Thin Layer Chromatography Lab Report

Utilizing the techniques of acid-base extraction and Thin Layer Chromatography we were able to extract the three active components of Excedrin and confirm the identity of each compound. The three active components of Excedrin- aspirin, acetaminophen, and caffeine- all have varying acidities and polarity which allowed for the successful usage of acid-base extraction and TLC respectively. Acid-base extraction was applied by adding our compound to a basic solvent in order to isolate the components by turning them into water-soluble ionic salts. Then, by adding a stronger acid, like HCl, our components were protonated and precipitated out of the aqueous solvent. This creates crystals with can be analyzed with TLC. We extracted the components using

TLC works based on different molecules travelling different speeds up a TLC plate based on polarity. TLC can be used to identify molecules and check purity. Since the three active components in Excedrin have different polarities, TLC was useful in identifying our samples based on how fast they ran up the TLC plate. We applied TLC by co-spotting our samples with the stock-room version of what believed them to be to see if they travelled the same distance up the plate. This application of TLC was useful because it allowed us to conclude the active component of Excedrin in each of our crystals. We were able to conclude that the crystals obtained from the K2HPO4 were aspirin since they both yielded a Rf value of 0.711. We also concluded the KOH crystals were acetaminophen with a shared Rf value of 0.504. Finally, we used TLC to determine the ether crystals were caffeine, yielding a shared Rf value of 0.209. We utilized how the three active components had varying Rf values due to the polarity of the compounds, with the lower Rf values corresponding to more polar molecules, in order to confirm the identity of our