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Chemical Ionization Options
Setting CI/MS Parameters in the MS Method Editor
To adjust CI reagent flows for a given CI gas and to use the appropriate
parameters in a CI/MS acquisition, you will need to modify the GC/MS Method for
each reagent Channel so that CI/MS parameters for each reagent are
appropriate. Open the Method ChannelA (or its equivalent) that you created in
the
Selecting Reagent Channels in the GC/MS Method
. From the Method
Directory select the entry MS Method Editor under 2000 Mass Spec Control. The
MS Method Editor dialog will appear.
Modify the method to create a single-segment method for CI/Auto acquisition.
You may later use this method as a default method for CI acquisition with the
MCI Module, so you may wish to adjust method parameters such as Start and
End Times and Low and High Mass appropriately for your samples.
NOTE: If you do want to use the method for GC/MS acquisitions, remember to
assure that there is a Filament/Multiplier delay segment with ionization method =
None.
Click on the tab dialog Ionization Mode - CI Auto to choose CI parameters for this
MCI Channel. Parameters for the default CI reagent Methane will be shown.
Click on the selection arrow in the Reagent Gas field and choose the CI reagent
you have selected for Channel A of the MCI Module. In this example we have
chosen acetonitrile for Channel A:
