Cyclopropenoid Fatty Acids in Malagasy baobab: Adansonia grandidieri (Bombacaceae) Seed Oil

Adansonia grandidieri (bombacaceae family) seed oil gives a positive Halphen test. Composition analysis of derivatized fatty acid methyl esters, in presence of silver nitrate in anhydrous methanol, after chromatography fractionation on silicagel column, were made by gas-liquid chromatography (GLC) using a packed DEGS column. Presence of malvalic and sterculic acids were detected. GLC analysis using glass capillary columns coated with Carbowax 20 M and BDS shows that A. grandidieri seed oil contains mainly palmitic (41%), oleic (22%) and linoleic (12%) acids. Cyclopropenic fatty acid concentration was 14% with 6% for malvalic and 8% for sterculic acids. A slight proportion of dihydrosterculic acid (1.5%) was observed. GLC fatty acid methyl esters analysis, without derivatization, on the two glass capillary columns coated with Carbowax 20 M and BDS gave the same results for cyclopropenic acids content.     

GLC and TLC analysis of isopropylidene derivatives of isomeric polyhydroxy acids derived from positional and geometrical isomers of unsaturated fatty acids

Gas-liquid chromatography (GLC) and thin-layer chromatography (TLC) were used to investigate the isomeric positional geometrical isopropylidene derivatives of nine isomeric dihydroxy esters, four isomeric methyl 9,10-12-trihydroxystearates, and eight isomeric methyl 9,10-12,13-tetrahydroxystearates prepared from unsaturated fatty acids. The isopropylidenes derived fromcis andtrans monounsaturated fatty acids were easily separated on both polar and nonpolar columns. Positional isopropylidenes derived from positional isomers of monounsaturated fatty acids were not separated on either liquid phase but were resolved by TLC. Four of the eight isomeric isopropylidenes derived from the four geometrical isomers of linoleic acid were resolved on the polar column; the other four isomers eluted as a single peak. The four isomeric isopropylidene-trifluoroacetate derivatives derived from ricinoleic and ricinelaidic acids were also resolved on the polar column. GLC analyses were carried out with liquid phases of ethylene glycol succinate methyl silicone polymer (EGSS-X) and methyl silicone polymer (SE-30) packed columns. Isopropylidenes, in addition to their applicability for the resolution of polyhydroxy acid mixtures, are particularly useful for the determination of double bond positions and geometrical configurations of fatty acids without cleavage. Under contract with the U. S. Atomic Energy Commission.     

Fatty acid composition of seed oils from sixAdansonia species with particular reference to cyclopropane and cyclopropene acids

The oil content of sixAdansonia species (Bombacaceae family) of Madagascar (Adansonia grandidieri, A. za, A. digitata, A. fony, A. madagascariensis andA. suarenzensis) and Africa (A. digitata) ranges from 8 to 46%. All the oils give a positive response to the Halphen test. Malvalic, sterculic and dihydrosterculic acids were detected using gas liquid chromatography-mass spectrometry (GLC-MS). Epoxy or hydroxy fatty acids were not found in these oils. Fatty acid composition was determined by GLC using glass capillary columns coated with BDS and Carbowax 20 M. Results obtained for cyclopropenic fatty acids (CPEFA) were compared to those given by glass capillary GLC after derivatization with silver nitrate in methanol, by hydrogen bromide titration and by proton magnetic resonance (PMR). Good agreement was observed for the results given by the various methods. Malvalic acid content ranges from 3 to 28%, sterculic acid from 1 to 8% and dihydrosterculic acid from 1.5 to 5.1%. Odd-numbered fatty acids (Pentadecanoic and hepatadecanoic) were also observed in minute amounts (0.1–1.1%). Among the normal fatty acids, we observed mainly palmitic (21–46%), oleic (15–40%) and linoleic (12–32%). The relationship between fatty acid composition andAdansonia species is discussed.     

