Mass Analyzer · 2 / 3
Ions spiral around a central spindle in a purely electrostatic field
The Orbitrap uses no magnet — only a static electric field. Ions are injected around a central spindle electrode and follow a spring-like spiral: orbiting the axis while also oscillating back and forth along it. Crucially, the axial oscillation frequency depends only on m/z, and that is what is measured.
Watch the full cycle: ions are injected from the left and spiral around the spindle (top), their axial oscillations build up the mass spectrum (bottom), then the signal fades as the measurement ends.
Like FT-ICR, the Orbitrap measures ions non-destructively: the orbiting ions induce an image current, which is Fourier-transformed into a spectrum. It delivers very high resolution and mass accuracy in a compact, magnet-free package.