traditional methods equilibrium dialysis and ultracentrifugation. The SPME method is able to overcome limiting factors which restrict these traditional methods. It is easily to combine with gas and/or liquid chromatographic analysis. With different available fibre coatings and the possibility to sample from the headspace above the vesicle solution as well as directly immersed in the solution SPME allows measurements for a wide range of organic substances down to Kmw values of 10. 
The validated experimental procedure is ready for use. It can be established easily in any laboratory equipped with modern sample preparation tools and analytical instruments. A publication will be submitted soon.
Current state:
ready to use
Responsible scientists:
Gerrit Sch├╝├╝rmann, UFZ,
Related to deliverable: