Lab Report Column Chromatography

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• The retardation factor or Rf value is the ratio of the distance the compound travels to the distance the solvent travels. The Rf value allows the experimenters to determine if the compound is polar or nonpolar. If the compound is nonpolar (the Rf value is close to 1), then it will have a little to no affinity in the stationary phase. If the compound is polar (the Rf value is close to 0), then the compound is very polar and has little to no affinity in the mobile phase. These determinants will help decide which eluent should be selected for the chromatography process. • The filter paper inside the developing column ensures that the chamber is saturated in the vapors of the eluting solvent. It is important to have a cover on the container in order to minimize evaporation of the solvent. The best results will be obtained if the solvent is always fresh. By keeping the solvent fresh, its composition remains consistent during all of the experiments. If the solvent is given time to dry in certain spots, the homogeneity of the column is compromised. • Column chromatography consists of solid-liquid phase partitioning. Several steps are involved in order to perform a separation using this technique. The first step is selecting a column. The size of the sample which will be separated or purified will indicate what size the column should be. The difference in Rf values is also a…show more content…
If the components were not successfully separated from the unknown, then there is a possibility that the incorrect solvent was chosen as a mobile phase. The eluting solvent might have been too strong and immediately eluted all the compounds. Polar compounds have a low affinity to non-polar solvents so a non-polar solvent should be introduced in order to try and preserve some of the compound to
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