3
Troubleshooting
Sensitivity Symptoms
Thermo Scientific
DSQ II Hardware Manual
147
Isotopes are missing or isotope ratios are incorrect.
Possible Solutions
• Masses are not resolved. Adjust resolution and/or ion offset in
DSQ II Tune
by selecting
Tune | Show Manual Tune View
and then click the Resolution tab.
• Detector gain is too low. Increase the detector gain.
Irregular ion ratios.
Possible Solutions
• The wrong type of ion volume is installed. EI and CI require different ion volumes,
which can not be used interchangeably.
• Lens voltages or prefilter offset voltage are incorrect. Select
Restore Default Tune
in
DSQ
II Tune
.
• Prefilter is misaligned or broken. Check the alignment of the prefilter.
• The ion volume, lenses, or prefilter are dirty. Clean the ion volume, lenses, and prefilter,
as described in
“Cleaning the Ion Source, Lenses and Prefilter”
.
• The GC column is not inserted beyond the end of the transfer line or it is broken off in
the ion source. Make sure the column is properly installed.
• There is a large air leak. Run a leak check as part of an automatic tune or look for
m/z
28
as base peak in full scan. See
• Cables are incorrectly installed or missing. If some ions are present, ensure the entrance
lens is properly connected and P1 and P2 cables are connected to the low pass filter
board.
Weak Signal.
Possible Solutions
• The ion volume, lenses, or prefilter are dirty. Clean the ion volume, lenses, and prefilter,
as described in
“Cleaning the Ion Source, Lenses and Prefilter”
.
• The detector gain is set too low. Run detector gain calibration as part of an automatic
tune. Try a higher gain setting. A multiplier >2-3 years old may be too noisy for the
detector gain calibration to accurately set the voltage. Replace multiplier if necessary.
• The wrong type of ion volume is installed. EI and CI require different ion volumes. They
may not be used interchangeably.
Содержание DSQ II
Страница 1: ...DSQ II Hardware Manual 120299 0002 Revision C December 1 2009 ...
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Страница 36: ...1 Basic Operations Shutting Down the GC MS System 20 DSQ II Hardware Manual Thermo Scientific ...
Страница 182: ...4 Vacuum System and Gas Inlets Gas Inlet Components 166 DSQ II Hardware Manual Thermo Scientific ...
Страница 198: ...5 Ion Source and Inlet Valve Inlet Valve Upgrade 182 DSQ II Hardware Manual Thermo Scientific ...
Страница 202: ...6 Prefilter and Quadrupole 186 DSQ II Hardware Manual Thermo Scientific ...
Страница 206: ...7 Ion Detector Electron Multiplier 190 DSQ II Hardware Manual Thermo Scientific ...
Страница 242: ...226 DSQ II Hardware Manual Thermo Scientific Index ...