The Mechanism of Chromatographic Retention - Chromatographic Interactions > Dispersive Interactions > Page 6

 

It is important to emphasize that there is no localized charge on the molecule that causes dispersive interaction. Dispersive interactions arise from a host of randomly placed fluctuating charges that at any instant can interact with similar randomly placed charges on the complementary interacting molecule.

As already stated, all molecules can interact dispersively with another molecule and such interaction will occur independently of any other interactive mechanism that might be taking place. Dispersive interaction may be exclusive and dominant as in the case of one hydrocarbon interacting with another hydrocarbon or can be marginal as in the case of water interacting with methanol.

Courtesy of Mr. Andrew Lynn of the Dexsil Corporation

Figure 2 The Separation of a Sample of Gasoline on a Capillary Column Coated with a Polar and a Dispersive Stationary Phase