Plate Theory and Extensions - Resolving Power of a Column > Page 59

It will be seen in The Thermodynamics of Chromatography , that two adjacent peaks are not likely to have precisely the same peak widths (i.e., exhibit the same efficiency). Nevertheless, in most practical examples, the difference will be small and tend to be negligible. In view of this, the widths of closely adjacent peaks will be assumed to be the same.

Consider the two peaks in Figure 17. The difference between the peaks, for solutes (A) and (B), measured in volume flow of mobile phase is,


           n(vm +KBvS) - n(vm +KAvS) = n(KB + KA)vS              (53)


As the widths of the two peaks are assumed to be the same, then the peak width in volume flow of mobile phase will be


                              2s = 2(vm +KAvS)                              (54)