[scar]

I developed four 5x10cm plates in the same chamber overnight using using about 8 mL of 1:1 methanol/chloroform (pre-washing).  The next day the chamber was dry, and then I baked the plates at approx. 100C for 30 minutes.  After allowing them to cool for a bit, i stored all four plates in a dry developing chamber for about 1.5 weeks before using.  Attached is a picture of some results showing lots of problems, including flakey sides, lots of contaminants, bubbling, and non-uniform application of the detection fluid or non-uniform drying or something.

Compare with these results obtained when the plates were newer (approx. 4 months ago)

I'm not sure why my plates are acting like this.. is it the way I'm prewashing and activating and storing them?
  Did I not wash with enough solvent?  wait too long before using?  Supposed to wait to activate until I am ready to use, or should pre-wash and activate right before use?  Is a dry chamber not suitable for 1.5 weeks storage?  What about long-term storage of the non-washed/non-activated plates? I've just kept them in the original box which is not air-tight or anything....
thank you

[MOTOBALL]

I would look at this plate and say that your chromatography (separation of two major components) is actually better than your original plate, where the two spots are barely resolved.

I think that your treatment of these "bad" plates has resulted in the uptake of some water vapour from the atmosphere when you let them cool from 100 deg. C in the open; after heating, they should have been immediately placed in a desiccator over blue silica gel and allowed to cool, if you wanted very active plates.

If this was my project, I would run the plates with MeOH/CH2Cl2 right to top of plate to clean them; then remove plates and allow to air-dry in the open;  maybe use hair dryer on warm setting to blow off the organic solvents (IN A HOOD) to give an opaque white surface; now store the plates overnight in a closed vessel that has a beaker of water inside.  This will give a saturated water atmosphere, and each plate will absorb the same amount of H2O----you will have de-activated the plates and may be able to consistently generate a spot pattern similar to the "bad" plate.