[millsware]

I've noticed that the width of the TLC plate seems to make a large difference in my Rf values.  Yesterday I ran a column where my compound with supposedly an Rf of 0.4 raced right through.  After spotting everything on a wide plate and using the same solvent system, the TLC much better reflected what actually happened on the column.  Am I crazy?  Is there an optimal plate width between accurate Rf values and not being wasteful?

[408]

Too thin and you will have edge effects from volatile solvent evaporation if your chamber has not equilibrated.  Make sure your atmosphere has saturated with solvent first and you will reduce this effect.

[millsware]

Thanks,
 I was wondering if this is why it is recommended to put the filter paper in the chamber.

[Enthalpy]

If the oxygen (or some oxygen) from epoxy ring snapped hydrogen atoms, it can result in a cross-linked polymer. This accounts for the number of hydrogen atoms. Whether the compounds could react like that, I won't risk any kind of opinion whatsoever.