Separation and quantitation of free fatty acids and fatty acid methyl esters by reverse phase high pressure liquid chromatography (original) (raw)
Related papers
Validation of a new procedure to determine plasma fatty acid concentration and isotopic enrichment
Assessment of free fatty acid (FFA) concentration and isotopic enrichment is useful for studies of FFA kinetics in vivo. A new procedure to recover the major FFA from plasma for concentration and isotopic enrichment measurements is described and validated. The procedure involves extraction of plasma lipids with hexane, methylation with iodomethane (CH 3 I) to form fatty acid methyl esters (FAME), and subsequent purification of FAME by solid phase extraction (SPE) chromatography. The new method was compared with a traditional method using thin-layer chromatography (TLC) to recover plasma FFA, with subsequent methylation by BF 3 /methanol. The TLC method was found to be less reliable than the new CH 3 I method because of contamination with extraneous fatty acids, chemical fractionation of FFA species, and incomplete recovery of FFA associated with TLC. In contrast, the CH 3 I/SPE method was free of contamination, did not exhibit chemical fractionation, and had higher recovery. The iodomethane reaction was specific for free fatty acids; no FAME were formed when esterified fatty acids (triglycerides, cholesteryl esters, phospholipids) were subjected to the methylation reaction. We conclude that the CH 3 I/SPE method provides rapid and convenient recovery of plasma fatty acids for quantification or GC/MS analysis as methyl esters, and is not subject to the problems of contamination, reduced recovery, and chemical fractionation associated with recovery of FFA by Validation of a new procedure to determine plasma fatty acid concentration and isotopic enrichment. J. Lipid Res. 1999. 40: 2118-2124.
Journal of Chromatography B: Biomedical Sciences and Applications, 1985
The accumulation of free fatty acids (FFA) and the degradation of phospholipids are among the characteristics found in injured and edematous brains [l-51. In order to study the mechanisms involved, a high-performance liquid chromatographic (HPLC) method which can separate and monitor FFA and various phospholipids simultaneously would be very useful. Although there are a number of studies describing the separation of phospholipid classes by HPLC [ 6--121, a suitable method cannot be found that would also allow one to monitor FFA simultaneously.
Progress in the Analysis of Lipids XIII: Gas Chromatography, Part 5
Fette, Seifen, Anstrichmittel, 1973
esterung eingetreten ist (Tab. 3). Palmitin-, Linol-und die Summe von Linolen-und Eicosensaure sind in gleicher Menge vorhanden. Obwohl fur Stearin-, Ul-und Erucasaure die Unterschiede in den Positionen kleiner geworden sind, kann aus den Ergebnissen der Lipasehydrolyse nicht gesagt werden, dai3 wahrend der Umesterung alle Fettsauren statistisch neu verteilt wurden. Zwischen Ausgangstriglyceriden und restlichen Triglyceriden bestehen fur Ulsaure, Linolsaure und Erucasaure Unterschiede von 5 bis 6 % absolut, die die Substratspezifitat der Pankreaslipase zeigen. Tabelle 4 Fettsiiuren-Zusammensetrung (Gew.-Vo) der Triglyceride und durdi Umsatr mit Methylmagnesiumbromid gebildeter Spaltlrodukte einer Margarinefett-Misdtung nach der Umesterung Fettsaure (C-Zahl u. Doppelbindungen) ClS
Journal of Chromatography A, 1982
By combined application of chemicalpretreatments, and chromatographic and spectroscopic methods, it is possible to coordinate individual species of a complex lipid extract with high safety. In the sample studied, besides a high content of pal&tic and cis-vaccenic acid, smalI amounts of unusual fatty acids containing hydroxy groups and cyclopropane rings weredetected. The presence of polyunsaturated fatty acids was excluded by structure-retention relationships, which were obtained on phases of different polarity_ On the basis of these studies, and without the use of reference substances, a routine analysis of these unusual fatty acids in biological materials is possible_
Effect of column and software on gas chromatographic determination of fatty acids
Journal of Chromatography B, 2002
