COMPARISON OF HYDRODISTILLATION AND SUPERCRITICAL FLUID EXTRACTION FOR THE DETERMINATION OF ESSENTIAL OILS IN AROMATIC PLANTS

Supercritical fluid extraction (SFE) and hydrodistillation were compared as methods to extract essential oils from savory, peppermint and dragonhead. Despite the high solubilities of essential oil components in supercritical CO2, the extraction rates were relatively slow with pure CO2 (ca. 80% recovery after 90 min). However, a 15-min static extraction with methylene chloride as modifier followed by a 15-min dynamic extraction with pure CO2 yielded high recoveries which agreed well with the results of hydrodistillation performed for 4 h. Spike recovery studies demonstrated that compounds as volatile as monoterpenes can be quantitatively (>90%) collected off-line from the SFE effluent. SFE recovered some organic compounds from each of the samples that were not extracted by hydrodistillation, most notably C27, C29, C31, and C33 n-alkanes.