8CI Maintenance
General Information
206 7000/7010 Series TQ GC/MS Operating Manual
General Information
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 with the tank in an upright position. This will help prevent
liquid ammonia from getting into the flow module.
To set up your MS for CI operation
Setting up your MS for operation in CI mode requires special care to avoid
contamination and air leaks.
Guidelines
• Before venting in EI mode for the installation of the CI source, verify that the
GC/MS system is performing correctly.
• Ensure the reagent gas inlet line(s) are equipped with gas purifiers (not
applicable for ammonia).
• Use extra-high purity reagent gases; 99.99% or better for methane and as
pure as is available for other reagent gases.
Always perform any maintenance procedures using hazardous solvents under
a fume hood. Operate the MS in a well-ventilated room.
To Next Page
Loading...
Need help?
General
