Dispersion in Chromatography Columns - The Van Deemter Equation > Page 49

where, A=2ldp, B=2gDm 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