Tlc Lab

In this TLC lab, we explored the relative polarities of Acetylsalicylic Acid, Ibuprofen, Acetaminophen, and Caffeine based on their functional groups. The most overall polar analgesic is considered to be the analgesic that contained the most polar function groups. The amine and amide functional groups are the most polar. In this experiment, we found that both these functional groups are found in Caffeine. As a result, Caffeine was the most polar out of Acetylsalicylic Acid, Ibuprofen, Acetaminophen, and Caffeine. Aside from Caffeine, Acetaminophen has one amide functional group. This makes it the second most polar analgesic. In addition, Acetylsalicylic Acid has an ester group. Since ester group is not as polar as either amine or amide groups,
It is important to note that acetic acid is the non-polar component of the experiment. On the other hand, the stationary phase corresponded to the Silicon on the TLC plate. From the dipole in Silicon and Oxygen bonds, this is regarded as the polar component of the experiment. Compared to the mobile phase, the stationary phase results in the polar functional groups to be a stronger attractant. As a result, the most polar functional groups will travel up less the TLC plate. Due to the non-polar compounds not sticking to the stationary phase as strongly as the polar compounds do, non-polar compounds should have a larger Rf value than polar compounds. As previously stated, the least to most polar is Ibuprofen, Acetylsalicylic Acid, Acetaminophen, and Caffeine respectively. This shows that ideally, Caffeine has the lowest Rf value while Ibuprofen should have the largest Rf value. In the Observations section, we calculated that Ibuprofen’s Rf value is .81, Acetylsalicylic Acid’s Rf value is .64, Acetaminophen’s Rf value is .46, and Caffeine’s Rf value is .10. This illustrates that the Rf values trend match the the four analgesics’ polarity
We used this specific eluent because it is polar. Since the analgesics used in this lab contained different functional groups, some were more polar than others. So, the polar eluent with a non-polar TLC plate assists in illustrating the different polarity strengths and determining the analgesic drugs in a mixture. Furthermore, the acetic acid component of the eluent used helps remove the excessive Ibuprofen and Acetylsalicylic Acid. This is done by restraining their ionization. Overall, ethyl acetate containing 0.5% acetic acid was effective because the various analgesics in Anacin, Excedrin, Motrin, and No-Doz were all clearly separated and