The equivalent height of a theoretical plate H, as already defined (expression 1.5), is calculated for reference compounds to permit a comparison of columns of different lengths. H does not behave as a constant, its value depends upon the compound chosen and upon the experimental conditions.
For a long time in gas chromatography an adjustment value called the effective height of a theoretical plate Heff was calculated using the true efficiency. This corresponds to the Equation 1.14;
For a long time in gas chromatography an adjustment value called the effective height of a theoretical plate Heff was calculated using the true efficiency. This corresponds to the Equation 1.14;
In chromatography, in which the mobile phase is a liquid and the column is filled with spherical particles, the adjusted height of the plate h, is often encountered. This parameter takes into account the average diameter dm of the particles. This eliminates the effect of the particle size. Columns presenting the same ratio (length of the column)/(diameter of the particles) will yield similar performances.