PubMed · 4736421
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N Sakauchi. 1973. [Gas chromatography].. https://pubmed.ncbi.nlm.nih.gov/4736421/
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The insolubility of calcium phosphate in water is a significant stumbling block in the chemistry required for the origin of life. The discovery of alkyl phosphonic acids in the Murchison meteorite suggests the possibility of delivery of these water-soluble, phosphorus-containing molecules by meteorites or comets to the early Earth. This could have provided a supply of organic phosphorus for the earliest stages of chemical evolution; although probably not components of early genetic systems, phosphonic acids may have been precursors to the first nucleic acids. Here we report the synthesis of several phosphonic acids, including the most abundant found in the Murchison meteorite, by ultraviolet irradiation of orthophosphorous acid in the presence of formaldehyde, primary alcohols, or acetone. We argue that similar reactions might explain the presence of phosphonic acids in Murchison, and could also have occurred on the prebiotic Earth.
This article discusses the methods most commonly employed in the analysis of the triacylglycerols (TAGs) in natural fats and considers the main advantages and disadvantages of each and the techniques for optimising analytical conditions. Complete analysis of the composition of a natural fat calls for a method of extracting and purifying the triglyceride fraction, normally by preparatory thin-layer and column chromatography. Determination of the individual components of triglyceride mixtures still entails certain difficulties, namely, the separation and identification of the TAGs in natural fats. High-performance liquid chromatography (HPLC) offers significant advantages over gas and thin-layer chromatography. Many workers have developed non-aqueous, reversed-phase HPLC systems capable of successfully resolving complex mixtures of TAGs, and combining reversed-phase (RP) HPLC and argentation chromatography may improve the results. Identification of the TAGs separated by HPLC becomes an extremely complex task if many different fatty acids are involved and if the sn-stereoscopic positions on the glycerol are to be determined. Enzymatic analysis and chiral-phase chromatography are capable of localising fatty acids on the TAG molecule. In closing, some of the most interesting biomedical applications of TAG analysis are summarised.
Most lipids are best characterized by their fatty acids which differ in chain length, the degree of unsaturation, configuration and position of the double bonds, and the presence of other functionalities. The fatty acid profiles are currently most frequently determined by capillary gas chromatography of the methyl esters which are prepared by a variety of methods. These are discussed with an emphasis on more recent developments, along with the stationary phases used for the separations and the methods employed for identification of the fatty acids. HPLC is applied less frequently for ascertaining fatty acid profiles than GC, but a very large number of derivatives for ultraviolet and fluorescence detection have been proposed. This method continues to evoke increasing interest, particularly in conjunction with fluorescence detection. This technique enables attainment of greater sensitivities than with standard GC methods employing flame ionization detection. Extensive applications of it to the analysis of free fatty acids in blood and other biomedical samples are clearly discernible. Other methods, including supercritical fluid chromatography, have found only limited application for fatty acid profiling.