AQA AS Biology

Revision Notes

1.2.4 Biochemical Tests: Lipids

Biochemical Tests: 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

2.1 Emulsion test, downloadable IGCSE & GCSE Biology revision notes

The Emulsion test for lipids forms a milky colour

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