Introduction 1
Troubleshooting and Maintenance Manual 11
Vacuum gauge
The 7200 Q-TOF GC/MS is equipped with four ion vacuum gauges:
• RIS vacuum chamber
• Vacuum manifold chamber
• TOF vacuum manifold chamber
• Turbomolecular vacuum pumps exhaust
The MassHunter Workstation can be used to read the pressure (high vacuum)
in the vacuum manifold, at the turbomolecular vacuum pump discharge, and
the flight tube.
Ionization modes
The G3851BA 7200 Accurate-Mass Q-TOF GC/MS comes standard with both an
EI and CI removable ion source (RIS).
A methane/isobutane gas purifier is provided and is required. It removes
oxygen, water, hydrocarbons, and sulfur compounds.
The MS CI system has been optimized to achieve the relatively high source
pressure required for CI while still maintaining high vacuum in the collision
cell, quadrupole, and TOF tube. Special seals along the flow path of the
reagent gas and very small openings in the ion source keep the source gases in
the ionization volume long enough for the appropriate reactions to occur.
The interface has special plumbing for reagent gas. A retractable insulating
seal fits onto the tip of the interface and is used for both EI and CI.
Switching back and forth between CI and EI sources takes less than 30
minutes with the new removable ion source. The RIS allows the instrument to
remain close to pressure, and provides a cooling chamber with N2 purge for
rapid source cooling without venting the machine. This saves hours in cycle
time over the traditional unit.
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