Fig. 1.

a Schematic diagram of a simple mass spectrometer with source, quadrupole, and detector, sorting ions by m/z. b Generation of a mass spectrum for a pure compound. The molecular ions fragment, and the charged fragments are separated by the quadrupole and quantitated by the detector, yielding a standard mass spectrum. c Mass spectrum of testosterone. d Schematic diagram of a collision cell. Following ionization, molecular ions are accelerated into the collision cell via electrostatic repulsion where they collide with gas molecules in the collision cell through a process called collision induced dissociation (CID). CID imparts internal energy to the molecular ion, which induces fragmentation