An analysis of separation factors applicable in the gas-liquid chromatography of unsaturated fatty acid methyl esters on a polyester substrate

The employment of gas-liquid chromatography (GLC) separation factors between methyl esters of unsaturated fatty acids is feasible as a means of tentative identification, either between acids of one chain length and differing numbers of double bonds, or between acids of one chain length and the same number of double bonds in differing positions, provided the acid structures are appropriately grouped by end carbon chain. The modification of separation factors by temperature, chain length, number of double bonds, or position of double bonds is apparent from examination of a larger number of examples than was hitherto available. Examples of the usefulness of separation factors in identifying unknowns or predicting retention times are given.     

Dihydrosterculic acid,a major fatty acid component ofEuphoria longana seed oil

The seed oil ofEuphoria longana, Sapindaceae, contains 17.4% of 9,10-methyleneoctadecanoic (dihydrosterculic) acid. This identification is based on information from thin layer chromatography, infrared analysis, gas liquid chromatography, nuclear magnetic resonance and mass spectroscopy. Since GLC of the oil showed components that emerged between the usual triglycerides, the cyclopropanoid acid is apparently a triglyceride constituent. The presence of smaller amounts, less than 1%, of cyclopropanoid fatty acids of different chain lengths is indicated by GLC and TLC analyses of the methyl esters. The other major fatty acids in this oil are: 16∶0 (19%), 18∶0 (7%), 18∶1 (36%), 18∶2 (6%), 18∶3 (5%) and 20∶0 (4%).Euphoria oil contains considerably larger amounts of cyclopropanoid fatty acids than previously reported in other seed oils. Presented at the AOCS-AACC Joint Meeting, Washington, D.C., April 1968. No. Utiliz. Res. Dev. Div.; ARS, USDA.     

Production of fatty alcohols from fatty acids

Detergent-range alcohols from natural feedstock can be produced by high pressure hydrogenation of either methyl esters or fatty acids. The increasing quantities of fats and oils on the world market secure a reliable and economically priced material. Although fatty acid is an abundant worldwide commodity, most alcohol producers hydrogenate methyl esters, because direct hydrogenation of fatty acids is difficult as the catalyst is sensitive to acid attack. The process described here makes it possible to hydrogenate fatty acids directly to alcohols of high quality without prior esterification. The reaction takes place in the liquid phase over a fine-grained copper chromite slurry in a single reactor vessel. A special reactor design with an optimum arragement of the feeding nozzles causing an appropriate circulation of the reacting components inside the reactor facilitates the rapid “in situ” esterification reaction. This minimizes the free fatty acid concentration in the reactor to nearly zero. This results in a low consumption of catalyst. The most important advantages of the process are: direct feed of fatty acids of various origins, use of reasonably priced raw materials such as soapstock fatty acids and lower grade tallow acids, no process steps with methanol, and excellent economics. The process is industrially proven.     

An automated gas-liquid chromatographic method of measuring free fatty acids in canola

An automated method for measuring free fatty acids (FFA) in canola seed was developed by using gas-liquid chromatography (GLC). The results from the GLC method were linearly related (r²=+0.98) to those obtained with the traditional method involving Soxhlet extraction followed by a titration. In a nested experiment of over 11 different seedlots, the extraction and injection errors were 0.11 and 0.018%, respectively, of the total variation. The variation attributed to sampling within a seedlot was twice the variation attributed to extraction and injection errors combined. A seed sample size of at least 10 mL was needed to prevent the standard deviation from increasing as the FFA mean increased. The GLC method was precise and rapid, and also identified which fatty acids were being cleaved from the oil, but a linear adjustment improved accuracy.     

Co-occurrence of Coronaric and Vernolic Acids in Compositae Seed Oils

Seed oils of Lactuca scariola Linn., L. sativa Linn. and Siegesbeckia orientalis Linn., were found to contain epoxy acids in 10.0% (6.0% coronaric + 4.0% vernolic), 27.4% (16.9% coronaric + 10.5% vernolic) and 20.0% (16% coronaric + 4.0% vernolic) amount, respectively, alongwith normal fatty acids. The co-occurrence of the two epoxy acids was confirmed by chromatographic (TLC, GLC), spectroscopic and chemical methods. Further, this was confirmed by mass spectral study of methyl ester and its methoxy hydroxy derivative in the case of S. orientalis seed oil.The seed oils of Chrysanthemum coronariumand Vernonia anthelmintica were used as reference standard.     

