NAME:_______________________
Testing for Lipids
Purpose: To become familiar with two tests to indicate the presence of lipids (fats).
Materials:
 4 test tubes
 Test tube stoppers
 Sudan IV indicator
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Test tube rack
Brown paper bag
Medicine dropper
Procedure – Part 1
1. Measure approximately 3ml each of distilled water, vegetable oil, skim milk, and
whipping cream
2. Add six drops of Sudan IV indicator to each test tube
3. Place stoppers on the test tubes and shake them vigorously for 2 minutes
4. Record the colours of the mixtures on a chart
Observations – Part 1
Substance
Colour after adding Sudan IV and mixing
Water
Vegetable oil
Skim milk
Whipping cream
Procedure – Part 2
1.
2.
3.
4.
5.
On the brown paper bag draw five circles about 5 cm in diameter.
Label each circle as nothing, water, vegetable oil, skim milk and whipping cream.
Place one drop of each solution in the middle of their corresponding circle.
When the water has evaporated, hold all the papers to the light and observe.
Record whether or not the papers appear translucent (can see through it).
Observations – Part 2
Substance
Water
Vegetable oil
Skim milk
Whipping cream
Appearance on paper
Conclusions – For Both Parts
1. Describe two positive tests for the presence of lipids.
2. Explain the advantage of using two separate tests for lipids.
3. Create a chart that shows which of the substances tested are a saturated fat or an
unsaturated fat.
4. Which substance served as a control?
5. Predict the results of the lipid tests on samples of butter and margarine.