Four capillary columns (A: CP-WAX 52 CB 25 m30.25 mm; B: CP WAX 52 CB 30 m30.25 mm; C: CP-WAX 58 CB 25 m30.25 mm, Chrompack; D: OMEGAWAXE 320 30 m30.32 mm, Supelco) and two integration software (Mosaic ® v.5.10, Chrompack and CSW v.1.7, Data Apex ) were compared for analysis of fatty acids. Column A was mounted stepwise in two different instruments. Fatty acids of blood plasma phosphatidylcholine and standard mixture of saturated fatty acids were analysed as methyl esters under identical chromatographic conditions. Both integrating software did not differ significantly in most results; differences were observed only for minor components: 16:1n9 (0.1060.020 vs. 0.1760.005 M%, P,0.0001, column A1; 0.0960.011 vs. 0.1660.007 M%, P,0.0001, column A2; 0.0960.010 vs. 0.1760.003 M%, P,0.0001, column C; 0.0960.008 vs. 0.1960.003 M%, P,0.0001, column D), 20:0 (0.1060.001 vs. 0.0660.005 M%, P,0.05, column C) and 20:2n6 (0.4360.030 vs. 0.9160.016 M%, P,0.0001, column A2). Increased values for 16:1n9 and 20:2n6 integrated by MOSAIC are caused by cointegration of two poorly resolved peaks: fatty acid and impurity from sample matrix. Lower values for 20:0 are caused by incomplete integration of minor peak. Differences between columns were observed mostly for minor fatty acids. The results indicate that CSW is more suitable software for integration of complicated chromatograms. Linear calibration dependences measured with standard mixture of saturated fatty acids (carbon number 10-24) were observed in wide range of concentrations (three orders). Slope close to unity and minimal value of intercept confirmed theoretical relations when analyses are run under optimal conditions. Use of one column is advisable in small intervention or experimental metabolic studies. (M. Vecka). splitless injection technique and flame ionisation 1570-0232 / 02 / $ -see front matter
Quantitative gas liquid chromatographic analysis of butterfat triglycerides
Journal of the American Oil Chemists’ Society, 1963
A comparison has been made of the milk and adipose tissue triglycerides of rabbits and guinea pigs provided with one diet and of rats and mice provided with another. Both intact triglycerides and component fatty acids were analyzed by gas-liquid chromatography. Good correlation of the data obtained by the two techniques was obtained by calculating the average chain length of the fatty acid moieties. Little difference was found in the triglyceride composition of the adipose tissue of the different species. However, wide variation in the triglyceride composition of the milk was found between the species: the average fatty acid chain length in milk was 11.7 for rabbits, 14.2 for rats, 15.3 for mice, and 17.2 for guinea pigs. The corresponding values for adipose tissue were in the range 16.9-17.4 in all animals. The significance of enzymes that synthesize short-chain fatty acids in mammary gland is discussed. KEY WORDS gas-liquid chromatography triglycerides fatty acids rodentmilk adipose tissue * diet A L T H O U G H SOME INFORMATION (1-6) is available on the fatty acid composition of rodent milk, little is known of the composition of the intact triglycerides, which we have therefore analyzed by GLC. Much of our present knowledge of the biosynthesis of milk fats has been derived from studies on rodent mammary tissue (7-12), but few workers have related results obtained in vitro to the fatty acid composition of the milk of the species under investigation. Abbreviations and terminology : GLC, gas-liquid chromatography; C4-Cl8, fatty acids with 4 to 18 carbon atoms; Cz4-Cs6, triglycerides with a total number of acyl carbon atoms of 26 to 56; 8-8-8 and 8-10-8, etc. refer to triglycerides with three C8, or two C8 and one (2x0 fatty acids per molecule, respectively. Note. Rabbits are included here in the order of Rodentia, though they may be considered as a distinct order, the Lagomorpha.
Lipids, 1986
A sensitive and accurate method for detection and quantitation of deuterated fatty acids in the presence of large amounts of unlabeled fatty acids is described using mass fragmentography in combination with the preparation of tertiarybutyldimethylsilyl esters (t-BDMS). The method has been applied to determination of deuterated stearic, oleic, elaidic and linoleic acids in human plasma lipoproteins following duodenal perfusion with a micellar mixture of acids. Over a concentration range of 10-1000 ng/ ml, the average coefficient of variation for the linoleate was 3% and for the oleate (elaidate} ester was 2%.