Column Efficiency and Plate Heights in Unified Chromatography

5 COLUMN EFFICIENCY AND PLATE HEIGHTS IN UNIFIED CHROMATOGRAPHY 

The plate height in chromatography, H, is a useful indicator of the rate of peak broadening. The local plate height at any point on a column is given by the following  

There have been a few reports of column efficiency and reduced plate height measurements in several unified chromatography techniques. These have been based on the apparent plate height observed at the column outlet. In the notation used by Giddings (32) the apparent plate height, H, is given by the following  

This velocity gradient arises from the pressure gradient necessary to create mobile-phase flow. The pressure drops as we travel from the column inlet to the 

Expressing the averages in equation (7.4) with integrals, we obtain  

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