Biochemical Tests: Lipids (AQA A Level Biology)

Emulsion Test for Lipids

• The emulsion test that can be carried out quickly and easily in a lab to determine if a sample contains lipids

• This test is qualitative - it does not give a quantitative value as to how much lipid may be present in a sample

• Lipids are nonpolar molecules that do not dissolve in water but will dissolve in organic solvents such as ethanol

• Add ethanol to the sample to be tested, shake to mix and then add the mixture to a test tube of water

• If lipids are present, a milky emulsion will form (the solution appears ‘cloudy’); the more lipid present, the more obvious the milky colour of the solution

• If no lipid is present, the solution remains clear

The Emulsion test for lipids forms a milky colour.