Castor Oil Emulsion
Castor Oil Emulsion contains NLT 90.0% and NMT 120.0% of the labeled amount of Castor Oil.
Sample: 10 mL of Emulsion well shaken
Analysis: Transfer the Sample to a 125-mL separator. Add 10 mL of 1 N hydrochloric acid and 20 mL of solvent hexane. Shake vigorously for 23 min, allow the layers to separate, discard the aqueous phase, and filter the upper layer through anhydrous sodium sulfate into a small beaker. Evaporate the solvent on a steam bath, and to the residue add 12 drops of sulfuric acid.
Acceptance criteria: A red color indicates the presence of castor oil.
Internal standard solution: 12 mg/mL of di(2-ethylhexyl)phthalate in chloroform
Standard solution: Transfer 100 mg of castor oil to a 100-mL boiling flask equipped with a suitable reflux condenser connected by a ground-glass joint. Add 30 mL of a mixture of 300 mL of methanol and 3.7 mL of sulfuric acid, reflux in a water bath maintained at 7580 for 2.5 h, cool, and rinse down the condenser with 10 mL of water. Transfer the contents of the flask to a 125-mL separator with the aid of 10 mL of water. Rinse the condenser and the flask with 25 mL of solvent hexane, and transfer to the separator. Shake the separator for 2 min, and draw off the aqueous layer into a second 125-mL separator. Add 20 mL of solvent hexane to the second separator, shake for 2 min, discard the aqueous layer, and transfer the solvent hexane layer to the first separator with the aid of 10 mL of solvent hexane. Wash the combined extracts with three 5-mL portions of water, discarding the washings, and transfer the washed extract to a 125-mL conical flask through a funnel containing anhydrous sodium sulfate, with the aid of 25 mL of solvent hexane. Place the flask in a hot water bath, and evaporate with the aid of a current of air to dryness. To the residue add 10.0 mL of Internal standard solution, and mix until solution is complete.
Sample solution: Transfer an amount of Emulsion, well-shaken and nominally equivalent to 100 mg of castor oil, to a long-neck, round-bottom 100-mL boiling flask equipped with a suitable reflux condenser connected by a ground-glass joint. Prepare as directed in Standard solution, beginning with Add 30 mL of a mixture of 300 mL of methanol and 3.7 mL of sulfuric acid.
Detector: Flame ionization
Column: 1.8-m × 4-mm; packed with 4% liquid phase G25 on support S1
Column conditioning: Flush with helium for 25 min, then heat without further flushing at 250 for NLT 30 min, then cool to room temperature, and finally heat while helium is flowing through it at 250 for NLT 60 min.
Flow rate: Adjust to obtain a peak due to castor oil 5.5 min after introduction of the specimen and an internal standard peak 8 min after introduction of the specimen.
Carrier gas: Helium
Injection size: 5 µL
Samples: Standard solution and Sample solution
Measure the heights of the peaks due to castor oil and the internal standard.
Calculate the percentage of castor oil in the portion of Emulsion taken:
Result = (RU/RS) × (WS/WU) × 100
Acceptance criteria: 90.0%120.0%
• Packaging and Storage: Preserve in tight containers.