Polymorphism of mixed triglycerides containing odd fatty acids

Paris of C _n C_(n+1)C _n (i.e., C₁₆C₁₇C₁₆ and C₁₈C₁₉C₁₈) and C _n C_(n-1)C _n triglycerides (C ₁₆ C ₁₅ C ₁₆ and C ₁₈ C ₁₇ C ₁₈ ) triglycerides,n even, were prepared to compare with C _n C_(n+2)C _n and C _n C_(n-2)C _n glycerides, respectively, in polymorphic behavior. It was found that C _n C_(n+1)C _n compounds were β′ tending and C _n C_(n-1)C _n compounds β tending in line with their all-even counterparts. The glyceride C₁₁C₁₃C₁₁ is β′ stable, like C₁₀C₁₂C₁₀ and C₁₆C₁₈C₁₆, and seems closely related to them in physical behavior and diffraction characteristics.     

High performance size exclusion chromatography of fatty acids,mono-, di- and triglyceride mixtures

A high performance size exclusion chromatographic (HPSEC) method is described for the separation and quantitation of fatty acids, mono-, di- and triglyceride mixtures. The various lipid components were separated on two columns packed with 5 μm styrene/divinylbenzene copolymer and connected in series. Toluene was employed as eluant, and components were monitored by refractometry. A formula derived for calculation of total weighted correction factors (WCF) for the various lipid classes based on known values of correction factors of simple lipid components and the fatty acid composition of the sample allowed quantitation of lipid mixtures containing a variety of different molecules. The precision of the experiments is such that the relative standard deviation for each lipid component was 1–5%, and a component could be detected at 0.05% level.     

Gas-liquid chromatography of fatty derivatives. II. Analysis of fatty alcohol mixtures by gas-liquid chromatography

Conclusions Gas-liquid chromatography has been shown to be applicable to the analysis of fatty alcohols. Through the use of polyester columns these alcohols have been separated according to chain length and degree of unsaturation. A study has been made of the relationship between peak areas of the chromatograms and the actual weight percentages of the four C₁₈ alcohols found in the fatty alcohols derived from linseed oil. Fatty alcohols, prepared from soybean, linseed, and sperm oil have been prepared and analyzed by the proposed procedure. Craig and Murty (1) have recently reported that polyesters based on succinic acid are preferable for the liquid phase of the chromatographic column to those made from adipic in that they afford a better separation of methyl stearate from methyl oleate. Conversely adipic columns gave a more effective separation of the esters of linolenic and arachidic acids. The application of these polyesters to the analysis of fatty alcohol acetates is expected to improve their separation in a similar fashion, but further work is indicated in the search for a liquid phase that will permit both separations in the minimum time. ADM Technical Talk No. 166.     

Gas-liquid chromatography of fatty derivatives

Summary The separation of fatty amines has been carried out with nonpolar substrates on solid supports of Chromosorb and Chromosorb W, which were previously treated with potassium hydroxide to overcome adsorptivity. In this manner well-resolved symmetrical peaks are obtained. Untreated supports give peaks which trail and prohibit precise quantitative measurements. Both Apiezon L on Chromosorb W and Silicone Grease on Chromosorb have proved effective, the latter at 176°C. and the former at 225°C. Relative detector sensitivity factors have been determined for the amines C₈ to C₁₈, thus permitting accurate analyses. The relative response for primary alkyl fatty amines is a linear function of molecular weight. The application of gas chromatography described in this paper was conceived and developed independently and simultaneously in the respective research laboratories of these two companies.     

