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Lab I: TLC Analysis of Analgesic Drugs

Pre-lab Work

Reading Assignment:

  1. Thin-Layer Chromatography
    Mohrig, Technique 15, pp.177-189 & Appendix


Experimental Work Objectives:

  • To resolve mixtures of unknown commercial painkillers using TLC.
  • To identify the individual components of each unknown mixture and to identify the unknown commercial painkillers.


Experimental Procedure
Perform the procedure for Thin Layer Chromatography as described in the Appendix.

Table 1: Commercial painkillers and their components

 

Components of Commercial Painkillers (Standards)

Acetaminophen

Aspirin

Caffeine

Ibuprofen

Anacin

 

X

X

 

Bufferin

 

X

 

 

Excedrin (extra-strength)

X

X

X

 

Tylenol

X

 

 

 

Motrin

 

 

 

X

Molecular Structure

of

the compounds

 

 

 

 

 

Printable version of Table 1

Post-lab

  1. Draw the structures for each of the three analgesics and caffeine. (Complete Table 1)
    [See Mohrig, Technique 4, pp. 34-38. Reference the source for the structures of these compounds.]
  2. What were the unknown commercial painkillers and what are the individual components in each?
  3. Knowing how the individual components of the painkillers were separated on the TLC plate, what do you know about how they differ in polarity?
  4. Discuss any errors in your experiment and state what you would do differently if you were to do this lab again.