The aim of the course is to provide students with practical knowledge necessary for extraction and analysis of neutral- and/or phospholipids from biological samples.
The course covers methods for lipid extraction from tissues and cell cultures. The obtained lipid extracts are suitable for further analysis by various techniques including Thin-Layer Chromatography (TLC, covered in this course) and HPLC-MS (Lipidomics). Special attention will be given to common pitfalls in lipid analysis.
The purpose of all lipid extraction procedures is to separate cellular or liquid lipids from the other constituents, proteins, polysaccharides, small molecules (amino-acids, sugars, etc.) and also to preserve these lipids for further analysis. The ideal solvent for lipid extraction would extract all lipid components completely from a sample, while leaving all other components behind. In practice, the efficiency of solvent extraction depends on the polarity of the lipids present compared to that of the solvent.
Polar lipids (such as glycolipids or phospholipids) are more soluble in polar solvents (such as alcohols) than in non-polar solvents (such as hexane). Non-polar lipids (such as triacylglycerols) are more soluble in non-polar solvents than in polar. The fact that different lipids have different polarities means that it is impossible to select a single organic solvent to extract all lipids in a single step. The total fat content determined by solvent extraction thus depends on the nature of the organic solvent used for the extraction: the total fat content determined with one solvent may differ from the content determined with another solvent.
Upon individual request
Dr. Chris van de Lest (C.H.A.vandeLest@uu.nl)