Purnell equation

The Purnell equation is an equation used in analytical chemistry to calculate the resolution Rs between two peaks in a chromatogram.
 * $$R_s = \frac{\sqrt{N_2}}{4} \left ( \frac{\alpha - 1}{\alpha} \right ) \left ( \frac{k'_2}{1 + k'_2} \right )$$

where
 * Rs is the resolution between the two peaks


 * N2 is the plate number of the second peak


 * α is the separation factor between the two peaks


 * k '2 is the retention factor of the second peak.

The higher the resolution, the better the separation.