Peanut Oil
» Peanut Oil is the fully-refined (alkali-refined, bleached, and deodorized at 230 to 260) oil obtained from the seed kernels of one or more of the cultivated varieties of Arachis hypogaea Linné (Fam. Leguminosae).
Packaging and storage— Preserve in tight, light-resistant containers, and prevent exposure to excessive heat.
Identification— Saponify 5 g by boiling with 2.5 mL of 7.5 N sodium hydroxide and 12.5 mL of alcohol. Evaporate the alcohol, dissolve the soap in 50 mL of hot water, and add hydrochloric acid until the free fatty acids separate as an oily layer. Cool the mixture, and remove the separated fatty acids and dissolve them in 75 mL of ether. To the ether solution add a hot solution of 4 g of lead acetate in 40 mL of alcohol, and allow the mixture to stand for 18 hours. Filter the supernatant, and transfer the precipitate to the filter with the aid of ether. Place the precipitate in a mixture of 40 mL of 3 N hydrochloric acid and 20 mL of water, and heat until the oily layer is entirely clear. Cool, decant the water solution, and boil the fatty acids with water that has been acidified with hydrochloric acid, until free from lead. (The fatty acids are free from lead when 100 mg, dissolved in 10 mL of alcohol, is not darkened by the addition of 2 drops of sodium sulfide TS.) Allow the fatty acids to solidify, and press them dry between filter papers on a cold surface. Dissolve the solid fatty acids in 25 mL of 90 percent alcohol, by heating gently, then cool to 15 and maintain at that temperature until the fatty acids have crystallized. Filter the separated fatty acids, recrystallize them from hot 90 percent alcohol, and dry in a vacuum desiccator for 4 hours: the arachidic acid so obtained melts between 73 and 76.
Specific gravity 841: between 0.912 and 0.920.
Cottonseed oil— Mix 5 mL in a test tube with 5 mL of a mixture of equal volumes of amyl alcohol and a 1 in 100 solution of sulfur in carbon disulfide, warm the mixture carefully until the carbon disulfide is expelled, and immerse the test tube to one-third of its length in a boiling, saturated solution of sodium chloride: no reddish color develops within 15 minutes.
Rancidity— Shake 1 mL of a 1 in 10 solution of Peanut Oil in ether with 1 mL of hydrochloric acid, and add 1 mL of a 1 in 1000 solution of phloroglucinol in ether: no red or pink color develops.
Solidification range of fatty acids 401 The dry mixed fatty acids of it solidify between 26 and 33.
Free fatty acids 401 The free fatty acids in 10 g require for neutralization not more than 2.0 mL of 0.020 N sodium hydroxide.
Iodine value 401: between 84 and 100.
Saponification value 401: between 185 and 195.
Unsaponifiable matter 401: not more than 1.5%.
Refractive index 831: between 1.462 and 1.464 at 40.
Auxiliary Information— Please check for your question in the FAQs before contacting USP.
Topic/Question Contact Expert Committee
Monograph Hong Wang, Ph.D.
(EM205) Excipient Monographs 2
USP32–NF27 Page 1297
Pharmacopeial Forum: Volume No. 34(6) Page 1525
Chromatographic Column—
Chromatographic columns text is not derived from, and not part of, USP 32 or NF 27.