How to test for lipids

Written by carrie perles Google
  • Share
  • Tweet
  • Share
  • Email

The two main ways to test for lipids in a sample substance is through the Sudan Red test and the Grease Spot test. Sudan Red is a dye that is lipid soluble. Therefore, when Sudan Red is added to a sample that contains lipids, the dye will colour the lipids red. The Grease Spot test can also be used identify the presence of lipids in a sample. Lipids make unglazed paper, such as the outside of a paper bag, translucent.

Skill level:

Things you need

  • Sample for Testing
  • Beakers or Droppers
  • Sudan Red
  • Brown Paper Bag
  • Oil
  • Water

Show MoreHide


  1. 1

    Use a cotton swab to apply a few drops of the sample to the paper bag.

  2. 2

    Allow the sample to dry on the bag for several minutes.

  3. 3

    Hold the paper bag up to a light after the sample has dried completely. If a grease spot remains, the sample contains lipids.

  1. 1

    Measure 2ml of oil and 2ml of water.

  2. 2

    Add the oil and water to the test tube.

  3. 3

    Add 3 drops of Sudan Red.

  4. 4

    Shake the test tube and observe. The Sudan Red will colour any lipids in the sample.

Tips and warnings

  • During the Grease Spot test, make sure to allow all spots to dry thoroughly. Otherwise, you may think that a wet spot is really a grease spot.
  • Be careful with the Sudan Red, because it can stain clothing.

Don't Miss

  • All types
  • Articles
  • Slideshows
  • Videos
  • Most relevant
  • Most popular
  • Most recent

No articles available

No slideshows available

No videos available

By using the site, you consent to the use of cookies. For more information, please see our Cookie policy.