Preparing your own thin layer chromatography plates (and then using them)

Step 3 Weigh out and mix the silica gel and plaster of paris

The plaster of paris is the binder and is present only to keep the silica from sloughing off the glass slides. I have found 10-20% (by weight) plaster of paris in the final mix works well.

For this project, weigh out:

• 1.0g plaster of paris
• 4.0g silica gel (ground)

Combine these in the mortar and pestle and grind together very well. The mixture should be very homogeneous and the finer the particles the better the separation.