From: Analytical model of peptide mass cluster centres with applications
Atom
monoisotopic
nominal
mass defect
1
H
1.00782
0.00782
2
C
12.00000
12
0.00000
3
N
14.003074
14
0.003074
4
0
15.99491
16
-0.00032
5
S
31.97207
32
-0.00087