Thermo Scientific TSQ Quantum XLS, Руководство пользователя

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2
Functional Description
Mass Spectrometer
32 TSQ Quantum XLS Series User Guide Thermo Scientific
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 22 .
Figure 22. Collision cell, Q2 quadrupole, and lenses
Rf and dc Fields Applied to the Quadrupoles
In a quadrupole rod assembly, because rods opposite each other in the array connect
electrically, you can consider the four rods as two pairs of two rods each. Ac and dc voltages
are applied to the rods and these voltages are ramped during the scan. Voltages of the same
amplitude and sign are applied to the rods of each pair. However, the voltages applied to the
different rod pairs are equal in amplitude but opposite in sign. See
Figure 23 .
Lenses L21, L22,
and L23 Lenses L31, L32,
and L33