distribution isotherm

in chromatography
The equilibrium relation between the concentration of a sample component in the stationary phasec S, and in the mobile phasec M, expressed as a function c S = f c M.
Note:
The relation can be influenced also by concentrations of other sample components. c S and c M are usually expressed per unit volume of the phase; c S may also be expressed per mass of the dry solid phase or per unit surface area.
In some versions of chromatography, a distribution isotherm can be seen as a partition isotherm, an adsorption isotherm, or a combination of these, depending on the mechanism of separation.
Source:
PAC, 1996, 68, 1591 (Nomenclature for non-linear chromatography (IUPAC Recommendations 1996)) on page 1592
This definition supersedes an earlier definition of distribution isotherm.