6
Operating in CI Mode
To Perform a CI Autotune
142
7000/7010 Series TQ GC/MS Operating Manual
To Perform a CI Autotune
If you are switching from an EI to a CI source, do not use this procedure. See
Pumpdown and Switch from EI to CI Mode”
Procedure
1
Verify that the MS performs correctly in EI mode first.
2
Click the
MS Tune
icon in the
Instrument Control
panel to display the
Triple
Quadrupole MS Tune
window.
3
If necessary, load a new tune file by clicking on the
Files and Report
tab, then
click
Load
in the
Tune File
area. Select a tune file and click
OK
.
The tune file must match the type of ion source in the analyzer. For a
CI source, select a tune file created for a positive or negative CI source.
4
Click the
Autotune
tab, and select
PCI source
for a positive CI source or
NCI
source
for a negative CI source.
5
Click on
Methane
if you are using methane as the reagent gas, or click on
Ammonia
if using the gas attached to the reagent gas controllers B port as
the reagent gas.
6
If a log file and associated data files of the tune are required, click the
Files
and Reports
tab, and in the
Log Files
section, click
Browse
to create a
directory and files for the logs. Click on the required log and data files check
boxes.
7
Click on the
Manual Tune
tab, and select the I
on source
tab. In the
CI Reagent
Gas
section, select
CI Gas A
or
CI Gas B
as the reagent gas, and then enter a
CI Gas Flow
rate of 20% for a PCI source or 40% for an NCI source. Click on
the
Autotune
tab to return to Autotune.
CAUTION
Always verify MS performance in EI before switching to CI operation.
CAUTION
Avoid tuning more often than is absolutely necessary; this will minimize PFDTD
background noise, and help prevent ion source contamination.