A simple, specific spray for the detection of phospholipids on thin-layer chromatograms.

Chromatographically homogeneous egg lecithin, as determined by TLC on Silica Gel G, has been isolated from crude egg phosphatides by column chromatography on alumina through modification of existing, lengthy methods. The modified method involved application of crude egg phosphatides to a column of alumina in the proportion of 1 g phosphatide/25 g alumina, and elution of the lecithin fraction with the 2-component solvent system chloroform:methanol, 9:1 by vol. This method of purification separated lecithin from other choline and non-choline components of crude phosphatides, avoided overloading of the alumina column, and made unnecessary the need for a second chromatographic fractionation of partially purified lecithin on silicic acid, which is needed in existing methods of purification of lecithin. The use of fresh yolks permitted easier removal of pigment from the final product than was possible with commercially dried yolks. Phosphatides extracted from dried yolks were much more highly colored than were the phosphatides extracted from fresh yolks and the color presisted through chromatography on alumina. The fatty acid/phosphorus molar ratio of the purified lecithin was 2.00, which is the theoretical FA/P molar ratio of phosphatidylcholine; other materials with this ratio were not present.

Chromatographically homogeneous lecithin from egg phospholipids.

Publisher Summary This chapter discusses the chemical analysis of microbial cells. The preparation of material for analysis is discussed, because changes in the chemical composition of cells may occur as a result of the washing and storage conditions used. Wet- and dry-weight determinations of bacterial samples and assay of total cell numbers are described, because analytical results must refer to one or other of these values. Selection of an analytical procedure is a subjective process, because the number of suitable methods is large and each will have different merits and defects. Primary considerations are sensitivity, specificity, reproducibility, and absolute accuracy. Automatic methods for performing biochemical analyses, already widely accepted in hospitals and in industry, are beginning to make their way into the research laboratory. All automatic analyzers developed so far may be classified as either “continuous-flow” or “discrete” types. All of them use colorimetric methods exclusively and contain some form of automatic colorimeter for final read-out. The first and best-known is the Technicon “AutoAnalyzer,” which is of the continuous-flow type.

Chapter III Chemical Analysis of Microbial Cells

Chromatographic separation, identification, and analysis of phosphatides

Dynamics of the Hydrocarbon Layer in Liposomes of Lecithin and Sphingomyelin Containing Dicetylphosphate

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Phospholipids. 3. On the chromatographic separation of glycerophospholipids.

/pdf/phospholipids-4-on-the-composition-of-hen-s-egg-21wyrr4fg8.pdf

Phospholipids. 4. On the composition of hen's egg phospholipids

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Phospholipins. 1. Partition chromatography of egg-yolk phospholipins on cellulose

1. Polyacids interact with albumin in salt-free solutions to prevent coagulation of the protein by heat. Polyphosphates (nucleic acids), polysulphates (heparin and dextran sulphate) and polyearboxylates (alginic acid and bacterial polyglutamic acid) were all effective. Effects on optical rotation of the albumin were also demonstrated. 2. The protecting agent acts by preventing the coagulation of the albumin, although denaturation occurs to some extent. The molecular size of the protecting agent seems of less importance than the number of acid groups in determining the degree of protection. This work was carried out in the laboratories of the Birmingham branch ofthe British Empire Cancer Campaign.

Phospholipids. 2. Estimation of amino nitrogen in intact phospholipids.

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D. N. Rhodes

Papers

Phospholipids. 3. On the chromatographic separation of glycerophospholipids.

Phospholipids. 4. On the composition of hen's egg phospholipids

Phospholipins. 1. Partition chromatography of egg-yolk phospholipins on cellulose

Phospholipids. 2. Estimation of amino nitrogen in intact phospholipids.

Phospholipids. 5. The effect of cod-liver oil in the diet on the composition of hen's egg phospholipids.