VCL 1-1: Using Thin Layer Chromatography
6. Before waiting too long, perform a TLC measurement by clicking on the TLC jar (located to the right
of the cork ring) and drag the TLC plate and drop it on the round bottom flask. A window should now
open showing the TLC results. In the starting material lane (the left lane) you should see two large
spots near the bottom and in the reaction lane (the right lane) you should see the same two spots.
Why are the spots the same for both the right and left lanes?
7. Close the TLC window and now advance the reaction forward 15 minutes (or you can just wait 15
minutes) by advancing the time on the laboratory clock. This is done by clicking on the appropriate
button under the minutes, tens of minutes, or hours digits on the clock. Now perform a new TLC
measurement on the reaction mixture.
What is the new spot?
What has happened to the size of the starting material spots? Why?
8. Close the TLC window again and now advance the laboratory time forward until all of the starting
materials have been consumed. You will need to monitor the reaction with TLC measurements until
you observe that the starting materials have been consumed.
How much time did it take to complete the reaction?
What are the Rf values for the starting materials and product?
What can you say about the relative polarities of the starting materials and the product?
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