Application of methoxy-bromomercuri-adduct fractionation to the analysis of fatty acids of partially hydrogenated marine oils

The fatty acids of a refined and of a partially hydrogenated menhaden oil, iodine value (IV) 84.5, were separated into different classes (e.g., monoene, diene, including pentaene and hexaene) by thin layer chromatography (TLC) of their methoxy-bromomercuri-adducts (MBM). In the solvent system hexane: dioxane, the separation of fatty acids occurred according to the degree of unsaturation. No influence was exerted by either the geometry or the position of the ethylenic bonds. The effect of the various chain lengths (C₁₄−C₂₂) was to broaden the bands, but no overlap occurred among the chain lengths. A wide range of C₂₀ unsaturated fatty acids were prepared by the hydrazine reduction of 20∶5-Δ5,8,11,14,17. These were separated into groups as MBM adducts and identified by comparison of their experimental and calculated equivalent chain lengths (ECL) in gas liquid chromatography (GLC) on SILAR-5CP and SILAR-7CP columns. This confirmed that GLC did not totally separate all groups of isomers of different degrees of unsaturation. The quantitative analysis of both refined and partially hydrogenated (IV-84.5) menhaden oils by GLC was effected by the recovery of the fatty acid methyl esters from the MBM adduct TLC bands with the addition of methyl heptadecanoate (17∶0) as an internal standard, followed by analysis of the different fractions on open-tubular columns coated with SILAR-5CP. For methylene- and nonmethylene-interrupted unsaturated acids, 100% recovery from the MBM adducts was achieved, but in the case of the conjugated dienes the maximal recovery was 70%.     

Composition of the fat extracted from the seeds of theobroma bicolor

The fat fromTheobroma bicolor was analyzed for glyceride content by thin layer chromatography (TLC), and for fatty acid composition and triglyceride (carbon number) composition by gas liquid chromatography (GLC). The fat was then separated into glycerides of different degrees of unsaturation by means of silver nitrate TLC. Then, the bands were examined by GLC before and after conversion to methyl esters. From the results obtained, the distribution of the fatty acids on the individual glycerides was calculated. The fat consisted of 96.5% triglyceride with only 2.5% diglyceride and 1.7% free fatty acid. The major fatty acids present were 42.3% C18:0, 45,2% C18:1, and 6.0% C16:1. Most of the triglycerides were of carbon number 52 (18.0%) and 54 (77.6%). The major triglycerides were 38.6% 1-stearyl-2,3 diolein (SOO), 25.4% 2-oleyl-1,3 distearin (SOS) and 13.8% 1-palmito-2-oleyl-stearin (POS). Only 44.3% of the fat consisted of monounsaturated triglycerides.     

Homogeneously catalyzed hydrogenation and gas-liquid chromatographic analysis of the methyl esters of cyclopropene fatty acids

Various concentrations of cyclopropene fatty acids have been determined down to 0.2% by the use of gas liquid chromatographic (GLC) analysis of the methyl esters of fatty acids that have been quantitatively hydrogenated using a homogeneous transition metal complex catalyst. The effectiveness of the use of bromotris(triphenylphosphine)-rhodium(I), Br(P(C₆H₅)₃)₃Rh, as a homogeneous hydrogenation catalyst to convert the cyclopropene ring to a cyclopropane ring has been evaluated and compared with the analogous chloro- and iodo-complexes. The hydrogenation/GLC method of analysis has been compared with the method of titration with hydrogen bromide in benzene and with the method involving the use of high resolution nuclear magnetic resonance (NMR).     

Determination of the glyceride structure of fats. glyceride structure of fats with unusual fatty acid compositions

Five fats containing less common fatty acids, nutmeg butter (myristic), rapeseed oil (erucic, eicosenoic), peanut oil (arachidic, behenic, lignoceric), tung oil (eleostearic), and coriander seed oil (petroselinic) were oxidized, and the oxidized esterified glycerides were analyzed by gas-liquid chromatography (GLC). The values obtained are compared with those calculated from lipase hydrolysis data. Although there was a general over-all agreement between the compositions calculated from lipase hydrolysis data and that obtained by GLC analysis of the oxidized glycerides, there were some discrepancies that exceeded the range of experimental error. 1 Issued as N.R.C. No. 9626.     

