Jour. Pharm , 1869 4. A higher percentage of free acid; to this is due the discordant figures gotten for the temperature-turbidity, but by an examination of these figures it appears that every per cent. of free acid in the oil reduces the temperature about 3° C.; if such a correction be made, figures near 85 are gotten. 5. A higher iodine-absorption for the native oil; this is very probably due to the presence of more olein than in the European oils, the melting point of the fatty acids also indicating this. There is another instance known, similar to this one, in which it has been proven that American fats differ in important respects from the same European fats; refererence is made to lard. American lard has an iodineabsorption of from 60 to 62 per cent., English lard from 51.5 to 62 per cent. (AM. JOUR. OF PHARM., 1888, 574 and 578.) From such results it would appear that climate and soil modify considerably the composition of the fats and oils, and for such variations due allowance must be made. 6. The fatty acids of the American oils at a temperature of 20° C. are viscid fluids containing suspended the higher melting acids; the European oils are solid at this temperature. Under the microscope, . Jour. . May, 1889 the former shows the same structure, long prisms, but the European oils differ considerably in appearance-a globular form predominating; they all polarize light. For the examination of olive oil, the specific gravity, elaidinreaction, iodine-absorption and fusing point of the fatty acids should be considered; in an adulterated oil all of these tests will tend to confirm the adulteration and will give valuable clues to the nature of the adulterant. EXPRESSED OIL OF ALMONDS. BY GEORGE M. BERINGER, PH. G. Read at the Pharmaceutical Meeting, April 16. The examination of a number of samples of oil of almonds was undertaken by the writer with a two-fold object in view; first, to determine the purity of the commercial oils, and, secondly, to satisfy myself as to the value of the requirements and tests of the United States and German Pharmacopoeias. The samples of oil examined were obtained from prominent dealers in New York and Philadelphia (most of them being samples of products offered for sale), and as received they varied in amount from two fluid drachms in one case, to a pint in several. The oils examined are believed to represent those now in the market. For comparison, samples of pure oil were prepared by extracting bitter and sweet almonds with petroleum ether. The bitter yielded 46 per cent.; the sweet 50 per cent. It was intended also to prepare a sample of peach-kernel oil, but I could not at this time procure the kernels. I regret that the samples in most cases were so small that they were insufficient to permit of the application of a number of tests. Specific Gravity.-The U. S. Pharmacopoeia states the specific gravity at 914 to 920. The German Pharmacopoeia as ·915 to ·920. The British Pharmacopoeia is silent as to specific gravity, and gives, likewise, no tests. Watts' dictionary quotes Cloëz as authority for its statement of 91844. Gmelin, vol. xvii., 92, gives the following: 911 (Brandes); 917 (Brisson); 918 at 15° (Schübler). Allen (Commercial Organic Analysis, vol. ii) states the specific gravity as 914 to 918. Brannt (Animal and Vegetable Fats and Oils) places it at 917 at 68° F., and 919 at 59° F. Bornemann (Die fetten Oele) gives 917 to 920 at 15° C. The specific gravities of the samples were carefully taken at 60° F., Jour. Pharm , 1889 using, where the sample permitted, a 50-gm. bottle; where the sample was small a 10-gm. bottle was used. The following table exhibits the gravities and physical characters of the samples: As from the tests, numbers 1, 3 and 12 of the commercial samples are believed to be pure, and with numbers 13 and 14 prepared by myself, showing a range of gravity from .9167 to.9185, it is believed that the officinal limit might be still further narrowed by fixing the gravity at .916 to .919 and usually about 918. Solubility. Considerable discrepancy exists in the various statements regarding the solubility. The U. S. Pharmacopoeia describes almond oil as slightly soluble in alcohol. Gmelin's Chemistry (vol. xvii, 93) states "almond oil dissolves in about 25 parts of cold and 6 parts of hot alcohol, (Pfaff); according to Brande it dissolves very slightly in alcohol of 0.82 sp. gr. Storer's Dictionary of Solubilities says, "soluble in 25 parts of cold and 6 parts of boiling alcohol. 