Study Set Content:
REFRACTIVE INDEX
o varies from
1.42 to 1.61
o mostly characterized by
high refractive indices
Detection: The pure authentic volatile oils have _____ as specified in the official compendia, whereas the adulterated oils will show _____
definite refractive index, different values
OPTICAL ROTATION o large number of volatile oils exhibit optical activity by virtue of the chemical constitution of the
oil(s).
gives some vital information with regards to the source and authenticity of the oil sample.
Optical rotation
SPECIFIC GRAVITY
o ranges from
0.8 to 1.17
SOLUBILITY o majority of volatile oils are immiscible with
water
soluble in absolute alcohol and several other organic solvents e.g.,
ether, chloroform, carbon disulfide, acetone, hexane, ethyl acetate.
CLASSIFICATION OF VOLATILE OILS
✓ Alcohol ✓ Aldehydes ✓ Hydrocarbons ✓ Ketones ✓ Esters ✓ Oxides ✓ Phenols ✓ Phenolic esthers
METHODS USED IN OBTAINING VOLATILE OILS
Distillation
Expression and Ecuelle Method
Extraction
Enzymatic hydrolysis
Enfleurage
Destructive distillation
: most effective
(Direct steam distillation
(most common
Expression and Ecuelle Method
most expensive
Extraction
(time consuming
Enzymatic hydrolysis
METHODS USED TO EXTRACT OFFICIAL VOLATILE OILS
➢ Steam Distillation
➢ Expression
Star Anise Oi
Illicium verum
Rose Oil
Rosa gallica/ rosa alba
Peppermint Oil
Mentha piperita
Orange Oil
Citrus sinensis
Lemon Oil
Citrus limon
