Factors controlling ion-exchange selectivity in suppressed ion chromatography

The control of ion-exchange selectivity is the most important means of moderating separations in suppressed ion chromatography. Selectivity variations are primarily achieved through the use of different stationary phases, hence the construction of the stationary phase plays a key role. The major factors which determine the selectivity of the ion-exchange phase are: the polymer composition of the stationary phase, the type of ion-exchange site and the structure of the ion-exchange site. The eluent can also play a significant role in determining the overall selectivity of an ion-exchange separation. The mobile phase parameters which affect the separation selectivity are: the choice of eluent ion, the concentration (and pH) of the eluent, the presence of non-ionic eluent modifiers and the eluent temperature. (C) 1997 Elsevier Science B.V.