Plate Theory and Extensions - Vacancy Chromatography > Page 74


Consequently, the actual concentration of solute in the (n)th plate (XE) leaving the column and entering the detector that results from the injection of (p) plate volumes of pure mobile phase, followed by (v) plate volumes of equilibrated mobile phase carrying a solute concentration (Xo) of solute, will be given by

               .                (63)

The sum expressed by equation (63) also lends itself to a digital solution and with an appropriate computer program the actual peak profiles can be calculated for different volumes of pure mobile phase injected onto the equilibrated column. Values of (XE) were calculated for a column having 500 theoretical plates and for sample volumes of 20, 50, 100 and 200 plate volumes, respectively. The curves relating solute concentration (XE) to plate volumes of mobile phase passed through  the column are shown in Figure 19.