3
Troubleshooting
Sensitivity Symptoms
Thermo Scientific
DSQ II Hardware Manual
145
• The instrument is out of tune or the tune file is incompatible. Select the correct tune file
for the method or run an automatic tune.
• Ion source board is faulty, which allows the emission current to leak to ground. Replace
the ion source board.
• The magnets above and below the ion source are installed incorrectly. Position both
magnets so the south pole is on top. Electrons will not be focused into the ion volume if
one magnet is upside down.
• The ion source, lenses, or prefilter are dirty. Clean the lenses, and prefilter, ass described
in
“Cleaning the Ion Source, Lenses and Prefilter”
.
• The wrong type of ion volume is installed. EI and CI require different ion volumes. They
may not be used interchangeably.
• Method development problems are occurring. Contact Technical Support or Customer
Support.
• Prefilter is misaligned or broken. Check the alignment of the prefilter.
• Reagent gas is leaking into the analyzer and suppressing the EI signal. Check for the
presence of CI reagent ions in the spectrum. If necessary, replace the CI gas flow module,
as described in
“Replacing the CI Reagent Gas Flow Module”
• Insufficient sample delivery due to clogged syringe needle. Clean or replace the syringe.
• Incorrectly matched syringe, injection port liner, and column depth in injector. See the
GC documentation for compatible combinations.
Sensitivity is unstable or shows decrease with repeated injections.
Possible Solutions
• Electron multiplier is faulty. See
• There is a problem with the filament emission current control. See
• GC temperature ramp does not continue to a high enough temperature to elute high
boiling point compounds. Multiple injections cause these compounds to accumulate in
column, thus reducing sensitivity. Extend upper temperature or time at upper
temperature in GC oven ramp.
• Injection port liner or capillary column are contaminated. Replace the injection port liner
and trim the capillary column.
• Ion source temperature is too low, causing it to contaminate too quickly. Clean the ion
volume, lenses, and prefilter and then raise the ion source temperature. See
Ion Source, Lenses and Prefilter”
for more information.
• Ion volume or holder may be loose. Adjust the ball valve to ensure they fit snugly.
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 ...