separation number, SN in chromatography

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