peak resolution, R s

in chromatography
The separation of two peaks in terms of their average peak width at base (t R2 > t R1):
R s = t R2 − t R1 w b1 + w b2 2 = 2 ( t R2 − t R1 ) w b1 + w b2
In the case of two adjacent peaks it may be assumed that w b1 ≈ w b2, and thus, the width of the second peak may be substituted for the average value:
R s ≈ t R2 − t R1 w b2
PAC, 1993, 65, 819 (Nomenclature for chromatography (IUPAC Recommendations 1993)) on page 847
Orange Book, p. 108