Finite charge, elution curve

In the development of the plate theory and the derivation of the equation for the elution curve of a solute, it was assumed that the initial charge was located In the first plate of the column. In practice, this is difficult to achieve, and any charge will, in fact, occupy a finite column volume and consequently a specific number of the first theoretical plates of the column. Consider the situation depicted in figure 1 where the initial charge is distributed over (r) theoretical plates. 

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