by
GOM » Thu Aug 20, 2015 11:22 am
Cheers - a silicone sounds good
My thinking about the diatomaceous earth is that its porous structure and thus large surface area (up to 4sqm/g), can take a large silicone loading(10%+).You could also use brick dust.
With a packed density of approx. 0.5g/ml and. say, a 10% silicone loading would give 0.05g silicone per ml
I agree with the thin layer spread - sprinkle over some adhesive tape that can easily be cut up into sections? - perhaps check the diffusion profiles with headspace GC, first for consistency and then with time?
Another option could be to pack a 5mm bed in a short 2cm length of glass/PP (a cut down 2ml syringe) tubing held in place at each end with a frit or glass wool. This would give 2 surfaces for diffusion and perhaps allow air to percolate through
Cheap and cheerful
Ralph
ralph.calvert@gmail.com