A simplified procedure for the quantitative extraction of lipids from brain tissue

A method is described for the quantitative extraction of lipid from brain tissue with chloroform/methanol (C/M) that eliminates secondary purification of the lipid extract by dextran-gel chromatography or aqueous washing of the organic extract. Nonlipid substances that generally contaminate C/M lipid extracts are separated by pre-extraction of the tissue with dilute (0.25%) aqueous acetic acid. The residual tissue is extracted twice with 40 volumes of C/M (1:1, v/v). Approximately 97% of the lipid is recovered in these extractions. A third extraction which yields ca. 1% more lipid is performed if the process is discontinued at this stage in a shortened version of the method. The remainder of the lipid is recovered after treatment of the tissue with 1 N HC1 by two additional extractions, the first with 40 volumes of C/M (1:2, v/v) and the second with 40 volumes of methanol. The method, which was demonstrated with pig brain, gave a complete extraction of the lipid, including gangliosides, free of nonlipid substances.