Applying a similar argument, to a TLC plate
The (Rf) value of a solute is given by
Now the distance (D) between two solutes (A) and (B) will be
D = Zs(B) - Zs(A)
= Zm(Rf(B) - Rf(A)) (14)
Now if the diameter of a spot is (d) then, [21]
or 
(15)
Now the diameter of the spot can be considered to be equivalent to (4s) and thus to achieve resolution, the spots must be separated by a distance equivalent to their diameter, then from equations (14) and (15)
Rearranging, and bearing in mind that 
where aB/A = Rf(B)/Rf(A) is the TLC equivalent to the separation ratio used in GC and LC.
Thus 
(16)
To increase the plate efficiency the particle size of the adsorbent must be reduced. In practice, the same plate adsorbent is employed and the phase system is adjusted to increase the value of (aAB).
