Glycerolipids glycerophospholipids

More complex structures, often related to natural products are prepared by organic synthesis. Among them can be mentioned (f )-3-hydroxytetradecanoic acid (the double-tail hydrophobic moiety of lipid A), sphingosine derivatives related to the ceramides or 1,2- and l,3-dialkyl(acyl)glycerols related to glyco-glycerolipids, glycerophospholipids, and GPI anchors of membrane proteins. The preparations of the above derivatives were reported several years ago but some improvements have been published more recently. 

This review is restricted largely to discussion of LC/MS and LC/MS/MS combinations for glycerolipid, glycerophospholipid and sphingolipid analyses. Recent applications to complex fatty acids and other non-glycerolipids are discussed as required for structural analyses of glycerolipids and sphin-golipids. 

Arachidonic acid is an important fatty acyl component of the lipidome that is present as the free fatty acid in the plasma as well as the esterified form in sterol lipids, and at the sn-2 position of glycerolipids and glycerophospholipids... 

By far the largest group of plant acyl lipids is based on the trihydric alcohol glycerol and includes acyl glycerols, glycerophospholipids, and glyco-glycerolipids. 

The use of stereospecitic numbering (sn) method for the glycerol-based lipids (e.g., glycerolipids and glycerophospholipids) [3], Acyl or alkyl chains are typically linked to the i -l and/or sn-2 positions of glycerol, with the exception of some lipids that contain three acyl or alkyl chains or contain more than one glycerol group and archaebacterial lipids in which sn-2 and/or sn-3 modification occurs. 

The following are a few examples to demonstrate how an elucidated fragmentation pattern can be used for identification of individual species of a lipid class present in biological samples by MDMS-SL. These examples well represent different lipid classes (e.g glycerophospholipids, sphingolipid, and glycerolipids), different mass levels (from low abundance to abundance), different polarities (Ifom polar to non-polar), etc. 

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