Topics - Hydrophilic
There are three types of molecular interaction; those due to the generation of random paired charges throughout the molecule (Londons dispersion forces) and are thus called dispersive
interactions characterized by interaction between hydrocarbons; those due to interaction between permanent or induced dipoles called polar
interactions; and those due to interaction between permanent charges which are called ionic
interactions. These terms originated from physical chemistry. Similar terms were introduced in biochemistry and biology to describe the overall interactivity of bio-molecules that were large and contained many types of interactive groups. If the overall property of the molecule was hydrocarbon-like and interacted predominantly with other molecules dispersively the molecule was designated as hydrophobic
(fear of water
) as hydrocarbons and water were immiscible. If polar groups dominated in the macromolecule and so its interactivity was largely polar then the molecule was said to be hydrophilic
(love of water). Thus, hydrophobic interactivity is synonymous with dispersive interactivity and hydrophilic interactivity is synonymous with polar interactivity. In general the terms hydrophobic and hydrophilic are mostly used to describe the over all interactive property of a large molecule containing a range of interactive groups. They have been introduced into chromatography nomenclature but, on the whole, have tended to be more confusing than helpful.