7 General Maintenance
Ion source cleaning
7000/7010 Series TQ GC/MS Operating Manual 151
Ion source cleaning
The main effect of operating the MS in CI mode is the need for more frequent ion
source cleaning. In CI operation, the ion source chamber is subject to more rapid
contamination than in EI operation because of the higher source pressures
required for CI.
Ammonia
Ammonia, used as a reagent gas, increases the need for foreline pump
maintenance. Ammonia causes foreline pump oil to break down more quickly.
Therefore, the oil in the standard foreline vacuum pump must be checked and
replaced more frequently.
Always purge the MS with methane after using ammonia.
Install the ammonia so the tank is in an upright position. This will help prevent
liquid ammonia from getting into the flow module.
Electrostatic discharge
All of the printed circuit boards in the MS contain components that can be
damaged by ESD. Do not handle or touch these boards unless absolutely
necessary. In addition, wires, contacts, and cables can conduct ESD to the
electronics boards to which they are connected. This is especially true of the
When replacing pump fluid, use appropriate chemical-resistant gloves and
safety glasses. Avoid all contact with the fluid.
The optional dry scroll foreline pump may contain significant quantities of
dust. This dust can contain traces of the chemicals analyzed by the mass
spectrometer. When replacing the pump’s tip seal, do NOT use compressed
air to blow out this dust. Using compressed air will contaminate your
laboratory with potentially hazardous dust.
Always perform any maintenance procedures using hazardous solvents under
a fume hood. Operate the MS in a well-ventilated room.
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