7
Diagnostics and Troubleshooting
Troubleshooting
Thermo Scientific
TSQ Quantum XLS and TSQ Quantum GC User Guide
139
Issue:
Turbo pump
shuts off during
operation.
Possible cause/solution
• The foreline pressure is too high. Check for leaks in the foreline.
Issue:
Unexpected full
ventilation occurs.
Possible causes/solutions
• A gross leak is present. Check for leaks.
• The system was vented through the inlet valve. Close and plug the inlet valve.
• The GC column broke at the transfer line. Replace the GC column. See
Installing a GC Capillary Column”
• The foreline was cut. Replace the foreline hose.
Issue:
Vacuum is faulty.
Possible Solutions
• A gross leak is present. Check for leaks.
• The pressure in the analyzer region of the vacuum manifold, as measured by the ion
gauge, must be below the pressures listed in
Linearity Issues
Linearity issues occur when a plot of intensity versus concentration of a known compound is
not linear. Poor instrument operating conditions can cause linearity problems. Additionally,
certain compounds do not give a desired linear response due to chromatographic activity.
A well-maintained instrument provides good linear response over a wide range of
concentrations for most compounds. Like any instrument, however, the TSQ Quantum XLS
and TSQ Quantum GC has a saturation point.
Perform routine injector and column maintenance to minimize linearity problems. Usually, a
hardware fault that affects linearity shows different issues than those that might be attributed
to linearity.
Issue:
Calibration plots
not sufficiently linear.
Possible causes/solutions
• High-end standards are too concentrated for the MS. Use the split injection technique to
decrease the amount of sample or lower emission current to reduce MS sensitivity.
• The ion volume and lenses are dirty. Clean ion volume and lenses as described in
“Cleaning Ion Source Components”
• The electron multiplier setting is incorrect. Run Auto Tune - Calibration as described in
• The injection port liner or capillary column is dirty. Change the injection port liner and
trim the capillary column.