Experiment 18 Separation by Chromatography

Rf values can range from 0.0 which indicates that the component did not travel at all, to a maximum of 1.0, which indicates that the component traveled to the solvent front, resulting in no or little retention. It is best to determine the solvent characteristics for a good separation prior to determining the Rf. 

Using a cm rule, determine the length of the solvent front. 

Measure the distance that each component traveled, measuring from the middle of the spot to the point of application and determine Rf. 

What conclusions can you make regarding the unknown mixture  

The unknown mixture clearly shows that it was composed of FDC Blue 2 and FDC Yellow 5. Since blue dye mixed with yellow dye gives green dye, the color of the unknown sample, this further supports the conclusion. 

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