Plate Theory and Extensions - Vacancy Chromatography > Page 72

It follows that the concentration leaving the (n)th plate (XE) will be

 

                                                                                   

Employing the alternative Gaussian form of the elution equation,

                                           (61)

 

Furthermore, at the peak maximum when v=n  and  w=0,

                                                          (62)

 

Equation (62) shows that, when the charge is placed on the first plate, (Xn) can never equal zero and pure mobile phase free of solute will never elute from the column. However, in practice, it is impossible to place a sample exclusively on the first plate, and there must be a finite volume of mobile phase that will occupy a finite number of theoretical plates.