School of Chemical Engineering and Chemistry
Experiment 5
TEST FOR LIPIDS
Introduction
The student shall provide his or her own introduction to the experiment.
Objectives
The experiment aims for the student to be able to characterize the lipid samples as well as brought samples that contain lipids. The various tests will show how lipids are similar in their unique characteristics.
Methodology
Materials
Chloroform
Distilled water
Hexane
Sudan red (IV) dye
Unglazed paper
CH
2
Cl
2
Br
2
in CH
2
Cl
2
Samples
Oleic acid
Stearic acid
Lauric acid
Olive oil
Coconut oil/palm oil/ any vegetable oil
Procedure
Solubility test
1. Obtain three test tubes. To one of the tubes, add 5 ml of water. To the other tube, add 5 ml of chloroform. To the last, add 5 mL of hexane.
2. Add a few drops of a sample to each tube.
3. Repeat the procedure for the other samples.
Grease-spot test
1. Obtain a piece of unglazed paper.
2. Use an eyedropper to add a drop of the sample near a corner of the piece of paper.
3. Add a drop of water near the opposite corner of the paper.
4. Let the fluids evaporate
5. Look at the paper as you hold it up to a light.
Test for unsaturation
1. Transfer four drops of the fat sample to the test tube.
2. Add 1 mL of CH
2
Cl
2
and shake/swirl to dissolve.
3. Add Br
2
/CH
2
Cl
2
solution to the fat in the test tube one drop at a time. Keep adding the bromine solution until the red color no longer disappears.
Sudan Red test

1. Obtain four test tubes for each of your samples. Label them 1A, 1B, 1C, and 1D.
2. Place 1 ml of the sample in 1A, 1B, and 1C
3. Add 1 ml of water to 1D.
4. Add five drops of Sudan Red dye to each of the test tubes. Observe the results.
5. Repeat the procedure for each of the samples.
Questions for consideration in the final report
1. What can you comment and conclude about the solubility of lipids in solvents of different properties?
2. What happens in the grease spot test? What’s the difference observed between water and the lipid samples?
3. What happens in the unsaturation test? What made the dark color disappear? Why did it not disappear in some of the other samples?
4. By what mechanism does the Sudan Red dye elicit the positive result?