Fragmentation reactions of Cu + ‐cationated α‐amino acids

The Cu + ‐cationated species of 12 α‐amino acids have been prepared by fast‐atom bombardment and the unimolecular (metastable ion) fragmentation reactions have been examined by tandem mass spectrometry. The major unimolecular fragmentation reactions observed involve elimination of H 2 O, elimination of CO 2 and elimination of CH 2 O 2 . In addition, for Cu + ‐cationated asparagine and glutamine, elimination of NH 3 is a significant reaction and for Cu + ‐cationated proline, elimination of H 2 is a major fragmentation reaction. It is concluded that there are three pathways to elimination of (H 2 , C, O 2 ), direct elimination of CH 2 O 2 , direct elimination of (H 2 O+CO) and elimination of (CO 2 +H 2 ).