The analysed objects are ions
The method first creates charged particles, then separates and detects them using electrical, magnetic or related motion-dependent arrangements. Signal position reflects mass-to-charge ratio, so charge state matters alongside mass. Multiply charged and singly charged ions of similar mass need not appear at the same spectral position.
References: [1]
A magnetic-separation model
In one model, crossed electric and magnetic fields select an ion speed before a separate magnetic field bends the trajectory. With appropriate charge and field information, the curvature reveals mass. This arrangement illustrates the physical principle without describing every analyzer used in practical mass spectrometry.
References: [1]
Investigating isotopes
Aston developed mass-spectrographic instruments in 1919 to map isotopes through beam behaviour in electrical and magnetic fields. The method distinguished atoms with similar chemical identities but different masses. An element’s average atomic weight and the separate masses of its isotopes consequently describe different quantities.
References: [2]
Spectra and reference conditions
Chemical identification can compare unknown and reference spectra, but ion sources and instrument settings influence signals. NIST records spectral sources and instrumental information alongside the plots. Peak positions, relative intensities and complementary observations therefore work together to support an identification, rather than operating as context-free labels.