From the Plate
Theory (see
The Plate Theory and Extensions
), 
, where (Vm) is the total volume of mobile
phase in the column or the column dead volume.
Thus: 
Now: 
| where (r) | is the radius of the column, |
| (L) | is the length of the column, |
| (e) | is the fraction of the column containing solvent. |
Thus: 
Now (e) can be taken as approximately 0.6:
Thus, 
and: 
(1)
The magnitude of (Av) will be determined by the nature of the separation, and (Am) will be defined by the loading capacity of the stationary phase and, to some extent, by the shape of the adsorption isotherm.