Gas-liquid chromatography of bile acids

Methods are reviewed for the preparation, gasliquid chromatographic (GLC) separation, identification, and quantitative estimation of the trifluoroacetyl derivatives of bile acid methyl esters. Of the stationary phases tried (SE-30, QF-1 and XE-60) methylfluoroalkyl silicone (QF-1) was best suited for analysis of the trifluoroacetates. This phase (1–2% QF-1 on 100–120 mesh Gas Chrom P) allowed an orderly resolution of conformational isomers and consistently gave GLC columns (stainless steel tubes, 1/8 in. O.D. × 3 ft) from which the bile acid derivatives could be recovered in high yield. Applications to biological materials are illustrated with bile acid samples from animal biles and from human duodenal drainage and feces. Identifications of the major bile acids made by the GLC of the trifluoroacetates were confirmed by results obtained with bile acid methyl esters and bile acid methyl ester acetates on QF-1 and the other liquid phases investigated. For most mixtures of bile acids, however, it appears that GLC of methyl esters and methyl ester trifluoroacetates on QF-1 is sufficient for a reliable recognition of common bile acids. Overall accuracy of the estimates was of the order of ± 5%, but it varied with the nature and concn of the component.     

Thia fatty acids with the sulfur atom in even or odd positions have opposite effects on fatty acid catabolism

As tools for mechanistic studies on lipid metabolism, with the long-term goal of developing a drug for the treatment of lipid disorders, thia FA with the sulfur atom inserted at positions 3–9 from the carboxyl group were fed to male Wistar rats for 1 wk to determine their impact on key parameters in lipid metabolism and hepatic levels of thia FA metabolites. Thia FA with the sulfur atom in even positions decreased hepatic and cardiac mitochondrial β-oxidation and profoundly increased hepatic and cardiac TAG levels. The plasma TAG level was unchanged and the hepatic acyl-CoA oxidase activity increased. In contrast, thia FA with the sulfur atom in odd positions, especially 3-thia FA, tended to increase hepatic and cardiac FA oxidation and acyl-CoA oxidase and carnitine palmitoyltransferase-II activities, and decreased the plasma TAG levels. The effects seem to be related to differences in the catabolic rate of the thia FA. Differences between the two groups of acids were also observed with respect to the regulation of genes involved in FA transport and catabolism. Feeding experiments with 3- and 4-thia FA in combination indicated that the 4-thia FA partly attenuated the effects of the 3-thia FA on mitochondrial FA oxidation and the hepatic TAG level. In summary, the position of the sulfur atom in the alkyl chain, especially whether it is placed in the even or odd position, is crucial for the biological effect of the thia FA. The first and second authors contributed equally to the work.     

Gas-liquid chromatographic analysis of cyclopropenoid fatty acids

A method is described for the analysis of cyclopropenoid fatty acids in oils. The method consists of reacting the methyl esters of the cyclopropenoid fatty acids with silver nitrate in methanol to form ether and ketone derivatives. The derivatives formed from the cyclopropenoid fatty acids are separated from the methyl esters of the normal fatty acids by gas-liquid chromatography on a 15% diethylene glycol succinate column. The method is applicable to oils containing from 0.01% to 100% of cyclopropenoid fatty acids. The derivatives of oils containing lew levels of cyclopropenoids are separated from the normal methyl esters by alumina chromatography prior to gas-liquid chromatography. Studies on the quantitative aspects of the derivative formation, alumina chromatography, and gas-liquid chromatography are reported. Analyses for total cyclopropenoid fatty acid content of cottonseed oil andSterculia foetida oil by the gas-liquid chromatographic and hydrobromic acid titration procedures showed good agreement. Replicate analyses of a sample ofSterculia foetida oil for malvalic and sterculic acid gave coefficients of variation of 6.04% and 1.17%, respectively.     

Gas-liquid chromatography of polar fatty derivatives1.2

The direct separation of fatty amides is achieved using a polyamide. Versamid 900, as the partitioning agent on a support which need not be previously impregnated with strong alkali or acid, procedures usually followed in the GLC separation of highly polar materials. The combination of a neutral support and polar substrate permits the separation of unsubstituted and substituted long chain fatty amides with as many as 24 carbon atoms with good resolution, in a reasonable time, and with good peak symmetry. The observed area responses agree with the wt percentages of standard amide mixtures, indicating that no loss of amides occurs on the column under the conditions employed. The Versamid column has proved useful in the analysis of other polar fatty derivatives. Conjugated dienoic and trienoic acids run as their methyl esters are retarded sufficiently on Versamid 900 so that they may be estimated in the presence of other fatty acids. Mixtures of compounds with varying polarity, such as mono-, diand triacetin, and glycerol, may be separated easily. Hydroxy and normal fatty acid methyl esters give equally summetrical peaks. Presented at the AOCS meeting, Minneapolis, 1963 Technical Paper, No. 259, ADM Co.     

