2
Troubleshooting
Investigating Sensitivity Issues
Thermo Scientific
ISQ 7000 Hardware Manual
139
Poor sensitivity or sudden loss in sensitivity.
Poor high mass response.
Poor sensitivity in CI mode.
Possible Remedies
Tune the system.
Refill the calibration gas reservoir.
Perform a daily tune check to determine if you are getting the correct response to the calibration gas. Verify the leak check is below 7%.
If the calibration gas sensitivity is low, switch to the second filament and tune the ISQ 7000 instrument to determine if the calibration gas
sensitivity is recovered. If so, continue to run with the second filament.
Make sure the ion volume is properly positioned. See
for details. If you recently performed maintenance on your ion
source, remove the ion source, verify that it is assembled correctly, and reinsert it into the ISQ 7000 instrument.
Make sure the GC column does not extend into the ion source. Use the column measuring tool to ensure the column is the correct length.
Make sure the GC column did not break inside the ion source. If necessary, remove the pieces from the ion source.
Clean or replace the GC injection port liner to remove possible contamination, trim the injector end of the column, or replace the septum.
Make sure the source magnets are positioned so that their south poles are facing up. Reposition them, if necessary.
Clean the ion source and lenses. See
Cleaning the Ion Source Cartridge
for details.
Make sure the right type of ion volume is installed. EI and CI require different ion volumes and cannot be used interchangeably.
Check the electron multiplier gain and make sure it is not too low. Retune the detector gain. Replace the electron multiplier, if necessary.
See
Replacing the Electron Multiplier
for details.
Possible Remedies
Run a resolution tune to make sure the resolution is set correctly.
Refill the calibration gas reservoir.
Clean the ion volume and lenses. See
Cleaning the Ion Source Cartridge
Reduce the ion source temperature to reduce the amount of thermal decomposition and fragmentation of your analyte.
Check the system for air leaks and address them. See
for details.
Possible Remedies
Make sure a CI ion volume is installed.
Make sure the electron entrance hole on the CI ion volume is clean. Use a dental pick or old syringe needle to clear the hole. See
if you need help locating the electron entrance hole.
Содержание ISQ 7000
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Страница 174: ...2 Troubleshooting Contacting Technical Support 146 ISQ 7000 Hardware Manual Thermo Scientific ...
Страница 400: ...3 Advanced Maintenance Replacing Fans and Filters 372 ISQ 7000 Hardware Manual Thermo Scientific ...