Question

How can you tell which mobile phase is more polar in TLC? (hexane/ethyl acetate/ethanol vs. isopropanol/ammonia)? the hexane/ethyl acetate/ethanol travelled up the TLC faster, does this make it more polar?

Answer 1

What's the substrate on the TLC? SiO2? If so that is polar and it should hold the more polar components back (travel slower). My best intuition thinks that ammonia would be more polar than ethanol.

Answer 2

the TLC is silica gel

Answer 3

Since the substrate is silica gel (SiO2), that is a polar substrate and the more polar solvent should move slower than the less polar solvent.

Answer 4

thank you!