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3
CI Troubleshooting
Signal-Related Symptoms
This section describes symptoms related to the signal. The symptom may be
too much signal, too little signal, a noisy signal, or an incorrect signal.
Signal-related symptoms are generally observed during tuning but may also be
observed during data acquisition.
Error messages in autotune due to insufficient signal may vary. The following
symptoms are covered in more detail in this section:
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No peaks
When troubleshooting "no peaks", it is important to specify what mode of
operation is being used and what expected peaks are not being seen. Always
start with methane PCI and verify presence of reagent ions.
No reagent gas peaks in PCI
If MS has been working well and nothing seems to have been changed
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58
No peaks. See
page
58.
No or low reagent gas signal. See
No or low PFDTD signal. See
Excessive noise. See
page
Low signal-to-noise ratio. See
Peak at m/z 32. See
page
Wrong tune file loaded, or tune file corrupted
Wrong ion polarity (there are no reagent ions visible in NCI)
No reagent gas flow; look for background ions and check pressure
Wrong reagent gas selected for the tune file (looking for wrong ions)
Large air leak
Dirty ion source
Poor vacuum (pump problem). See
7250 Accurate-Mass Q-TOF Troubleshooting and Maintenance Manual
page
60.
page
61.
62.
page
62.
63.
page
56.
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Table of Contents
Troubleshooting
