Chem_Lab_Report_1

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CHM 2204L Exp.1 Thin Layer Chromatography May 19, 2017 Nicholas Tyndall Lab Partners: Abhi Ahuja TA: Darren Turner Professor: Dr. Chandrasekhar Abstract This lab was completed to find the mixture of painkillers in two unknown painkillers. This was done by following the steps were given. The painkillers were mixed with Ethanol and put on to TLC Slides to get R f values, with the values it is possible to figure out what the painkillers are mixtures of. The results mean that unknown painkillers were mixtures of Aspirin, Caffeine or Acetaminophen. The importance of the experiment The objective of this experiment was to find what Painkiller A and Painkiller B were mixtures of and if they included Aspirin, Caffeine or Acetaminophen. Using

Thin Layer Chromatography (TLC), Unknown A and B were compared to the three controlled samples above to see if A or B contained any of the three and if they did which of the three samples. All the samples are put on to TLC Slides after the crushed-up pills were mixed with ethanol and put in a solvent that allows the mixtures to separate and give the results once put under a low wave UV light so that you can see the spots because the liquids are transparent. Experimental The equipment, methods, and procedures used can be found in the lab manual. 1 Methods that are different than the ones provided in the lab manual would be switching step 8 to step 2, and in step 8, the developer was already premade and given. As well as in step 3 the tablets were already crushed into a fine powder. Results The results that were acquired were from Figure 1, all the results have been tabulated and can be seen in Table 1, as well as there is an example of a sample calculation from the table in the Appendix Figure 1. TLC of Painkillers 1 Chandrasekhar. Experiment 1. Thin Layer Chromatography . (2017) 2

Table 1. TLC of Painkillers Samples d (cm) D (cm) R f = d/D Aspirin 4.2 5.0 0.84 Acetaminophe n 3.7 5.0 0.74 Caffeine 2.3 5.0 0.46 Unknown A Spot 1 2.1 5.0 0.42 Spot 2 3.5 5.0 0.70 Spot 3 3.9 5.0 0.78 Unknown B Spot 1 1.4 5.0 0.28 Spot 2 2.0 5.0 0.40 Spot 3 4.1 5.0 0.82 Discussion Painkillers that were known were all pure substances, this is shown in Figure 1, how each of the first three only have one dot visible. The two unknowns were mixtures and this is seen also in Figure 1 how there are multiple dots in each of their rows. To get a rough estimate of what they were a mixture of visualize which dots of the first three samples are at the same height as the unknown’s dots. By doing this you can see that Painkiller A includes similar substance to the first three samples those being Aspirin, Caffeine or Acetaminophen. Painkiller B includes samples similar to Aspirin and Caffeine. To be more accurate solve for R f of the dot, once this is done there are more precise results showing that the estimate above is correct. Also, the substance that was the most polar would travel up the farthest up the TLC Slide due to the slide and the developer being polar. This means that from least to most polar is Caffeine, Acetaminophen, Aspirin As seen in the table and the figure, the first and lowest spot for Unknown B was caused by an impurity in the medicine causing an extra spot to appear where it should not have. The reading stated that chromatography is a technique used to separate mixtures of 3

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chemical compounds in order to identify their component. 2 This is true here it separate Unknown A and B, and was able to identify which of the other samples they had in them by comparing the spots on the TLC Slide. Conclusion The results should what was believed the Unknown A and B included samples of Aspirin, Caffeine or Acetaminophen. The objectives of the experiment were meet by learning what was in each of the unknown samples. This method could be used to determine what is mixed into other unknown medicines. Appendix R f – Retention factor d – Distance traveled by the substance D- Distance traveled by the solvent R f = d/D Sample Calculation 4.2(g)/ 5.0(g) = 0.84 References Chandrasekhar. Experiment 1. Thin Layer Chromatography . (2017) Dragojlovic, An Illustrated Guide to Organic Chemistry Laboratory Techniques. (2008) 2 Dragojlovic, An Illustrated Guide to Organic Chemistry Laboratory Techniques. (2008) 4