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Ion Transmission and Mass Analysis
Mass Analyzers
34 Orbitrap Fusion Series Hardware Manual Thermo Scientific
MP3 Ion Optics
The MP3 ion optics transmit ions from the IRM to the dual-pressure LIT. The MP3 ion
optics include multipole MP3 and the transfer lens TL1, which is also known as the front
lens. For the location of these components, see Figure 13.
Multipole MP3 is an array of circular rods that act as an ion transmission device (Figure 18).
The mass spectrometer applies an RF voltage to the rods, generating an electric field that
guides the ions along the axis of the multipole. The transfer lens TL1 focuses the ions as they
enter the LIT.
Figure 21. Multipole MP3
DC Offset Voltages
The mass spectrometer controls the ion transmission through the ion optics by applying DC
offset voltages to each of the ion optics. The DC voltage, offset from the system ground
(defined at the C-trap), increases the translational kinetic energy (TKE) of the ions emerging
from each of the exit lenses through the ion optic path. Increasing the offset voltage increases
the TKE of the ions. The voltages (for positive ions) go from more positive to more negative
as you move from the API source to the mass analyzers.
Mass Analyzers
This section describes the components of the three mass analyzers, voltages applied to the
mass analyzer electrodes, helium damping gas in the mass analyzer cavity, and mass analyzer
operation during mass analysis. Ion manipulation and mass analysis occur in a mass analyzer.
The Orbitrap Fusion Series MS can provide multiple levels of mass analysis. Each level of
mass analysis adds a new dimension of specificity for unequivocal compound identification.
The Orbitrap Fusion Series MS contains the following mass analyzers:
• Quadrupole Mass Analyzer
• Orbitrap Mass Analyzer
• Linear Ion Trap Mass Analyzer
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