A mass spectrometer is an analytical tool used to measure the molecular mass of a sample. The three fundamental parts of a mass spectrometer are the ionization source, analyzer, and the detector. A mass spectrometer does the following:

• it produces ions from the sample in the ionization source.
• it separates these ions according to their mass-to-charge ratio in the mass analyzer.
• it fragmentizes the selected ions and analyzes the fragments in a second analyzer.
• it detects the ions emerging from the last analyzer and measures their abundance with the detector that converts the ions into electrical signals.
• it processes the signals from the detector that are transmitted to the computer and controls the instrument through feedback.