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Chemical Ionization Options
Use the AutoLink field to activate the appropriate method for the EI or particular
CI reagent required.
Multiple CI Reagents in the Same Run
In some demanding applications, it may be desirable to change CI reagents
within a single chromatographic acquisition. This is done by time programming
the GC/MS Method so that the correct External Events are opened during the
corresponding MS acquisition time for each CI reagent. In this example, a
GC/MS method named TRI_CI is created to use acetonitrile CI (Event A,
Channel A) for the first ten minutes of the run, then methanol CI (Event B,
Channel B) and methane CI (Event C, Channel C) in the succeeding ten-minute
segments. To develop this method, open the Method Builder and choose to edit
ACN_CI.mth. After opening the method use the menu command
File…Save As
to save the method as TRI_CI.mth.
3800 GC Method Section
Create an External Events program in the GC Sample Delivery section to open
different channels of the MCI Module as desired during the GC/MS run:
Saturn MS Analysis
Similarly, in the Method Directory item 2000 Mass Spec Control…MS Method
Editor, the MS Method is split into time segments. The method is set up first for a
30 minute run using the ACN_CI tune file. Segment 1 is a Filament/Multiplier
delay until solvent front elutes from the GC column. Segment 2 is for acetonitrile
CI acquisition.
