H2N

1
Fragmentation Patterns
y1
z1
mnHn
Rn-1
Rn
O
R1
O
O
...
H2N
C
C
N
C
C
N
C
C
OH
Facile loss of H3PO4 X-P cleavage preferred
ECD
cn-1
Retention of labile modifications No X-P cleavage
IRMPD CID
bn-1
Roepstorff, P. and Fohlman, J. Biomedical Mass
Spectrometry, 11, 601, (1984).