How do you separate microcrystalline cellulose from amino acids in a powder mixture?

Question

I am looking to separate out the microcrystalline cellulose that has been mixed in with amino acids in a powder mixture.

I have tried suspending the powder mixture in water and then filtering out the microcrystalline cellulose afterwards. The amino acids in the mixture dissolve cleanly without a trace in water after stirring. Although microcrystalline cellulose is supposed to be insoluble in water, which mostly does form a layer in the solution once the fine particles settle after a while, somehow I find that a slight amount of it seems to gets dissolved as well. Either that or it requires an even finer filter, although I have already tried using a filter of 0.1 micron pore size, which should have been enough to filter out any microcrystalline cellulose particles that are still suspended in the solution, but it seems that some traces still remain after filtering.

I would like to cleanly separate out the microcrystalline cellulose from the amino acids in the mixture. Any suggestions as to how I would be able to do this, such as using water or other solvents, or through other means to separate out the microcrystalline cellulose from the amino acids in the powder mixture?

Answer 1

I would try to use a 5-10 cm layer of fine SiO2 particles above a slow filter in a Buchner funnel. I'd be surprised if it didn't do the trick.

Consider that the cellulose particles you see after filtration could come from the paper filter as well (I sometimes see such tiny tiny particles floating around after filtration), in which case it may help to submerge the filter in a beaker of hot water before use, and in the worst case, carry out the SiO2 filtration AFTER the filter paper (in a column with a fritted disk for instance, above larger sized SiO2 not to waste the fritted glass with tiny particles).