Gas-liquid chromatographic analysis of cyclopropene fatty acids

A gas-liquid chromatographic method is described for the quantitative estimation of cyclopropene fatty acids as their methyl mercaptan derivatives. This method estimates individual cyclopropene acids as well as normal and cyclopropane acids. Nine seed oils were analyzed for their cyclopropene fatty acid content. Evidence was obtained for the presence of a cyclopropene fatty acid of shorter chain length than malvalic inAlthaea rosea cav and one with a higher chain length than sterculic inBombacopsis glabra seed oil. This method is less accurate for cottonseed oil than for the other oils tested because of the appearance of some unsymmetrical peaks of unknown origin. The mercaptan derivatives of the cyclopropene acids may be isolated by silver ion thin-layer chromatography. Small amounts of cyclopropane fatty acids were found in a number of the oils analyzed for cyclopropene fatty acids. Presented at the AOCS meeting, Chicago, October 1964.     

Fractionation of triglyceride mixtures by preparative gas chromatography

A semiautomatic system is described for gas-chromatographic separation and recovery of triglycerides of uniform molecular weight in milligram quantities. It employs an Aerograph Autoprep 700 (Wilkens Instrument and Research Inc.) equipped with a stream splitter and a hydrogen flame ionization detector. The column is an aluminum or stainless steel tube (1/4 in. O.D.×2 ft) and contains silanized Chromosorb W (60–80 mesh) coated with 5% (w/w) JXR or SE-30. Five to ten milligrams of mixed triglyceride are injected at a time and the temperature is programmed exponentially from 150 to 350C. With split ratios of 1∶5 to 1∶10 collections of 20 to 50 mg of each peak can be made with some 10 to 20 injections. Presented in part before the Canadian Committee on Fats and Oils, Ottawa, Ontario, Canada, October 1964.     

Gas-liquid chromatography of lipids,carbohydrates and amino acids

Gas-liquid chromatography is primarily a powerful separating tool. Compounds can be trapped as they emerge from the GLC apparatus for analysis by mass spectrometry and infrared or ultraviolet spectrophotometry, or the emerging separated components may flow directly into one of these instruments making positive identification of the components possible. Quantitative analyses of fats and oils are possible when certain requirements are observed. A combination of fatty acid, triglyceride and sterol analyses offers promise of a rapid means for the identification of fats and oils and their admixture or adulteration. Progress has been made on the preparation of derivatives of carbohydrates and amino acids such that these compounds may soon be analyzed as readily by GLC as lipids are today. Presented at the AOCS-AACC Joint Meeting, Washington, D.C., April 1968. E. Utiliz. Res. Dev. Div., ARS, USDA.     

High performance reversed-phase chromatography of natural triglyceride mixtures

High performance reversed-phase chromatography (HPRC) is an efficient and powerful tool gaining momentum in the separation of triglycerides and other lipid components. In the present study the effect of different variables in triglyceride separation has been studied. It was found that a longer hydrocarbon chain bonded to silica gel as well as the percent coverage improved the separation. Smaller particle size packing increased triglyceride resolution. A decrease in mobile phase polarity by increasing the acetone content resulted in a decrease in the retention time and resolution of triglyceride.     