Cyclopropane fatty acid metabolism: Physical and chemical identification of propane ring metabolic products in the adipose tissue

Twelve male weanling rats were distributed equally into 3 groups and placed on fat-free diets. The diets of groups 1 and 2 were supplemented with 0.54% of recemic methylcis-9,10-methylene octadecanoate (CMO) and racemic methyltrans-9,10-methylene octadecanoate (TMO), respectively. Group 3 served as a control. Gas liquid chromatography (GLC) analyses of the adipose tissue methyl esters indicated at the level fed, that cyclopropane fatty acids do not affect normal fatty acid metabolism as has been shown for cyclopropene fatty acids. GLC analyses of groups 1 and 2 revealed the presence of a different unidentified fatty acid for each of the acids fed in addition to the CMO and TMO acids themselves. Each of the unidentified acids and the CMO and TMO acids were isolated and purified by preparative GLC. The absolute identity of the CMO and TMO acids fed and isolated from body fat was established by IR, NMR, and mass spectra. The biodegradation products of the CMO and TMO esters were shown to becis- andtrans-3,4-methylene dodecanoic acid, respectively. Unequivocal proof of structure was established through synthesis followed by comparison of IR, NMR, and mass spectra and melting points, GLC retention times, and elemental analyses with those obtained for the degradation products. Neither member of the racemic mixtures of either thecis or thetrans cyclopropane acids was preferentially utilized by the rat as shown by the lack of octical activity in the degradation products and the CMO and TMO acids isolated from the body fat. The accumulations of the 3,4-methylene dodecanoic acids in the adipose tissue of the rats fed CMO and TMO cyclopropane fatty acids suggest the inability of the beta oxidation enzyme system to proceed past the cyclopropane ring in a fatty acid chain. The synthesis ofcis- andtrans-3-dodecenoic acids, intermediates in the synthesis of the 3,4-methylene dodecanoic acids, and the geometrical cyclopropane isomers are discussed. This work to be submitted in partial fulfillment of the requirement for Ph.D.     

Jojoba oil wax esters and derived fatty acids and alcohols: Gas chromatographic analyses

HCl-catalyzed ethanolysis followed by saponification readily surmounts the resistance of long chain wax esters to direct hydrolysis by alkali. Additionally, choosing ethyl instead of methyl esters allows baseline separations between long-chain alcohols and corresponding esters in gas liquid chromatographic (GLC) analysis of total alcohol and acid components before saponification. Liquid wax esters were analyzed on a temperature-programmed 3% OV-1 silicone column. Geographical and genetic effects on the variability of jojoba oil composition were investigated with five different seed samples. Major constituents in jojoba seed oil from shrubs in the Arizona deserts, as indicated by GLC analyses of oil, ethanolysis product, isolated fatty alcohols and methyl esters of isolated fatty acids, were C₄₀ wax ester 30%, C₄₂ wax ester 50% and C₄₄ wax ester 10%; octadecenoic acid 6%; eicosenoic acid 35%, docosenoic acid 7%, eicosenol 22%, docosenol 21% and tetracosenol 4%. Oil from smaller leaved prostrate plants growing along California’s oceanside showed a slight tendency toward higher molecular size than oils from the California desert and Arizona specimens. The wax esters are made up of a dispro-portionately large amount of docosenyl eicosenoate and are not a random combination of constituent acids and alcohols.Lunaria annua synthetic wax ester oil was used as a model for evaluating the analytical procedures. Presented at the AOCS Meeting, Chicago, September 1970 No. Utiliz, Res. Dev. Div., ARS, USDA.     

