A: Shake 5mLwith 5mLof sodium hydroxide TS:the volume of Eucalyptol is not diminished.

B: Shake 1mLwith 20mLof water,and allow the liquids to separate.To 10mLof the water layer,add 1drop of ferric chloride TS:the mixture develops no violet color.

Assay preparation— Transfer about 90mg of eucalyptol,accurately weighed,to a 100-mLvolumetric flask,dilute with methanol to volume,and mix.

System suitability solution— Prepare a solution of limonene and eucalyptol in methanol containing 0.2mg per mLand 0.9mg per mL,respectively.

Chromatographic system (see Chromatography á621ñ)—The gas chromatograph is equipped with a flame-ionization detector and a 0.32-mm ×60-m fused-silica capillary column coated with phase G16.The temperatures of the injection port and the detector block are maintained at 250.The carrier gas is helium adjusted to a column head pressure of 30psi.The split flow rate is about 50mLper minute.The column temperature is initially maintained at 60,then increased to 200at the rate of 6per minute,beginning at the time of injection.Chromatograph the System suitability solution,and record the peak responses as directed for Procedure:the resolution,R,between limonene and eucalyptol is not less than 2.0;and the column efficiency determined from the eucalyptol peak is not less than 150,000theoretical plates.

Procedure— Separately inject equal volumes (about 1µL)of the Assay preparationand of methanol into the chromatograph,record the chromatograms,and measure the areas of the peaks.Identify by their retention times any peaks present in the chromatogram obtained from the Assay preparationthat correspond to those in the chromatogram of methanol.Calculate the percentage of C10H18Oin the portion of Eucalyptol taken by the formula: in which rUis the eucalyptol peak response obtained from the Assay preparation;and rTis the sum of the peak responses obtained from the Assay preparation,other than the responses corresponding to those in the chromatogram of methanol.