Polar lipids are generally extracted from dry cell material using chloroform:methanol:0.3% NaCl (1:2:0.8 v/v/v). This may be carried out by adding 9.5 ml of this mixture to 100 mg of freeze dried cells, or by adding a suitable amount of chloroform, methanol and 0.3% NaCl to the cell material, or to the aqueous methanolic phase remaining from the lipoquinone extraction.
1. The aqueous methanolic phase (4 ml total volume), together with the cell material from the lipoquinone analysis, is diluted with 5.5 ml of Chloroform:Methanol (2.5:3.0 v/v) to give a chloroform, methanol, 0.3% NaCl (1:2:0.8 v/v/v) mixture.
2. The mixture is placed in a 15 ml bottle with a teflon lined screw cap (check that the magnetic stirrer is in the bottle), gassed briefly with nitrogen, sealed and heated for 15 min at 80 C (with occasional shaking).
3. Allow the mixture to cool to room temperature on a magnetic stirrer. Check that the mixture is homogeneous, the presence of excess hexane will cause phase separation and may be overcome by adding a small amount of methanol until a homogeneous mixture is obtained.
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