A mass spectrometer is used to:
- Identify the presence of isotopes.
- Measure the relative abundances of isotopes.
- Measure relative atomic masses and relative molecular masses.
- Identify unknown compounds.
Five stages of the spectrometer
- Vaporisation. The sample is injected as a gas, or as a liquid that is heated to vaporise it.
- Ionisation. An electron gun forms positive ions by bombarding the atoms with high-energy electrons which knock electrons off.
- Acceleration. The positive ions produces pass between a series of negatively charged plates. These plates accelerate these positive ions to high speeds.
- Separation. An electromagnet deflects ions towards the detector. The lighter ions are deflected the most.
- Detection. The detector responds to the ions that hit it and produces a signal that corresponds to the number of ions. A computer converts both measurements into a spectrum on a paper recorder. The series of peaks is called a mass spectrum.