How long can I store my peptide when it is in solution?

It is not recommended to keep excess peptides in solution. The shelf life of peptides in solution is very limited, especially for sequences containing cysteine, methionine, tryptophan, asparagine, glutamine, and N-terminal glutamic acid. In general, aliquot the necessary amounts of peptide for a few days and relyophilize remaining portions for long term storage if necessary.