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Ion Transmission and Mass Analysis
Mass Analyzers
Thermo Scientific Orbitrap Fusion Series Hardware Manual 35
Quadrupole Mass Analyzer
The quadrupole mass analyzer (Q1) transmits ions from the MP0 ion guide. This mass
analyzer includes quadrupole Q1, lens L2, and the dual-split gate lens. For the location of
these components, see Figure 13.
Quadrupole Q1 is a square array of circular rods (Figure 22). Quartz spacers act as electrical
insulators between adjacent rods. The mass spectrometer applies an RF voltage to the rods,
generating an electric field that guides the ions along the axis of the quadrupole. The mass
spectrometer applies the DC quadrupole offset voltage to the quadrupole rods in addition to
the resolving DC voltage. The offset voltage accelerates (or decelerates) ions and, therefore,
sets the TKE of the ions as they enter the quadrupole rod assembly.
Figure 22. Quadrupole Q1 (side and end views, Orbitrap Fusion and Orbitrap Fusion Lumos MSs)
The lens L2 is a metal disk with a small hole in the center through which the ion beam passes.
Lens L2 focuses the ions coming from the quadrupole into the MP1 ion optics.
The dual-split gate lens (Figure 23) starts and stops the injection of ions into the multipole
MP1 by deflecting the beam at high speeds at the appropriate times. The voltages on the
dual-split gate lens depend on the calibration of the system. The voltage to deflect the beam is
typically 50 Vdc.
Figure 23. Dual-split gate lens (both sides)
Orbitrap Fusion MS
Orbitrap Fusion Lumos MS
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