## relative retardation, $$R_{\text{rel}}$$

in planar chromatography
https://doi.org/10.1351/goldbook.R05276
A term which is equivalent to relative retention used in @C01182@: the ratio of the $$R_{\text{F}}$$ value of a component to the $$R_{\text{F}}$$ value of a standard (reference) substance. Since the mobile phase front is common for the two components, the $$R_{\text{F}}$$ value can be expressed directly as the ratio of the distances travelled by the spot of the compound of interest ($$b_{i}$$) and the reference substance ($$b_{\text{st}}$$) respectively: $R_{\text{rel}}=\frac{R_{\text{F}\left(i\right)}}{R_{\text{F}\left(\text{st}\right)}}=\frac{b_{i}}{b_{\text{st}}}$ In former nomenclatures the symbol $$R_{\text{s}}$$ was used to express relative retardation in @P04682@. Because of its identity with the symbol for peak resolution the symbol $$R_{\text{rel}}$$ is suggested for relative retardation in @P04682@.
Source:
PAC, 1993, 65, 819. (Nomenclature for chromatography (IUPAC Recommendations 1993)) on page 845 [Terms] [Paper]