retardation factor, R in column chromatography, in analysis, in planar chromatography

https://dx.doi.org/10.1351/goldbook.R05352
The fraction of the sample component in the mobile phase at equilibrium; it is related to the retention factor and other fundamental chromatography terms:
R = 1 k + 1
Source:
PAC, 1993, 65, 819 (Nomenclature for chromatography (IUPAC Recommendations 1993)) on page 843