Comparatively Speaking: Solubility vs. Extraction

By: Anthony J. O'Lenick Jr., Siltech LLC

Posted: April 24, 2012

In this installment of "Comparatively Speaking," industry expert Tony O'Lenick describes the difference between solubility and extraction, and how various extraction techniques can be used to isolate desired cosmetic actives.

Solubility

As explained in a prior column, solubility is a term that relates to the ability of a material to dissolve in a given solvent. Solubility is never complete and results in the ability to partition materials into hydrophilic and hydrophobic systems. A simple example of separation by differences in solubility is shown by placing a mixture of salt and sand in water. The salt is dissolved and the sand remains behind.

Extraction

Extraction is a process that makes use of the fact that certain materials present in a substrate can be selectively dissolved into a particular solution. On major area currently employing this technique is naturals and botanicals, to obtain actives from plants. Extraction is a well-known technique for separating chemical constituents. It is a process by which a solute is extracted from a first solvent into a second solvent, where the two solvents are immiscible. One common extraction methodology used in organic chemistry involves combining, in a separatory funnel, water and diethyl ether.