sample preparation for IEF - trouble in normalizing protein (Sep/05/2005 )

In my lysis buffer, I got 7M urea, 0.005% bromophenol and most importantly, 60mM DTT. These substances seems turn the BCA substare from green to purple so that I cant normalize the protein sample for IEF.

Anything I can do?

You can eliminate bromophenol blue when preparing lysis buffer.
This is only used as a tracking dye.

After quantitation & before normalization, just a little amount of bromophenol blue in order to visualize the liquid.