1000 drops of alcohol of .823 dissolve 3 drops of it at 12.5° (Schubarth's Tech. Chem.)." Allen (Commercial Organic Analysis, vol. II) says "soluble in 6 parts of boiling and 24 parts of cold alcohol." Brannt (Animal and Vegetable Fats & Oils) states "soluble in 60 parts of cold and 15 parts of boiling alcohol." The earlier editions of the National Dispensatory stated "soluble in about 30 parts of absolute alcohol," which statement, although probably correct, has been omitted in the recent editions. My own experiments lead to the Jour. Pharm May, 1889 following statement: On mixing one part of oil of almonds with four parts of absolute alcohol and immersing the test tube in the water-bath a perfectly clear solution is obtained. It required 34 parts of cold absolute alcohol at the temperature of the atmosphere (about 70° F.) to make a perfect solution. With alcohol of .820 sp. gr., 42 parts were required to make a solution at the boiling point. Color Reactions.-The U. S. P. gives only the reaction with sulphuric acid. While this test may serve to. indicate the adulteration with cottonseed, sesame, peanut, rape and poppy oils, it would not indicate the admixture of lard or olive oils or the entire sophistication by peach or apricot kernel oils. The Ger. Ph. introduces the following test "when 15 parts of the oil are thoroughly shaken with a mixture of 2 parts of water and 3 parts of fuming nitric acid, a whitish mixture free from red or brown color should be formed which should separate after several hours into a firm white mass and a nearly colorless liquid. This test will serve to indicate adulterations with peach kernel, apricot kernel, sesame, and peanut oil if present in considerable quantity. The reaction with an equal volume of hydrochloric acid and a fragment of sugar is a very delicate test for sesame oil, the acid liquid separating of a bright red color gradually assuming a purplish tint. While testing these oils with this test it was observed by the writer that on agitating several of the samples with an equal volume of pure hydrochloric acid (sp. gr. 1.2) the oil became white and the acid separated assuming in a few minutes a bright emerald green color. Thinking that this might possibly be due to some metallic impurities in the oil the acid liquid was separated and tested for metals with a negative result. A number of pure oils were examined to determine the cause of the reaction, but none of them would give similar results. Various mixtures of pure oils were tried and from these the conclusion was derived that the reaction noted was due to a mixture of arachis and sesame oils. Pure arachis oil gives no reaction with hydrochloric acid, while sesame oil gradually assumes a reddish color and the acid becoming also of a faint reddish tint. That a mixture of these oils should produce this reaction has I believe not before been observed. Oxygen seems to be necessary to the reaction and it is noticeable that with rancid oils the reaction is more distinct. The following table exhibits the color reactions of the oils and also the iodine absorptions. Jour. Pharm , 1889 Yellow, outer edge becoming Yellow mixture. In 24 hours oil in two Oil. U.S. P. Test. 2 drops H2504 on Ger. Ph. Test. 15 parts of Oil, 2 parts H2O, 8 drops of oil. 3 parts HNO3 fuming. 1 vol. HNO, (1.42.) HCl +sugar] HCI 1.20. * Iodine Absorption. N.o. 1. White mixture. In 24 hours oil almost White, acid colorless No change. No change. solid white mass, acid liquid colorless. 96.646 Greenish turning to Red. yellow, acid orange Green. 106.260 3. 6. dish brown, on stirring dirty Dark brown with black spots, Bright orange, on stirring Brownish yellow, becoming Dark red-brown, on stirring an Yellow, outer edge greenish, Yellow, becoming darker, on Yellow, on stirring gray. Yellow, stirring almost colorless. Bitter almond, yellow, tinged with green on outer edge, on Peach blossom red. In 24 hours oil partly Peach blossom red. In 24 hours oil almost Peach red, acid col- No change. No change. orless. Peach red,acid color- No change. less. Yellow, acid yellow. Red. Orange mixture. In 24 hours oil yellow, Greenish, changing Red. Peach blossom red. In 24 hours oil solid- White mixture. In 24 hours almost solid, White, acid colorless No change. No change. acid liquid colorless. White, acid colorless No change. *I am indebted to my friend, Mr. Wm. Beam, for his assistance in taking the iodine equivalents of these oils. |