Solvent extraction of metal complexes

The pH-metric technique used to determine partition coefficients was first used in the 1950s in solvent extraction of metal complexes [280-282], but it is in pharmaceutical research that it is most widely used thanks to the recent development of a fully automated and computer-controlled apparatus [125,283]. The potentiometric approach has been validated in various solvent systems [284-287], and it has become a relevant and expanding experimental technique to obtain lipophilicity descriptors [257,287-289]. 

V. Marcus and A. S. Kertes, Ion Exchange and Solvent Extraction of Metal Complexes, Wiley-Intersdence, New York, 1969. 

This example indicates that in solvent extraction of metal complexes with acidic ligands, it can be more advantageous to plot log D vs. log[A ], rather than against pH, which is the more common (and easy) technique. 

Marcus, Y. and Kertes, A.S., Ion exchange and solvent extraction of metal complexes, Wiley-interscience, London, 1970. 

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