Your copper peptide product should be this exact blue. If it isn't, you already have your answer. GHK Cu is blue because of coordination chemistry, not dye. The Cu ion at the center Copperbiomolecule complexes in the gas phase. The ternary way Tureek 2007 Mass Spectrometry Reviews Wiley Online Library Theoretical study of copper binding to GHK peptide ScienceDirect China Copper Peptide(GHK Cu) CAS:89030 95 5 Manufacturers Free Sample Alfa Chemical