Silver ion chromatography of lipids and fatty acids.

Triacylglycerols (TGs) make up the major part of naturally occurring fats and oils The composition and fine structure of TGs determine to a large extent the functionality of fats and oils as food ingredients and the physiological effects of fats and oils as component of the human diet Analysis of intact TGs is usually performed by chromatographic methods In this article the application of gas-liquid chromatography, high-performance chromatography in normal and reversed phase mode, thin-layer chromatography and supercritical fluid chromatography for the qualitative and quantitative determination of TGs is reviewed Emphasis is put on those factors that are decisive for obtaining reliable quantitative data Furthermore, techniques for the stereospecific analysis of the fatty acid distribution along the glycerol backbone of TGs are presented briefly

Triacylglycerol Profiling by Using Chromatographic Techniques.

The analysis of fatty acids and related materials by gas-liquid chromatography

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.

&High Performance Reversed-Phase Chromatography of Natural Triglyceride Mixtures

Detailed investigation was made of the triacylglycerol structure of native, simulated, and interesterified peanut oils, which had previously been shown to differ markedly in their atherogenic potential. By means of chromatographic and stereospecific analyses, it was shown that the more atherogenic native oil contains a significantly greater proportion of triacylglycerols with linoleic insn-2-position and arachidic, behenic, and lignoceric acids insn-3-position than the synthetic oils. It is suggested that the atherogenicity may arise from a relative metabolic unavailability of the linoleic acid from the native oil, which may be due in part to the presence of long chain saturated acids in the outer position. This might render the oil metabolically more saturated than the interesterified oils of the same total fatty acid composition, which contain a much greater proportion of the linoleic acid in the primary positions of the triacylglycerol molecule. The identification of specific triacylglycerols may allow the experimental testing of this hypothesis by feeding synthetic triacylglycerols incorporating the potentially atherogenic features.

Acylglycerol structure of peanut oils of different atherogenic potential

Triglyceride konnen sowohl mit Hilfe der Umkehrphasen als auch der Silbernitrat-Chromatographie getrennt werden. Bei beiden Methoden treten kritische Partner auf, die durch eine Kombination beider Verfahren weitgehend getrennt werden konnen. Nicht getrennt werden dabei aber isomere Triglyceride. Letztere lassen sich ihrer Struktur nach in verschiedene Klassen aufteilen, wie Stellungsisomere, geometrische Isomere, Isomere mit gleicher Zahl von Doppelbindungen und C-Atomen, aber verschiedenen Fettsauren, sowie Isomere mit stellungsisomeren ungesattigten Fettsauren. Die Schwierigkeiten bei der Trennung dieser Isomeren werden erortert und Beispiele fur die DC-Trennung von Triglyceriden jeder Klasse gezeigt. Die Beispiele an Modellsubstanzen werden erganzt durch die DC-Trennung von Baumwollsaat-, Sonnenblumen-, Oliven-, Erdnus-und Palmkernol.



TLC-Separation of Mixtures of Isomeric and Natural Triglycerides



Triglycerides can be separated by reverse phase as well as by argentation chromatography. In both of these methods critical pairs are formed whose separation can be effected to a large extent by a combination of the two methods. However, isomeric triglycerides can not be separated by the latter procedure. According to their structure, the isomeric triglycerides can be classified into positional isomers, geometric isomers, isomers having the same number of double bonds and C-atoms but containing different fatty acids, and glycerides containing the positional isomers of unsaturated fatty acids. The difficulties involved in the separation of these isomers are pointed out and examples for the TLC-separation of triglycerides of each class are shown. In addition to the resolution of model substances, the TLC-separations of cottonseed, sunflower, olive, peanut and palm kernel oils are given.

H. Wessels

Papers

Die DC‐Trennung von isomeren und natürlichen Triglycerid‐Gemischen