Liquid-liquid extraction is based on the transfer of a solute substance from one liquid phase into another liquid phase according to the solubility.Extraction becomes a very useful tool if you choose a suitable extraction solvent. You can use extraction to separate a substance selectively from a mixture, or to remove unwanted impurities from a solution.
In the practical use, usually one phase is a water or water-based (aqueous) solution and the other an organic solvent (i.e. vegoil) which is immiscible with water.
In medicine, extraction is the surgical removal of a tooth from the mouth. Simple extractions may be done by a dentist; more complicated extractions are usually performed by an oral surgeon.