Topics - Ionic Interactions
There are three forms of molecular interaction, dispersive interactions that result from statistically generated temporary dipoles (Londons dispersion forces), polar interactions that occur between permanent and induced dipoles and ionic interactions that result from interaction between molecular groups that contain net permanent opposite charges. Only dispersive interaction can occur to the exclusion of all others, ionic interactions are usually accompanied by polar interactions and always by dispersive interactions. Ionic interactions are exploited in ion chromatography. The stationary phase is arranged to contain counter-ions to the solute ions and, thus, interaction occurs and the ionic solutes are retained. The strength of the net retentive ionic interaction can be modified by adjusting the ionic character of the mobile phase and allow competitive ion interactivity for the solute between the two phases.