Chromatography Forum

I am using silver in some peptide couplings in dmso. I have used dithiothreitol in an effort to chelate the silver ions for removal, but the complex seems soluble in dmso and i have found that a significant amount of silver has reduced in the guard column, turning the silica black. I cannot imagine that this is a good thing. I was wondering if there were any better way to remove the silver ions prior to purification?

I do not know if AgCl is soluble in DMSO so you can try to remove DMSO by by liophylization, then add HCl solution to your peptide and remove AgCl by centrifugation.

The precipitate may be very fine, making it difficult to remove - use of a sulfate ion exchange resin may trap the silver - as long as it does not adsorb your peptide. (You should not have to make a column, just mix and separate.)