Direct transesterification of all classes of lipids in a one-step reaction.

For the characterization of organic substances in gas chromatography a number termed «retention index» is proposed. A simple relation exists between the retention index of a compound on a non-polar stationary phase and its boiling point.

Gas‐chromatographische Charakterisierung organischer Verbindungen. Teil 1: Retentionsindices aliphatischer Halogenide, Alkohole, Aldehyde und Ketone

Volatile Fatty Acid Analyses of Blood and Rumen Fluid by Gas Chromatography

Fatty acids have been used as qualitative markers to trace or confirm predator-prey relationships in the marine environment for more than thirty years. More recently, they have also been used to identify key processes impacting the dynamics of some of the world's major ecosystems. The fatty acid trophic marker (FATM) concept is based on the observation that marine primary producers lay down certain fatty acid patterns that may be transferred conservatively to, and hence can be recognized in, primary consumers. To identify these fatty acid patterns the literature was surveyed and a partial least squares (PLS) regression analysis of the data was performed, validating the specificity of particular microalgal FATM. Microalgal group specific FATM have been traced in various primary consumers, particularly in herbivorous calanoid copepods, which accumulate large lipid reserves, and which dominate the zooplankton biomass in high latitude ecosystems. At higher trophic levels these markers of herbivory are obscured as the degree of carnivory increases, and as the fatty acids originate from a variety of dietary sources. Such differences are highlighted in a PLS regression analysis of fatty acid and fatty alcohol compositional data (the components of wax esters accumulated by many marine organisms) of key Arctic and Antarctic herbivorous, omnivorous and carnivorous copepod species. The analysis emphasizes how calanoid copepods separate from other copepods not only by their content of microalgal group specific FATM, but also by their large content of long-chain monounsaturated fatty acids and alcohols. These monounsaturates have been used to trace and resolve food web relationships in, for example, hyperiid amphipods, euphausiids and fish, which may consume large numbers of calanoid copepods. Results like these are extremely valuable for enabling the discrimination of specific prey species utilized by higher trophic level omnivores and carnivores without the employment of invasive techniques, and thereby for identifying the sources of energetic reserves. A conceptual model of the spatial and temporal dominance of group-specific primary producers, and hence the basic fatty acid patterns available to higher trophic levels is presented. The model is based on stratification, which acts on phytoplankton group dominance through the availability of light and nutrients. It predicts the seasonal and ecosystem specific contribution of diatom and flagellate/microbial loop FATM to food webs as a function of water column stability. Future prospects for the application of FATM in resolving dynamic ecosystem processes are assessed.

Fatty acid trophic markers in the pelagic marine environment.

Chromatographic separation, identification, and analysis of phosphatides

Industry has long used charcoal or other solid absorbents in columns for cleaning gas streams or for solvent recovery, and more recently Turner (1943), Claesson (1946), Glueckauf, Barker & Kitt (1949), Phillips (1949) and Turkel'taub (1950) have used charcoal in gas chromatograms for the analysis of hydrocarbons and esters. Gas-liquid scrubbing columns have been used in industry for many years but, though Martin & Synge (1941) suggested the use of gas-liquid partition chromatograms for analytical purposes, no work has been reported along these lines. This paper presents modifications necessary to the theory of Martin & Synge (1941) to allow for the compressibility of the mobile phase and describes the application ofthe gas-liquid partition chromatogram to the separation of volatile fatty acids. The separations obtainable by this method are essentially parallel to those obtainable by distillation, but good separations can be achieved much more easily and it is possible to work with very much smaller quantities. In fact, the lower limit of quantity of material used is determined only by the efficiency of detection. In general, far less trouble from azeotrope formation is to be expected, since the concentrations of the substances to be separated in the liquid phase are always low and it may be possible to choose a liquid phase which associates only with one component of the azeotrope. Work on a preparative scale, though theoretically possible, is likely to be inconvenient because of the bulk of the apparatus. The method of detection described here is acid-base titration, but many methods of detecting changes in the composition ofa gas stream could be used and it is intended in future publications to explore some of these, which should extend the range of application to all substances capable of being distilled at the pressure of a few mm. of mercury. In suitable cases the gas-liquid partition column has two principal advantages over the ordinary liquid-liquid partition column: (a) the low viscosity of the mobile phase allows relatively longer columns to be used with a corresponding gain in efficiency and (b) in general it is easier to detect changes in composition of a gas than of a liquid stream. A THEORY OF GAS-LIQUID PARTITION CHROMATOGRAPHY

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Gas-liquid partition chromatography: the separation and micro-estimation of volatile fatty acids from formic acid to dodecanoic acid

In the preface to the Second edition, we made a prediction that many exciting developments would take place in the coming years that would change the face of a new edition. This has indeed been the case and the current edition reflects these new advances. Our picture of the structure of the fatty acid synthetase has changed dramatically, bringing a new concept in enzymology - the multicatalytic polypeptide chain. This new knowledge owes much to the exploitation of genetic mutants, the use of which is undoubtedly going to extend into many other areas of lipid biochemistry. An understanding of the control of lipid metabolism has also advanced considerably during the last decade and we have tried to reflect that here, although it will be some years before a truly integrated picture can be obtained. For this reason we have continued to deal with the control of particular aspects of lipid metabolism - fatty acids, triacylglycerols, lipoprotein- in the specific chapters but we can foresee the time when a chapter on the overall integration of lipid metabolism will be appropriate and feasible. As a particular example, the exciting new concepts of the control of cholesterol metabolism in specific tissues via the interaction of low density lipoproteins with cell surface receptors have been described in Chapter 6.

Lipid biochemistry: an introduction

Gas-liquid chromatography: the separation and identification of the methyl esters of saturated and unsaturated acids from formic acid to n-octadecanoic acid

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A. T. James

Papers

Gas-liquid partition chromatography: the separation and micro-estimation of volatile fatty acids from formic acid to dodecanoic acid

Lipid biochemistry: an introduction

Gas-liquid chromatography: the separation and identification of the methyl esters of saturated and unsaturated acids from formic acid to n-octadecanoic acid

Gas-liquid partition chromatography: the separation and micro-estimation of ammonia and the methylamines.

The biosynthesis of long-chain fatty acids by lettuce chloroplast preparations