Thermo Scientific TSQ Quantum GC, User Manual

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Functional Description
Mass Spectrometer
Thermo Scientific TSQ Quantum XLS and TSQ Quantum GC User Guide 33
• Mass Analysis
• Collision Cell and CID Efficiency
• Quadrupole Offset Voltage
• Mass Analyzer Lenses
Quadrupole Rod Assemblies
The three rod assemblies used in the mass spectrometer are numbered from the ion source end
of the manifold and are designated Q1, Q2, and Q3. Q1 and Q3 are quadrupoles that enable
high-resolution scans without signal loss.
Q1 and Q3 are square arrays of precision-machined and precision-aligned, hyperbolic-profile
round rods. Q1 or Q3 are shown in
Figure 20 . Quartz spacers act as electrical insulators
between adjacent rods.
Figure 20. Q1 or Q3 quadrupole
Q2 is a square-profile quadrupole rod assembly. Q2 always acts as an ion transmission device.
The Q2 quadrupole rods are bent through a 90-degree arc. In addition to reducing the
footprint of the instrument, this prevents the transmission of unwanted neutral species to the
detector and dramatically lowers the noise level in the data. Q2 has become synonymous with
the term
collision cell . Technically, the collision cell is the chamber that encloses Q2 where
collision-induced dissociation can take place if the argon collision gas is present. See
Figure 21 .