Eucalyptol
(ue'' ka lip' tol).
Click to View Image

C10H18O 154.25
1,3,3-Trimethyl-2-oxabicyclo[2.2.2]octane;    
1,8-Epoxy-p-menthane     [470-82-6].
DEFINITION
Eucalyptol is obtained from oil of eucalyptus and from other sources. It contains NLT 98.0% and NMT 100.0% of C10H18O.
IDENTIFICATION
•  Add 1 mL of phosphoric acid to 1 mL of Eucalyptol contained in a test tube maintained in an ice bath. A solid white crystalline mass is formed, from which eucalyptol separates upon addition of warm water.
ASSAY
•  Procedure
System suitability solution:  0.2 mg/mL of limonene and 0.9 mg/mL of eucalyptol in methanol
Sample solution:  0.9 mg/mL of eucalyptol in methanol
Blank:  Methanol
Chromatographic system 
Mode:  GC
Detector:  Flame ionization
Column:  0.32-mm × 60-m fused-silica capillary column coated with phase G16
Temperature:  See Table 1.
Table 1
Initial
Temperature
()
Temperature
Ramp
(/min)
Final
Temperature
()
Hold Time at Final
Temperature
(min)
60 6 200
Injector port temperature:  250
Detector temperature:  250
Split flow rate:  50 mL/min
Carrier gas:  Helium
Column head pressure:  30 psi
Injection size:  1 µL
System suitability 
Sample:  System suitability solution
Suitability requirements 
Resolution:  NLT 2.0 between limonene and eucalyptol
Column efficiency:  NLT 150,000 theoretical plates, eucalyptol
Analysis 
Samples:  Sample solution and Blank
[Note—Identify any peaks from the Sample solution, that correspond to those in the Blank, by their retention times. ]
Calculate the percentage of eucalyptol (C10H18O) in the portion of Eucalyptol taken:
Result = (rU/rT) × 100
rU== peak response of eucalyptol from the Sample solution
rT== sum of all peak responses from the Sample solution, other than the responses corresponding to those of the Blank
Acceptance criteria:  98.0%–100.0%
IMPURITIES
•  Limit of Phenols
Analysis 1:  Shake 5 mL with 5 mL of sodium hydroxide TS.
Acceptance criteria 1:  The volume of Eucalyptol is not diminished.
Analysis 2:  Shake 1 mL with 20 mL of water, and allow the liquids to separate. To 10 mL of the water layer, add 1 drop of ferric chloride TS.
Acceptance criteria 2:  The mixture develops no violet color.
SPECIFIC TESTS
•  Specific Gravity 841: 0.921–0.924
•  Distilling Range, Method I 721: 174–177
•  Refractive Index 831: 1.455–1.460 at 20
ADDITIONAL REQUIREMENTS
•  Packaging and Storage: Preserve in tight containers.
Auxiliary Information— Please check for your question in the FAQs before contacting USP.
Topic/Question Contact Expert Committee
Monograph Clydewyn M. Anthony, Ph.D.
Senior Scientific Liaison
1-301-816-8139
(SM22010) Monographs - Small Molecules 2
USP35–NF30 Page 3149
Pharmacopeial Forum: Volume No. 37(2)