Thin Layer Chromatography Lab Report

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Thin Layer Chromatography Lab Report Miranda Tyree Lab Partner: Caitlin Price TA: Yi Zhou Lab Time: Thursday, 12 pm Lab Room: 207 Date: 09/23/2016 Abstract Experiments were performed to determine the active chemical ingredients in Tylenol and Anacin. The active chemical ingredients were determined by performing thin layer chromatography of four substances: Tylenol, Anacin, acetaminophen, and acetylsalicylic acid. The identity of the ingredients was then confirmed by using the co-spotting thin layer chromatography technique. Tylenol had Rf values of 0.566 and 0.184, Anacin had Rf values of 0.19 and 0.72, acetaminophen had an Rf value of 0.566, and acetylsalicylic acid has an Rf value of 0.79. The active chemical ingredient in Anacin was …show more content…

Once with Tylenol, Anacin, acetaminophen and acetylsalicylic acid samples spotted separately and once with the unknown samples co-spotted with the known samples. The goal is to identify the main chemical components in Anacin and Tylenol, either acetaminophen or acetylsalicylic acid. Silica (SiO2) gel will be used as the stationary phase and an ethyl acetate (C4H8O2) containing 0.5% acetic acid (CH3COOH) solution will be used as the mobile phase. The molecular structures of the stationary and mobile phases are shown in Figures 1 and 2. The stationary phase is polar protic and the strongest intermolecular force present is hydrogen bonding. The mobile phase is aprotic, with the strongest intermolecular force being dipole-dipole interaction. While both acetylsalicylic acid and acetaminophen are polar substances and should interact strongly with the polar protic silica, acetaminophen is the more polar of the two (more hydrogen bonding) and as such should interact more strongly with the silica gel than the acetylsalicylic acid. This will result in the faster adsorption and slower desorption of acetaminophen compared to acetylsalicylic acid. Thus the acetaminophen distance traveled (and as a result the calculated Rf value) will be lower than that of acetylsalicylic acid . The molecular structures of acetaminophen and acetylsalicylic acid are shown in Figures 3 and 4. Ultimately, comparing the Rf values of Tylenol …show more content…

This was due to the stronger intermolecular forces between acetaminophen (hydrogen bonding from both the amide and phenol) and the solid stationary phase compared to the weaker intermolecular forces between acetylsalicylic acid (hydrogen bonding from the carboxylic acid) and the solid stationary phase. This resulted in faster desorption and slower resorption of acetaminophen compared to acetylsalicylic acid. Overall, thin layer chromatography is a useful tool for determining unknown chemical components in a substance. Conclusion The purpose of this experiment was to determine the active chemical component in Tylenol and Anacin using thin layer chromatography. The active chemical ingredient in Tylenol was determined to be acetaminophen while the active chemical ingredient in Anacin was determined to be acetylsalicylic acid. Works Cited Gupta, H. (2016). [Silica Gel Structure]. Retrieved September 23, 2016, from http://www.biologydiscussion.com/micro-biology/chromatography/thin-layer-chromatography-with-diagram/18037 Thin Layer Chromatography Lab Package [PDF]. (2016). Tempe: Arizona State

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