liquid-liquid extraction
This term may be used in place of liquid-liquid distribution when the emphasis is on the analyte(s) being distributed (or extracted).
The distinction between the @D01813@ (KD) and the @P04438@ (KDo) or the concentration distribution ratio  (Dc) is reaffirmed and it is recommended that the terms @P04438@, @P04437@ and @E02293@ constant should not be used as synonyms for the (analytical) @D01817@, Dc. A distinction is drawn between the terms solvent and diluent, and the term @E02299@ is now restricted to the active substance in the solvent (i.e. the homogeneous 'organic phase' which comprises the @E02299@, the diluent and/or the modifier) which is primarily responsible for the transfer of solute from the 'aqueous' to the 'organic' phase.
Orange Book, 2nd ed., p. 88 (