Clove Oil
(klove oyl).
Clove Oil is the volatile oil distilled with steam from the dried flower buds of Syzygium aromaticum (L.) Merr. and L. M. Perry (Fam. Myrtaceae). It contains NLT 85.0% of total phenolic substances, chiefly eugenol (C10H12O2).
•  Procedure
Sample:  10 mL of Clove Oil
Analysis:  Pipet the Sample into a suitable cassia flask, the neck of which is graduated from 0–6 mL at intervals of 0.1 mL. Add 75 mL of 1 N potassium hydroxide, and shake the mixture for 5 min. Heat for 10 min in boiling water, shaking the flask at least 3 times during the heating. Remove the flask from the bath, and cool to room temperature. When the liquids have separated completely, add sufficient 1 N potassium hydroxide to raise the lower level of the oily layer so that it is within the graduated portion of the neck. Measure the volume of the oily layer after standing for 18 h.
Acceptance criteria:  NMT 1.5 mL, indicating the presence of NLT 85.0%, by volume, of total phenolic substances in the Oil
•  Heavy Metals, Method II 231: NMT 40 µg/g
•  Limit of Phenol
Sample:  1 mL of Clove Oil
Analysis:  Shake the Sample with 20 mL of hot water: the water shows not more than a scarcely perceptible acid reaction with blue litmus paper. Cool the mixture, pass the water layer through a wetted filter, and treat the clear filtrate with 1 drop of ferric chloride TS.
Acceptance criteria:  The mixture exhibits only a transient, grayish-green color, but not a blue or violet color.
•  Specific Gravity 841: 1.038–1.060
•  Optical Rotation, Angular Rotation 781A: It is optically inactive or slightly levorotatory. The angular rotation is not grater than 1.5.
•  Refractive Index 831: 1.527–1.535 at 20
•  Solubility in 70% Alcohol: One volume dissolves in 2 volumes of 70% alcohol.
•  Packaging and Storage: Preserve in well-filled, tight containers, and avoid exposure to excessive heat.
•  Labeling: The label states the Latin binomial name and, following the official name, the part of the plant source from which the article was derived.
Auxiliary Information— Please check for your question in the FAQs before contacting USP.
Topic/Question Contact Expert Committee
Monograph Maged H. Sharaf, Ph.D.
Principal Scientific Liaison
(DS2010) Monographs - Dietary Supplements
USP35–NF30 Page 1760
Pharmacopeial Forum: Volume No. 27(4) Page 2796