mass distribution ratio

in chromatography
https://doi.org/10.1351/goldbook.M03718
The fraction (\(1 - R\)) of a component in the stationary phase divided by the fraction (\(R\)) in the mobile phase: \[D_{\text{m}}=\frac{\text{amount of substance in the stationary phase}}{\text{amount of component in the mobile phase}}\] This term is recommended in preference to the term capacity factor frequently used in the chromatographic literature.
See also:
extraction factor
Sources:
Orange Book, 2nd ed., p. 107 [Terms]
PAC, 1993, 65, 2373. (Nomenclature for liquid-liquid distribution (solvent extraction) (IUPAC Recommendations 1993)) on page 2384 [Terms] [Paper]