Thin layers of Sephadex superfine:

Thin layers of Sephadex superfine gel can be prepared for size exclusion.  It is soaked in water for a few days and then spread on the plate. These are not dried but stored wet. Capillary action through these molecular sieves is much slower, typically of the order of 1 to 2 cm/hour. Therefore, it takes longer period to develop these plates.

The following precautions must be followed when handling TLC plates:

1. The surface of the TLC plates should not be touched. The plates should be handled carefully by holding at the edges so as to avoid any contamination due to sweat.

2. The plates should be cleaned thoroughly so as to remove any extraneous material that might contaminate the adsorbent.

Figure: Apparatus used for preparing TLC plates where the applicator is filled with the slurry of adsorbent and binder in a solvent.