Question

Explain molecular ions, fragment ions, isotopic clusters, and base peak in a molecular mass spectrum.

Answer 1

Molecular ions: when sample passes into the ionization chamber of a mass spectrometer, it is bombarded by a stream of electrons, which form positive ions. These ions are known as molecular ions.

Fragment ions: fragmentation is the process of dissociation of energetically unstable molecule ions. These fragments are used to determine the structural information of the molecules.

Isotopic ions:

It is the combination of peaks, which represents ions of the same elemental composition but different isotopic composition.

Base peak:

The base represents the peak of the most abundant ions. Which is also stable ion.