Frazer Parfum

Fragrances must be volatile to be perceived. Therefore, in addition to the nature of the functional groups and the molecular structure of a compound, the molecular mass is also an important factor. Molecular masses of ca. 200 occur relatively frequently; masses over 300 are an exception. Since fragrance materials differ in volatility, the odor of a perfume composition changes during evaporation, and is divided into the top note, the middle notes or heart, and the end note or dry down, which consists mainly of less volatile compounds. Odor perception also depends largely on odor intensity.

Therefore, the typical note is not determined only by the most volatile compounds. In some cases, substances (fixatives) are added to perfumes to prevent the more volatile components from evaporating too rapidly.