where, A=2ld_p, B=2gD_m and

 

Equation (33) is a hyperbolic function which has a minimum value of (H) for a particular value of (u). Thus, a maximum efficiency will obtained at a particular linear mobile phase velocity.

An example of an HETP curve obtained in practice showing this hyperbolic relationship is given in figure 11.

 

 

Figure 11. HETP Curve for Hexamethylbenzene