Ethanol emulsion test for lipids
An emulsion test allows you to check whether a substance might be a lipid. The test uses the fact that lipids can dissolve in ethanol but not water:
- Grind the sample and place in a clean, dry test tube.
- Pour 95% ethanol into the tube. Shake vigorously.
- Pour this solution into another test tube of distilled water.
Lipids can dissolve in ethanol but not water.
If the sample contains lipids, the lipids will form tiny lipid globules in the mixture called an emulsion. This appears as a cloudy white layer in the mixture.
If the mixture doesn't contain lipids, the mixture will stay colourless.