Experiment 11b: Isolation of Caffeine from a Tea Bag
The objective of this experiment is to extract caffeine from tea bags using the method of extraction. After the caffeine is extracted it is then compared to the nutritional facts amount per serving on the tea bags box.
50.0 m L graduated cylinder
150.0 mL beaker
2-glass stirring rod
2-50.0 mL Erlenmeyer flasks
hot plate (Corning PC-420P)
electronic scale (S/N: 8330280171)
stapler with at least 2 staples
test tube rack
hot plate tile
centrifuge (Becton Dickinson; Clay Adams Brand Compact II Centrifuge) 9.
halogenated waste container
filter paper (Double Rings qualitative 9.0 cm CAT# 1101090) 3.
Fisher Science Education
Black Tea Bags
Plug in hot plate and set to 220.0 oC
While waiting for the hot plate to heat up, measure 50.0 mL of distilled water in a 50.0 mL graduated cylinder. Pour into a 150.0 mL beaker. 3.
Place the 150.0 mL beaker from step 2 on the hot plate to begin heating the distilled water. 4.
Put a weighing boat on an electric scale and tare it.
Remove staples from the 2 tea bags and pour the tea into the weighing boat from step 4. Record the mass of the tea. 6.
Evenly distribute the tea back into the tea bags and staple them closed. 7.
Put the tea bags into the 150.0 mL beaker on the hot plate so that they are in the hot water. 8.
Allow time for the tea to "brew" or allow the water to turn a very dark brown color. Stir occasionally with a glass stirring rod. 9.
While time for the tea to brew, acquire 6 test tubes and place them in a test tube rack. 10.
Once the tea has turned the water a very dark brown, place the 150.0 mL containing the tea on the hot plate tile. 11.
Allow the tea and the beaker to cool. Squeeze out any tea from the bags into the beaker and dispose of the bags in the garbage. 12.
Using a clean glass pipette, disperse the tea evenly into the 6 test tubes. 13.
Put the entire test tube rack along with the test tubes into the refrigerator, until completely cool. 14.
Once cool, bring the test tube rack back to the working space. 15.
Using a clean glass pipette, add an equal amount (as the amount of tea) of methylene chloride to each of the test tubes. 16.
Plug each of the test tubes with rubber stoppers.
Shake up each of the test tubes.
Vent the shaken test tubes by taking out the rubber stoppers to release the pressure and then put them back in. 19.
Place the test tubes in the slots of the centrifuge.
Close the lid and run the centrifuge for 1.0 minute.
Put test tubes back into the test tube rack.
Use a glass Pipette to extract the bottom layers from each of the test tubes and transfer to a clean 50.0 mL Erlenmeyer flask. The same pipette from step 15 may be used because the bottom layer is methylene chloride.
Dry the methylene chloride in the 50.0 Erlenmeyer flask by adding sodium sulfate and stirring/swirling until the substance is free flowing. 24.
Using the electronic scale, weigh a clean 50.0 mL Erlenmeyer flask and record its mass. 25.
Using a glass funnel and a piece of filter paper, make a filter system by fitting the filter paper inside the cone of the funnel. Put the funnel into the Erlenmeyer flask from step 24.
Pour the dry methylene chloride from step 23 through the filter setup in step 25 to remove the sodium sulfate from the...
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