Dividing through by (n), noting that , and rearranging,

            

Replacing the geometric series by the expression for its sum,

                                       (76)

Rearranging to provide an expression for (r )

                         (77)

It is clear from equation (77) that the peak capacity is controlled by the column efficiency and the capacity ratio of the last eluted peak.  The peak capacities of a series of columns having different efficiencies were calculated for a range of peak capacity ratios employing equation (77). The results are shown as curves relating peak capacity to capacity ratio in Figure 25.