+Most elements have more than one stable isotope.
For
example, most carbon atoms have a mass of 12 Da, but in nature, 1.1% of C atoms
have an extra neutron, making their mass 13 Da.
+Why do we care?
Mass
spectrometers can “see” isotope peaks if their resolution is high enough.
If an
MS instrument has resolution high enough to resolve these isotopes, better mass
accuracy is achieved.