Sciencemadness Discussion Board

Silica gel for food packaging->silica gel for chromatography?

fusso - 31-10-2019 at 09:58

Can I process silica gel for food packaging to a form that can be used for chromatography? (Column chromatography or making my own TLC plates)
I was thinking about dissolving SG in NaOH then reprecipitate as SG using acid. Can this form be used for chromatography?

Dr.Bob - 31-10-2019 at 10:17

Not readily. The stuff in food packets is not even close to what you need for chromatography. The particle and pore sizes are all different. You could try to ppt it from sodium silicate, but the washing and drying process is tough, and you need to be able to at least crudely separate the particle sizes. There are some chemicals you can make at home just fine, but that is a tough one, as if it is not consisent, you will not be able to reproduce anything well.

If you need small amounts, and you are in the US I can help you. I have lots of various glass columns, and a few plastic prepacked ones. And I have some old bits of silia gel that are still fine for most work. I also have some large 200 x200 mm TLC plates that can be cut into smaller ones for use. All are pretty cheap, at least compared to buying them from Fisher/


S.C. Wack - 31-10-2019 at 17:20

Quote: Originally posted by fusso  
Can I process silica gel


IDK, can you? Chemist, chem thyself...then start a thread IMHO. Ground prill could be closer to the real thing than something that the aspiring chromatographer/supplier precipitated theirself. I suspect that the cheap silica gel sold on ebay (coming from the UK) is made that way. (at the very least it must be technical grade) The experimenter may find that there is an unexpected learning curve in making good silica, alumina, and florisil.

PS TLC silica is like 600-1200 mesh. 400-600 is already a chore with mortar and pestle.

[Edited on 1-11-2019 by S.C. Wack]

Ubya - 1-11-2019 at 06:17

and i have been fantasizing of using kitty litter silica gel as stationary phase in column chromatography for 2 years. meh i'll still try

DavidJR - 1-11-2019 at 12:17

If grinding up silica gel, be sure to use appropriate respiratory protection.