Sciencemadness Discussion Board

Powdered Silica gel for liquid chromatography

RogueRose - 30-6-2018 at 22:09

I am going to try my first experiment with TLC and liquid chromatography, possibly with a little pressure. I'm not super concerned about getting lab quality separation for my trial tests and I don't have any powdered silica gel.

I do have a lot of silica gel from desiccant packs (maybe 10KG) and at least 10lbs of cat litter silica gel.

Would grinding either of these into a powder and then using different sieves to get the desired mesh (IDK what size is recommended). I plan on using various alcohols and commonly available solvents for the solvent.

I've watched and read a number of pages and videos on LC and not once did they mention whether the silica can be re-used. Is it possible to wash it well and re-use, especially if running the same material through?

I'm a little nervous about trying LC but it seems like a good step in learning how separate various compounds and I would eventually like to try GC but don't know if that can be used for separating larger amounts like 50-200g of material at a time.

wg48 - 30-6-2018 at 23:40

Quote: Originally posted by RogueRose  
I am going to try my first experiment with TLC and liquid chromatography, possibly with a little pressure. I'm not super concerned about getting lab quality separation for my trial tests and I don't have any powdered silica gel.

I do have a lot of silica gel from desiccant packs (maybe 10KG) and at least 10lbs of cat litter silica gel.

Would grinding either of these into a powder and then using different sieves to get the desired mesh (IDK what size is recommended). I plan on using various alcohols and commonly available solvents for the solvent.

I've watched and read a number of pages and videos on LC and not once did they mention whether the silica can be re-used. Is it possible to wash it well and re-use, especially if running the same material through?

I'm a little nervous about trying LC but it seems like a good step in learning how separate various compounds and I would eventually like to try GC but don't know if that can be used for separating larger amounts like 50-200g of material at a time.

I have considered silica gel too. Specifically cat litter. It can be ground up in a blender very effectively. Apparently the size distribution of the particles is important for sharp spots/peaks I don’t know how effective sieving will be in producing a narrow size distribution.

Perhaps tumbling the powdered silica gel before and or after sieving will round off the particles for more regular packing.

I have also considered how easily the thermal conductivity detectors of GC can be DIYed. Two resistors and two miniature filament bulbs could be wired up in a bridge configuration with a bridge sensor chip and an Ardunio. The glass envelops of bulbs would have to be removed or two holes drilled in the envelope to enable gas flow.
Of cause the column, three temperature controlled ovens, gas regulated and various plumping parts and valves would be also needed, a serous project.

However trying to get the thermal conductivity sensor working would be interesting on its own and can be used for measuring pressure and gas flow.

I would think GC can only be used for mg or less quantities of compounds if it’s a capillary column.