Glass columns and kits for low pressure flash chromatography. The most used adsorbent is silica 60 with particle size 40?63 μm, however, you may also use our ranges of other LC adsorbents and POLYGOPREP silica phases. Particle sizes <25 μm should only be used with very low-viscosity mobile phases, because otherwise flow rates will be very low. These columns are to be packed by the user.