Solid phase peptide synthesis: Has anyone encountered their pre-activation solution (amino acid, DIEA, HBTU, HOBt) turning orange or pink upon mixing?

I am doing a solid phase peptide synthesis using Fmoc chemistry and a Rink Amide low loading resin. Recently I have had problems with my preactivation solution (amino acid, HBTU, HOBt, and DIEA)...

01 January 2014 2,439 15 View