distribution isotherm

in chromatography
https://doi.org/10.1351/goldbook.DT06932
The equilibrium relation between the concentration of a sample component in the @S05949@ $$c_{\text{S}}$$, and in the @M03952@ $$c_{\text{M}}$$, expressed as a function $$c_{\text{S}}=f(c_{\text{M}})$$. In some versions of @C01075@, a distribution isotherm can be seen as a @PT06933@, an @AT06934@, or a combination of these, depending on the mechanism of separation.
Note:
The relation can be influenced also by concentrations of other sample components. $$c_{\text{S}}$$ and $$c_{\text{M}}$$ are usually expressed per unit volume of the phase; $$c_{\text{S}}$$ may also be expressed per mass of the dry solid phase or per unit surface area.
Source:
PAC, 1996, 68, 1591. (Nomenclature for non-linear chromatography (IUPAC Recommendations 1996)) on page 1592 [Terms] [Paper]
This definition supersedes an earlier definition of distribution isotherm.