Page 17 - Pharmd general phytochemistry I-Final2024_LEUCTERS

5. SUPERCRITICAL METHOD

Supercritical fluid extraction (SFE)
Separating any essential oil from the matrix using supercritical fluid as
extracting solvent, ex. SC CO2.

Examination of V.O.:
• To evaluate the quality of the plant species as well as the raw material
which will be used in commercial preparations.
• To differentiate between genuine and adulterated oil.
• Physical examination of volatile oil is very important.

Physical methods of examination of V.O.:

1- Color:
Most oils are colorless when pure and fresh. Upon exposure to the air
they acquire various colors. Volatile oils can be made colorless by re-
distillation (Rectification).
The blue color of oil of chamomile is an inherent property of the oil even
when freshly distilled and said to be due to the highly unsaturated
hydrocarbon called Chamazulene.

2- Specific gravity:
Gives an indication about the composition of the volatile oil.
Those oils which are lighter than water, ex. caraway, coriander, orange,
lemon, and turpentine oils, are usually rich in hydrocarbons (aliphatic),
alcohols, esters and ketones.

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