Chromatographic properties plate height

The peak dispersion in chromatography is generally characterized by the theoretical plate height (H) and the number of theoretical plates (N). The treatment of the mass transfer processes and the distribution equilibrium between the mobile and stationary phase in a column lead to equations that link the theoretical plate height as the crucial column performance parameter to the properties of the chromatographic systems, such as the linear velocity of the mobile phase, the viscosity, the diflusion coefficient of analyte, the retention coefficient of analyte, column porosity, etc. 

Generally the H-u or h-v plots are used to compare the kinetic efficiency of the chromatographic columns. Figure 5.1 demonstrates an example of h-v plots of different type modern stationary phases. The characteristic properties of these plots are the minimum plate height value (Hmin or fimin) and the observed optimum in linear velocity Uopt or Vopt). The position of the minimum on the H-u, or h-v curve, and the optimum linear velocity can be determined by the use of differential calculus. The optimum linear velocity occurs when the slope of the H (or h) versus u (or v) curve is zero—that is, when dH/du = 0 (or dh/dv = 0). This condition is satisfied in the van Deemter form when ... 

---