MASS SPECTROMETERY AND RELATIVE MASSES OF ATOMS, ISOTOPES AND MOLECULES
A mass spectrometer measures the masses of atoms, molecules and fragments of molecules
Ions are formed (positive ions).
Ions are deflected by a magnetic field according to mass to charge ration (m/z)
It calculates the relative abundance of each positive ions and displays it as a percentage
Sample must be in the gaseous state
The sample is injected in the mass spectrometer where it is vaporized
The vapor is bombarded with high energy electrons.
The electrons collide with the atoms or molecules
One or more electrons are removed from the atoms to form positive ions
The ions formed are accelerated with electric field
The positive ions enter a magnetic field
The ions are deflected based on their mass to charge ratio
Ions with large mass to charge ratio are deflected less
If ions have the same charge, then they are deflected based on their mass
The deflection is inversely proportional to their mass
The deflected ions pass through a narrow slit and are collected on a magnetic plate connected
To an amplifier
The strength of the magnetic field is then changed to detect positive ions with other m/z ratio
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