Glycolipids individual, separation

Glycolipid analysis. Gangliosides were extracted with chloroform-methanol (2 1), purified on Sephadex G-25 columns and separated into individual species by thin-layer chromatography as described previously (12). 

The positive-ion MALDI-TOF mass spectra of brain are dominated by PC, LPC and SM, whereas PI is the most abundant negatively charged PL. In order to be able to detect further lipid species, however, a previous separation of the total brain extract into the individual lipid classes is necessary [88]. Because of the rapid performance and simple equipment involved, TLC can be used advantageously when only small amounts of lipids are necessary for subsequent analysis by MS [132]. Indeed, by using a careful sample preparation and suitable TLC conditions, even minor glycolipids can be detected and investigated [133]. 

Glycolipids are often difficult to separate completely by one-dimensional TLC because of their complex array of oligosaccharides. Therefore, a variety of 2-D TLC procedures have been devised to separate individual glycolipids and phospholipids on the same plate. Glycolipids of plant and bacterial origin are usually separated on silica gel G using the 2-D system first described by Nichols (100). 

Ideally, It would be preferable if lipids could be separated into individual molecular species without being modified in any way so that, for example, the biosynthesis or metabolism of each part of the molecule could be studied with isotopically labelled components. The technical problems of the analysis can often be greatly reduced, however, if the polar parts of complex phospho- and glycolipids are... 

---