CHROMATOGRAPHY OF CASTOR OIL IN LIPSTICK 315 Methyl Ricinoleate* The compound may be prepared from castor oil USP or technical grades of methyl ricinoleate* by following the procedure described in transesterification of the Sample, using a 1-g sample and 3 times the amount of transesterification reagent and extraction solvents. The' transesterification was carried out in a 250-ml boiling flask and the ex- tractions were made in 250-ml separatory funnels. The ether-extractable residue was reserved for purification by adsorption chromatography. A small glass wool plug was tamped into the bottom of a 24 X • in. i.d. glass chromatograph tube and the tube was filled with about 100 ml of CHCla. A slurry was made of 40 g of silica gel with 100 ml of CHCla, and half the slurry was poured into the chromatograph tube. The col- umn was packed by applying 5-6 lb of air pressure to the tube. In this and subsequent steps the solvent should not be permitted to drain below the surface of the silica gel. The remainder of the slurry was then packed as before. The reserved ether e•ctract was dissolved in 40 ml of hot CHCla and the solution was transferred to the chromatographic column. The beaker was rinsed with two 20-ml portions of CHCI• and the rinsings were added to the chromatographic column after the initial solution drained into the silica gel. Elutio.n was continued with 120 ml of CHCla and 200 ml (9 -• 1) of CHCla-ethyl ether (anhydrous). The CHCla eluate was discarded and the CHCla-ethyl ether eluate was collected in 25-ml t•ortions in tared 50-ml beakers. The collected CHCla-ethy] ether eluates were evaporated on the steam bath under a jet of air and the residues were heated at 105øC in a drying oven for 5 min. The residues were then cooled and weighed. The four largest residues were combined and rechromatographed by the previously described procedure. Again, the four largest residues were combined and reserved as "methyl ricinoleate standard." Transesterification Mix Methanol-benzene-concentrated sulfuric acid (3 -k 1 -k 0.037) was prepared fresh every 2 or 3 days. * HE 1821, Analabs, Inc., North Haven, Corm. 06473. ? It may be necessary to "transesterify" technical grades of methyl ricinoleate because they often con,tain unreacted glyceri. des.

316 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS Standard Solutions Separate standard solutions, 10 mg/ml, of methyl ricinoleate and di(2-ethylhexyl) phthal.ate • were prepared by accurately weighing 0.5 g of compound into a tared 50-ml volumetric flask and diluting to volume with benzene. Transesterification o[ the Sample A lipstick sample (200-300 mg) was accurately weighed into a tared 100-ml round-bottom boiling flask. Twenty milliliters off transesterifica- tion mix and three glass beads were added. The flask was connected to a water-jacketed reflux condenser with a 3r 24/40 male joint and the voltage on the power source attached to the heating mantle was set so that the solution in the flask woul.d boil gently. After the solution began to boil, refluxing was continued for 21/2 hours. The condenser was cooled, then rinsed with 10 ml of water. The transesterified sample plus water rinse were trans[ferred to a 125-ml separatory funnel. The condenser and boiling flask were rinsed with an additional 10 ml ot5 water which was then added to the separatory funnel. Both condenser and flask were rinsed with 25 ml ot5 ethyl ether (anhydrous) the rinsing was transferred to the [funnel, and shaken well. The lower aqueous layer was drawn off into a second 125-ml separatory funnel and extracted with 20 ml of the ether. The water layer was discarded. The two ether ex- tracts were then combined with a small amount of the ethyl ether used to rinse the extra separator. The combined extracts were washed with three 5-ml portions of water, and the aqueous wash discarded each time. The ether extracts were filtered through an ether-washed cotton plug into a 125-ml Erlenmeyer flask (or other suitable glassware). Next, the separa- tor was rinsed with two 5-ml portions of the ether and the rinsings were filtered through the cotton plug, which was then washed with 20 ml of an- hydrous ethyl ether. The ether was evaporated on the steam bath under a jet of air. (An air jet must be used when evaporating from an Erlen- meyer flask to prevent bumping and loss of sample.) The residue was reserved for gas chromatographic determination. Glc Determination of Methyl Ricinoleate The reserved ether-extractable residue was dissolved in 10 ml of ben- zene. One milliliter off di(2-ethylhexyl) phthalate internal standard solu- tion was added to the sample flask. Under the specified glc conditions, * "Flexol" DOP, Carbide & Carbon Chemicals Co., $0 E. 42nd St., New York, N.Y.