Easiest Way to do this Seperation - Uracil from a small Peptide (Aug/30/2007 )

After a reaction, I will have a small peptide and excess free uracil in solution. I need ALL, and I mean nearly ALL The uracil gone. What is the easiest way to do this?

Gel?

A way to precip the uracil w/o harming the peptide? Or rather precip the peptide?

Reacting the uracil with something?

A type of chromatography?

I am really new at this, so thanks.

1. Ultratiltration on membrane with proper MWCO.

OR

2. SPE (solid phase extration) with C18 column/cartridge. (As good as I remember uracil is not retained by C18 HPLC columns - it should be same for SPE column/cartridge.)

thanks!