Urea and ion exchange

[Roney Graf]

In article <B0001705182 at spider.cigb.edu.cu>, ricardo.silva at cigb.edu.cu wrote:

> Hi all,
> Several colleagues of mine have advised me against using high 
> concentrations (8 M) of urea in ion exchange runs. In their 
> experience, nothing binds under this conditions. This puzzles me, 
> because being urea an uncharged species, it shouldn't interfere with 
> ion exchange, right?
> Does anybody have similar experiences and/or have an explanation?

   All I can say is that I have seen it done a few years ago, and it
worked - I believe it was on Q-Sepharose and eluted with KCl. One source
of trouble I can think of is to get your eluting salt to dissolve in hi
conc urea. Just 2 cents on this one...

roney