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Unformatted text preview: Separation of Dyes, Inks and 1,2-Cyclohexanediol Diastereomers by Column and Thin Layer Chromatography Mark Gumapas September 20, 2007 Methods and Background The purpose of this experiment is to successfully perform three chromatography systems. First, create a column chromatography on a mixture of methyl orange and methylene blue. Second, create a Thin Layer Chromatography (TLC) on different colored pen inks, and another TLC on the diastereomers of 1,2-Cyclohexanediol, cis-1,2- Cyclohexanediol and trans-1,2-cyclohexanediol. Column chromatography is used to separate a mixture of two or more compounds. In this case, it is used to separate a mixture of methyl orange and methylene blue. The difference in polarity between the two parts is what is being used to separate the different components. In the process of column chromatography there is a liquid mobile phase that gets flowed over the stationary phase and the compound. More polar compounds are likely to be attracted to other polar compounds and vice versa. In column chromatography, the length of time spent in the stationary phase depends on the polarity of the solvent and the compounds, and the polarity of the stationary phase (silica gel). More polar compounds have a greater affinity for the stationary phase, making their retention time longer than less polar compounds. To complete the separation of the two different colored dyes, a combination of solvents is required to elute each compound depending on the resulting polarities of each. In addition to column chromatography, thin layer chromatography also has a stationary phase and a mobile phase. However, the amounts and samples of each are much smaller than column chromatography. In organic chemistry, TLC is a quick way of analyzing the progress of a reaction. Here the mobile phase is not flowed over the compound and stationary phase, but instead placed below the stationary phase and allowed to rise via capillary action. In the case of TLC, the stationary phase is a thin layer of absorbent material, and a small amount of the solution to be separated is put on the absorbent. When the absorbent takes in the mobile phase, the separation occurs as more of the absorbent takes in the mobile phase. In this experiment, TLC was used to separate black, blue, green, and red Vis-à-vis pens to see the colors that comprise them....
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