I have a question on thin layer chromatography (TLC).

Question

My mobile phase (i.e. developing solvent) is a mixture of 2 non-polar solvents.
After preparing the mobile phase, is it necessary to pour some into the developing chamber to saturate the chamber or should we only pour the mobile phase into the chamber just before we place the TLC plate in?

Answer 1

I tend to put the mixture in the developing chamber a while before I run the TLCs. Not too important if all you are doing is looking for the disappearance of starting materials/appearance of product.

Getting the chamber saturated can be important with prep-TLCs where you want an even separation across a wide solvent front.