mass spectrometry
use the molecular ion peak from a mass spectrum to determine the molecular mass
use of fragment ions to identify sections of a molecule
molecular ion M+
positive ion formed when a molecule loses an electron
M+1
due to natural abundance of carbon-13
the height of this peak is relative to the peak for the molecular ion, depends on the number of carbon atoms in the molecule
fragmentation
some molecular ions in the mass spectrometer break down into fragments
fragment ions
other peaks in a mass spectrum
what does the simplest fragmentation form
a positively charged fragment ion and a radical
CH3+
15
C2H5+
29
C3H7+
43
C4H9+
57
C5H11+
71
C6H13+
85
stability trend with peak
the more stable the cation, the higher the peak
why do multiple peaks occur in the molecular ion eigon
different halogen isotopes
why will CO not produce a peak of its own
molecule
uncharged
CO drop
28