A Chromatographic Example

A Chromatographic Example



A sample contains three components (A, B and C). A has a strong affinity for the paper, B for water. C has some affinity for both water and the paper. Four spots (pure A, pure B, pure C and the mixture of all three) are made on a piece of chromatography paper (the stationary phase) and the paper put into a beaker containing water (the mobile phase). After developing, the chromatogram is obtained.



Note that because A had a strong affinity for the paper, it did not move very far up the paper. B, because of its strong affinity for the water, moved up a significant distance. C, with an affinity for each phase, moved an intermediate distance.



We can further observe that our mixture of A, B, and C did indeed contain at least some of each component because there is a spot corresponding to each of the individual components. If one of these spots was missing, we would know that the mixture does not have that particular component.


Continue to read about retention factors.


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