THE ISOLATION OF ESSENTIAL OILS - FACTORS INFLUENCING THE OIL COMPOSITION
A large number of plant species contain chemical compounds which can be isolated as an essential oil. Different methods are used to isolate these oils from the various plant materials. Although it seems relatively simple to isolate such oils, the composition of an oil may vary to a large extent depending on the isolation method used. The advantages and disadvantages of some isolation methods such as hydrodistillation, solvent extraction, and simultaneous distillation-extraction are discussed in this paper. Some attention is also paid to relatively new methods of isolation, such as extraction by supercritical carbon dioxide, and the use of microwave ovens.
In addition, some examples are given to illustrate that the moment of sampling of the plant material may also have a large influence on the composition of the essential oil isolated.
Scheffer, J.J.C. (1993). THE ISOLATION OF ESSENTIAL OILS - FACTORS INFLUENCING THE OIL COMPOSITION. Acta Hortic. 344, 2-8
Hydrodistillation, Distillation-extraction, Solvent extraction, Supercritical fluid extraction, Microwave heating, Seasonal variation