Production of odd chain polyunsaturated fatty acids byMortierella fungi

A soil isolate,Mortierella alpina 1S-4, was found to show high production of odd chain polyunsaturated fatty acids (PUFAs) among various arachidonic acid-producingMortierella strains tested. The fungus mainly accumulated 5,8,11,M-cis-nonadecatetraenoic acid. With 5%n-hepta-decane and 1% yeast extract as growth substrates, the amount of C_19:4:4 acid accumulated reached 44.4 mg/g dry mycelia (0.68 mg/mL of culture broth). This value accounted for 11.2% of the total fatty acids in the extracted lipids from mycelia, and odd chain fatty acids comprised over 95% of the total mycelial fatty acids. The addition of sesamin, a specific inhibitor of A5 desaturation, caused an increase in C_19:3 acid and an accompanying decrease in C_19:4 acid. On the other hand, species ofMortierella that could not produce C-20 PUFAs accumulated C-17 acids, but no C-19 PUFAs, when grown with fatty substrates with an odd chain skeleton. The odd chain PUFAs were distributed in both neutral and polar lipids. The biosynthetic route to C_19:4 acid was presumed to mimic the n-6 route to arachidonic acid as follows: C_17:0 → C_17:1→ C_17:2→ C_17:3 → C_19:3 → C_19:4 acids. On leave from Suntory Ltd.     

Determination of rosin acids in mixtures with fatty acids

Summary The authors describe an improvement in their analytical method for determination of the rosin-acids content in mixtures with fatty acids, especially for tall oil products. Good agreement is obtained for the whole range of rosin acids and fatty acids compositions. The method is faster, simpler, and less laborious than other methods that have been suggested, but seems to given as good results as these. The method can therefore advantageously be applied both for research work, sales analysis and as a routine control analysis.     

Foam performance of fatty acid soaps of odd carbon numbers

The foam capacities, foam stabilities, expanding single bubble stabilities, surfact tensions, and surface viscosities of the straight chain C₉–C₁₄ sodium soaps were measured at various concentration. The C₁₂–C₁₄ soaps, most notably the C₁₃, gave the best over-all foam performance of the compounds studied. The critical micelle concentrations for these soaps were also determined.     

Chromatographic studies on fatty acid dinners: Gas-liquid chromatography,high performance liquid chromatography and thin-layer chromatography

A high performance size exclusion Chromatographic method was developed for the separation of monomer, dimer and trimer fatty acids in thermally oxidized or used fats and oils. The system was composed of two styrene/divinylbenzene copolymer columns with toluene as the mobile phase and refractometry as the mode of detection. The internal standardization method was used for quantitation with monostearin as the internal standard. Quantitation of monomer, dimer and trimer content in various samples correlated well with results obtained by GLC analysis and gravimetically by size exclusion chromatography.     

Localization of a source of marine odd chain-length fatty acids. II. Seasonal propagation of odd chain-length monoethylenic fatty acids in a marine food chain

The unusual occurrence of elevated levels of odd chain length fatty acids (OCFA) in smelt taken during winter months in Jeddore Harbour, Nova Scotia, is due to the dietary intake of large numbers of the amphipodPontoporeia femorata (Kröyer). Sampling over two winters confirms that the seasonal peak period for this amphipod, in stomachs is mid-December to the end of February. The distributions of monoethylenic isomers are compared to distinguish exogenous and endogenous smelt dietary features in terms of the geographically limited phenomenon of high OCFA levels and the essential absence of biological activity for these acids.     

Gas-liquid chromatography of hydroxy fatty esters: Comparison of trifluoroacetyl and trimethylsilyl derivatives

Transformations of hydroxy to keto fatty esters have been monitored successfully by converting the hydroxy compounds to their trifluoroacetyl (TFA) or trimethylsilyl (TMS) derivatives followed by gas-liquid chromatography (GLC). The TFA derivatives have shorter retention times, are better separated from the keto esters, and permit more complete resolution of saturated and unsaturated hydroxy fatty esters than the TMS derivatives. Improved methods for derivative preparation which are rapid and convenient are described. Methyl dimorphecolate (methyl 9-hydroxy-trans,trans,10,12-octadecadienoate), which is thermally unstable and cannot be chromatographed as the trifluoroacetate or free hydroxy compound, was chromatographed satisfactorily as the trimethylsilyl ether. Presented at the AOCS Meeting in Philadelphia, October 1966. W. Utiliz. Res. Dev. Div., ARS, USDA.