Thermo Scientific Corona Veo, Operating Manual

Page: 232 / 262

8 • Troubleshooting
Page 232 Charged Aerosol Detectors Corona Veo (RS) Operating Manual
8.5.4.6
Ghost Peaks, Negative Peaks and Spikes
Symptom Possible Cause Remedial Action
Ghost peaks Contamination (typically
injector or column) Flush the system using an appropriate solvent.
Degassing channels
contaminated Purge the pump (all channels) to rinse the degassing channels
(refer to
Pump Operating Manual ).
Late eluting peak from
previous analysis Extend the run time.
Increase the elution strength of the gradient (higher organic
content). At the end of the run, flush the column with strong
eluent.
Solvents are degraded,
dirty or their purity is
insufficient •
Use freshly prepared solvent.
• Observe the Mobile Phase Guidelines for the Detector in
section 6.5.1, page 123 .
Negative peaks Sample and mobile
phase differ in
composition Make sure that the sample dissolves in the mobile phase.
Wrong polarization of
the analog output Contact Technical Support.
Spikes Column temperature
significantly above
boiling point of mobile
phase Reduce the column temperature or install a post-column cooler.
Electrical interferences
from other instruments Avoid operation of equipment generating strong electric or
magnetic fields in close proximity. Do not connect equipment that
may cause power disturbances to the same power network used
to supply the system.
Ground the detector using heavy gauge wire from the
thumbscrew ground terminal that is located on the power supply
module to the main power ground.