Plate Theory and Extensions - The Plate Theory > Page 6
Equating equations (3) and (5) and rearranging,
For mathematical convenience the variable will be changed, and the volume flow of mobile phase will be measured in units of (vm + Kvs) instead of ml.
Thus, the new variable (v) will be defined as,
The function (vm + Kvs) is termed the 'plate volume' and, thus, the column flow is measured in 'plate volumes' instead of milliliters. Another definition of the 'plate volume' is that volume of mobile phase that can contain all the solute in the plate at the equilibrium concentration of the solute in the mobile phase.
Substituting for dV from (8) in (6),