Varian 4000 GCMS, Installation Procedures Manual

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3.4 Air Water Check
From the Checks and Adjustments tab in Manual Control highlight Air/Water
Check and click
Start
(refer to Figure 3.6). Click
Done
when finished. If the m/z
19 to m/z 18 ratio is greater than 50% or the peak width at 10% peak height of
the m/z 28 signal is greater than 1 Dalton, the cause should be investigated
before proceeding with the installation.
NOTE: This air/water check may not give usable results until auto tuning the
system.
Figure 3.6
Air water Check with CI Plumbing
The air and water levels can also be checked with inclusion of the CI plumbing.
From the Checks and Adjustments tab in Manual Control highlight Air/Water
Check, select the CI Plumbing Leak Check box, and click
Start
(refer to Figure
3.7). Click
Done
when finished. The air and water levels can be expected to
increase when the CI plumbing is included.
Air Water Check using Cal Gas Ion Ratios
Another useful monitor of the system’s water level is the intensity of the m/z 197
and m/z 219 signals from the calibration gas FC-43. A high water level will cause
an increase in the m/z 197 signal and a decrease in the m/z 219 signal. As the
water level decreases the intensity of m/z 197 will decrease while the intensity of
m/z 219 will increase.