[emanuel]

I recently did a thin-layer-chromatography lab but I don't really understand the result. I understand the principle - different substances have different tendencies to bind to the mobile phase or the stationary phase. But I don't understand what affects those tendencies it.

The stationary phase was composed of cellulose and the mobile phase composed of 36 cm^3 2-propanol, 9 cm^3 methyl ethyl ketone and 15 cm^3 hydrochloric acid with a concentration of 1,0 mol/dm^3

The result looked like this:

From left to right each dot represents: Lysine, proline, leucine, glycine, alanine, aspartic acid

How does the chemical structure of these amino acids, the stationary phase, and the mobile phase affect the distance traveled by each amino acid?

(Also, does pH play a role? Would changing the concentration of hydrochloric acid affect the outcome?)

[Arkcon]

First of all, nice diagram, you really make the results clear.  So thank you for that.  Now, begin by drawing the structure of each amino acid, and see what adding acid will do to each molecule.  Compare the structures to the distance traveled.  Also, compare the properties of cellulose and the solvent mix you used.

[Babcock_Hall]

I would also keep in mind that the protonation states of the amino acids will be different in this mobile phase than they would be in a cellular environment, which is not far from pH 7.