Because of their non-polar properties, lipids are easily separated from other
biological materials by extracting into organic solvents such as ether,
chloroform or benzene. However, in the tissue samples, lipids generally occur
in close association with proteins and polysaccharides. In order to break these
complexes, it is often necessary to employ extraction conditions that denature
or disrupt the associated proteins or polysaccharides. Various solvents or
solvent combinations have been suggested as extractants (see Table 3.1). In
this practical, the extraction method based on chloroform: methanol—as
suggested by Folch et al. (1957)—will be used to extract lipids from pork liver.
The extracted lipids will then further separated and analysed by thin layer
chromatography (TLC).