O-methyl oximes of sugars. Analysis as O-trimethylsilyl derivatives by gas-liquid chromatography and mass spectrometry

The mass spectra of aldoses, partially methylated aldoses, deoxyaldoses, and ketoses containing 3-7 carbons, were recorded on the ethers of the trimethylsilyl O-methyl oxime derivatives. Each compound gave a distinctive spectrum indicating the carbon-chain length and the location of substituents. The gas-liquid chromatographic properties of most compounds in this study were also examined. © 1973

Identification of 2-hydroxy fatty acids in complex mixtures of fatty acid methyl esters by Mass chromatography.

Repetitive mass spectrometric scanning of gas‐liquid chromatographic effuents at short (6 to 15 s) intervals, with a digital computer for data acquisition, reduction and display, allows plots (mass chromatograms) to be made of the intensities of specific ion fragments. Plotting of m/e values characteristic for certain classes of compounds and/or individual components reveals the location of constituents in the gas chromatogram. This technique was applied to the identification of trimethylsilyl derivatives of unsubstituted and 2‐hydroxy fatty acid methyl esters in mixtures obtained from acid catalyzed methanolysis of cat brain galactocerebrosides. The plot of total ionization intensity vs scan number generated the gas‐liquid chromatogram. Mass chromatograms of m/e 73 and [M – 59]+ gave the locations in the gas‐liquid chromatogram of the hydroxy fatty acid derivatives, and mass chromatograms of m/e 74 and [M]+ located the unsubstituted fatty acid derivatives. Integrated ion intensities were used to determine the composition of the mixture of fatty acids. Copyright © 1974 John Wiley & Sons, Ltd

Monoglucosyloxyoctadecenoic acid--a glycolipid from Aspergillus niger.

Details are given of the purification and structure of an apparently novel type of fungal glycolipid. It was obtained in a relatively pure form by fractionation of the acetone-soluble lipids of Aspergillus niger by Florosil column chromatography and finally purified by preparative thin-layer chromatography. On the basis of the evidence obtained from mass spectroscopy, infrared spectroscopy, chromatographic procedures, and the alkaline stability of the glycolipid, we propose that it is a monoglucoside of a trans-2-hydroxy octadecenoic acid. The acidic nature of the glycolipid, combined with its relative prominence (about 6 % of the total lipid), when phospholipid was depleted (less than 2% of the total lipid), indicated that it had an important role in the structure and function of the fungal membranes. © 1972, American Chemical Society. All rights reserved

On the structure of cytolipin R, a ceramide tetrahexoside hapten from rat lymphosarcoma

Cytolipin R, a ceramide tetrahexoside isolated from rat lymphosarcoma, was studied by sequential hydrolysis with specific glycosidases which revealed the anomeric configurations of the glycosidic bonds. Sugar linkages were established by combined gas liquid chromatography and mass spectrometry of the partially methylated alditol acetates prepared after permethylation and hydrolysis of the intact lipid. Results indicated the structure of cytolipin R to be N acetylgalactosaminyl (β1→3) galactosyl (α1→3) galactosyl (β1→4) glucosyl ceramide. Cytolipin K (globoside I) differs in having a galactosyl (α1→4) galactosyl internal linkage, and this difference must account for the immunological differences between cytolipin K and cytolipin R