Thin Layer Chromatography Essay

In this investigation, a TLC plate and ethyl acetate (solvent) were used to measure the Rf values of four different solutions of Tylenol, Anacin, Acetaminophen, and Acetylsalicylic acid. The value of Rf depends on the strength of the intermolecular forces that exists in molecules. The stronger the intermolecular forces are, the harder the solvent moves the molecule up, resulting a small Rf value. In contrast, molecules with weak intermolecular forces tend to have a high Rf value.

The unknown sample was identified to contain Acetaminophen, Aspirin, and caffeine based on comparison of known Rf values (Table 1). When comparing the traveled UV lit spots (figure 1), Aspirin and Ibuprofen traveled the same distance from the start line. Unknown sample 16 contains Aspirin not Ibuprofen, due to the intensity of the spot under UV light. Aspirin and the unknown shared that same intensity, whereas Ibuprofen did not share that same strength of brightness. The distance traveled by the samples was dependent upon their affinity for the mobile phase 200:1 ethyl acetate – acetic acid. The samples that traveled the furthest like the Aspirin and Ibuprofen were the most soluble in the mobile phase. The samples that traveled the shortest

2. The TLC results showed two different spots that traveled different distances on the TLC plate, one for ethyl vanillin and one for ethyl vanillin alcohol which proves there is no evidence of the starting material in our final product. The product (ethyl vanillin alcohol) was more polar and interacted more with the solvent than our starting material (ethyl vanillin). This increase in polarity is due to the extra alcohol group in the ethyl vanillin alcohol and the smaller Rf value also indicates it is more polar and pure than the ethyl vanillin.

The GC data for the product produced graph with a signal level out-of-range in peak. This gave a retention time 2.952 minutes. This would not indicate any of the possible ester products. However, after appropriate dilution, a retention time of 1.753 minutes was obtained. This retention time indicates that the ester product was ethyl benzoate.

In the first part, there may have been cross contamination of materials, especially since periods before us had already performed the experiment. During chromatography, our spot sizes were initially very varied, as we didn’t know exactly how much of each substance to place when we began. Thus, the substances in more abundance would have greater opportunity to travel up with the eluent, skewing the results. In the beginning, we even put 6-7 drops, causing some of the substances to mix together. Touching the TLC plate may also have disrupted some of the substances traveling up.

Organic Compounds contain Carbon, a versatile bonding element due to its ability to form four stable bonds. They can be separated from mixtures and identified through Thin Layer Chromatography (TLC). TLC is a simple, and rapid analytical technique that provides qualitative information about a sample. It is based on the principle that different compounds will have different attractions to the stationary and mobile phases. Typically, already characterized compounds can be identified chemically.

Howlett, S. E. and Steiner, R. R. 2011. Validation of Thin Layer Chromatography with AccuTOF-DART™ Detection for Forensic Drug Analysis*. Forensic Sciences [e-journal] 56 (5), pp. 1261--1267. Available through: Anglia Ruskin University Library website http://libweb.anglia.ac.uk [Accessed on 11 March 2014].

The yellow band, ferrocene, elute from the column with the like non-polar phases of hexanes. Theoretically speaking an additional orange band, representing acetylferrocene, should have eluted after the shift in mobile phases. Considering that the mobile phase changes from a non-polar content to that of higher polarity with the addition of ethyl acetate, it is logical that a polar species like acetylferrocene would elute. After collecting and evaporating the solvent portion of the darkest yellow fraction, the resulting mass was 0.017 g, an 18% yield from the starting the amount. This yield could be raise if the additional yellow fractions were collect. The melting point of this collected fraction was 170°C, which reasonably close to the literature value of 172. Considering that the species sampled was the started reactant, thus there was no chemical change, it safe to assume the purified product is

Introduction The purpose of this experiment is to analyze the following analgesics: acetaminophen, aspirin, caffeine, and ibuprofen. This analyzes is to be done using thin layer chromatography (TLC). Also, in this experiment we isolate β-carotene from spinach using column chromatography (CC). Chromatography is a separation technique. It separates a mixture in one state of matter by moving it through another substance in another state of matter (Woodford, 2016).

Whereas, hexane is non-polar because it contains only single bonds of hydrogen and carbon and the difference between the electronegativity of carbon and hydrogen is very small. Ferrocene is less polar than acetylferrocene and hexane is less polar than ethyl acetate so using the property of "like attracts like" ferrocene will have a greater affinity to hexane and acetylferrocene will have a greater affinity to ethyl acetate. Thus, ferrocene had to be eluted with hexane as it would bind to it and flow out and acetylferrocene had to be eluted with ethyl acetate as it would bind more to ethyl acetate than the adsorbent (silica) and flow out later. Table of Chemicals Compound Structure Physical Appearance Melting Point/ boiling point Safety Hazards Ferrocene Orange-

TLC Analysis of Analgesic Drugs Author: Monique Amanda Mendez Lab Instructor: Wenmo Sun Organic Chemistry Lab 243A: Section 038 Date Work Performed: 02 September 2015 Discussion: Lab 1a - TLC Analysis of Analgesic Drugs Discuss the relative polarities of the components of the analgesic drugs based on their functional groups The relative polarity of the analgesic drugs depends on their functional groups. Polarity of the drugs depends on several differentiating factors which include how the compound can hydrogen bond to itself or another compound, the number of electronegative atoms that are present within the structure of the compound, the net dipole moment of the molecule and the polarizability of the bonds or atoms that are present within the compound, which can highly define how polarizable the compound is or will be. The more polar the functional group, the stronger the bond is to the stationary phase, making it slower for the molecules to move down the TLC plate, thus the stronger it will be absorbed on the surface of the solid phase.

Introduction Chromatography is an experimental technique used to separate a substance into its components based upon their polarities or non-polarities. The purpose of this experiment was to use thin layer chromatography to separate lipid molecules in an egg yolk sample. Silica thin layer chromatography (TLC) plates were used along with the egg yolk sample and standard solutions of the three lipids that were extracted from the egg yolk. Very small portions of the analytes were added to the plate and placed into the chromatography chamber, which was filled with a solution of chloroform, methanol, and water. The egg yolk separated into its components, and the standard solutions also moved according to polarities.

To conclude, it is evident from the Rf values obtained that unknown # 3 Rf is closest to that of 2 – Octanone. With a 7.2 % error, this can be due to the reagent being diluted with too much ethanol or still containing traces of the acid, however if traces of the acid are present then the melting point[3] should be significantly lower.

The purpose is to develop an initial hypothesis after first run of TLC experiment of the unknown. The unknown solvent is used to indicate the component in the unknown. The unknown solvent was tested with 5 standards: aspirin, acetaminophen, ibuprofen, salicylamide, and caffeine absorbed the solvent of 200:1 solution of ethyl acetate. Based on the observation and calculate the retention factor for each standard to determine the possible components contain in the unknown.

The caffeine separation is easily achieved using HPLC. Liquid chromatography can be divided into different types, including normal-phase, reversed-phase and ion exchange. Reversed-phase partition chromatography uses a non-polar organic coating on a silica structure for the stationary phase. The non-polar coating is commonly formed by the reaction of an organochlorosilane with the OH groups on the silica surface. With normal-phase HPLC, the most regularly used solvents are hexane, isopropanol or THF, while a more polar mobile phase such as methanol/water or acetonitrile/water is usually used for reversed-phase partition chromatography.