and the capacity ratio (k'_a) will be given by,

                                                              (37)

For two enantiomers (a) and (b), enantiomer (b) being the last eluted peak, the separation ratio (a_ba) is given by,

                                                                       (38)

The efficiency (n), required to achieve a separation (i.e. the solutes are separated by (6s) is given by the Purnell equation (14) (see book 6 of this series)

                                                                  (39)

where (k_a) is the capacity ratio of the first eluted peak and (a_ba) is the separation ratio or the two peaks (i.e. a_ba = k'_b/k'_a).