separation number, SN in chromatography, in liquid-liquid distribution, in chromatography

https://dx.doi.org/10.1351/goldbook.S05616
This expresses the number of peaks which can be resolved in a given part of the chromatogram between the peaks of two consecutive n-alkanes with z and (z + 1) carbon atoms in their molecules:
SN = t R z + 1 − t R z w h z + w h z + 1 − 1
In the German literature the symbol TZ (trennzahl) is commonly used to express the separation number. As the separation number depends on the n-alkanes used for the calculation, they always must be specified with any given SN value.
Source:
PAC, 1993, 65, 819 (Nomenclature for chromatography (IUPAC Recommendations 1993)) on page 847