removal of ag+ before hplc purification

[rtho5616]

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?

[dorota]

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.

[Don_Hilton]

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.)