A rapid and quantitative procedure for the preparation of methyl esters of butteroil and other fats

A simple and convenient method for the quantitative preparation of methyl esters of fatty acids from glyceride fats and oils is described. The procedure, using potassium methylate as catalyst and a heating interval of 2 min at 65C in a closed vial, is applicable to fats containing both low and high molecular weight fatty acids such as butteroil. The methyl esters of samples ranging from a few mg to 30 mg are isolated by CS₂ extraction and a TLC technique. A similar procedure using sulfuric acid in methanol as catalyst is described for the conversion of free fatty acids to methyl esters. For the routine analysis by GLC of fats and oils such as lard, tallow, soybean, cottonseed oil or butteroil, no isolation of the methyl ester is required. A CS₂ extraction carried out in the reaction vial allows the GLC analysis immediately after the reaction period (2 min). Presented at the AOCS Meeting, Philadelphia, October 1966. E. Utiliz. Ees. Dev. Div., ABS, USDA.     

Analysis of fats and oils by gas-liquid chromatography and by ultraviolet spectrophotometry

1. Known mixtures of pure fatty acid methyl esters and a number of fats and oils as their methyl esters have been analyzed by conventional GLC with thermal conductivity detectors.
2. Percentage of fatty acid distribution determined by GLC agreed well with known percentages in model mixtures and with analysis by the spectrophotometric method for fats and oils.
3. Determination of very small amounts of arachidonic and pentacnoic acids in lard by GLC was not successful.

     

Separation of fatty acid methyl esters on the basis of the number of double bonds using alumina plates

The separation of fatty acid methyl esters (FAME) on the basis of the number of double bonds present in the molecule was accom-plished using thin layer chromatography (TLC) on alumina. Hexane was used as the solvent in a continuous development mode using modified tanks. The separations were verified by gas liquid chroma-tography (GLC) and retention of structural integrity was confirmed by infrared analysis fortrans isomerization and by ozonolysis-GLC for double bond position. Presented at the 72nd AOCS annual meeting, New Orleans, 1981.     

A rapid low temperature method for preparation of methyl esters of fatty acids

A rapid method for preparation of methyl esters of fatty acids in lipids has been accomplished by forming the sulfuric acid complex of the lipid in ethyl ether at the temp of a dry ice-acetone bath. Decomposition of the complex with methanol results in direct formation of methyl esters of the fatty acids. A comparison was made of gas liquid chromatography (GLC) analysis of fatty acid composition of several fats using methyl esters prepared by this and by two other methods. Results of this comparison reveal that the method is not only rapid but provides complete reaction with no apparent changes in the fatty acids. Mich. Agr. Exp. Sta. Pub. No. 3503. Presented at the AOCS meeting in Chicago, 1964.     

Identification and characterization of fully deuterated fatty acids isolated fromScenedesmus obliquus cultured in deuterium oxide

The algaScenedesmus obliquus cultured in deuterated water, synthesized fully deuterated saturated and unsaturated long chain fatty acids. Their methyl esters were purified and their equivalent chain lengths were determined by gas liquid chromatography (GLC). They were characterized by mass spectroscopy, IR and near-IR spectroscopy, and NMR spectroscopy. Hexadeca-3,6-dienoic acid was identified. The fatty acid compositions of the total lipid and of individual lipid classes were measured. The melting point of methyl perdeuteriohexadecanoate was lower than that of its hydrogen counterpart. Methyl esters of perdeuterio fatty acids had shorter retention times in GLC chromatography on polar and nonpolar phases. Presented before ISF-AOCS Congress, Chicago, September 1970.     

Curupira tefeensis (Olacaceae) — A Rich Source of Very Long Chain Fatty Acids

The fatty acid composition of the seed oil of Curupira tefeensis was analysed by capillary GC of their methyl esters. The gaschromatographic assignments were ensured by corresponding mass spectra. The oil is composed to more than 62% of very long chain fatty acids (>C18). Erucic acid is found to be the main component (35%). The position of the double bonds of the monounsaturated fatty acids (MUFAME) was verified after derivatization with dimethyl disulfide and subsequent GC/MS analysis. All identified MUFAME belong to the (n-9-)type. The UV-spectroscopical data show that approx. 1.2% conjugated acetylenic fatty acids occur in the oil. Furthermore IR- and NMR-spectroscopical investigations and the basic analyses of the seed were carried out.