[Planxguy]

Question for thin layer chromatography

   Solvent system is: 3:1:1

Butan 1 ol:Glacial acetic acid:water

Would you expect amino acids with polar or non-polar side chains to move further
        due to partition chromatography alone in the solvent system of this experiment?

[Arkcon]

You can solve this one for yourself, and we encourage people on these boards to do just that.  You have to compare the polarity of the stationary phase (that which is coated on the TLC plate), and the polarity of your mobile phase, to determine which will travel farther.  Any thoughts?

[Planxguy]

Thank you for your reply.

I do understand that polar molecules will be retarded by the polar (silica) stationary phase. And non polar compounds will travel further with a less polar solvent.

But what I do not understand is, is my solvent system non polar? polar? or less polar?

and also by partition chromatography does it mean to exclude the stationary silica gel?

[MOTOBALL]

My understanding is that partition chromatography is, for example, paper chromatography in which the analyte is partitioned between the developing, mobile phase and the water (naturally present from the atmosphere) in the cellulose matrix.  The cellulose (paper) is there only as a physical support for the water.

Silica gel chromatography is adsorption chromatography---the analyte is adsorbed/desorbed onto/from the silica gel repeatedly.

However, I would like to hear what a modern text on chromatography has to say.