Thermo Scientific Vanquish VF-D20 Operating Manual page 162

8 • Troubleshooting
Symptom
High backpressure
Negative peaks
Loss of response
Inability to
autozero the
signal
Liquid in the gas
exhaust
Page 162
Possible Cause
Nebulizer
nozzle/capillary clogged
Wrong polarization of
the analog output
Change in parameters
Drain pump failed
Gas flow turned off
Reduced gas flow
Gas leaking
Autozero on a peak or
void signal
Autozero on a very noisy
signal
Flooding inside the
detector (pump flow
turned on while no gas
flow present)
Remedial Action
Poor solubility of analyte during nebulization/analyte build-up.
Check the backpressure of the nebulizer:
1. Remove the nebulizer from the detector (see
page 128).
2. Set up a direct flow connection from the pump to the nebulizer.
Make sure no other module is connected in between.
3. Carefully flow liquid through the nebulizer capillary from the
pump. The backpressure of the nebulizer is typically below
10 bars. Liquid should exit the capillary in drops. If the
backpressure rises in the pump, then a blockage is present in the
nebulizer capillary. Contact Technical Support.
To avoid blockage in the nebulizer, always use the detector with
an appropriate mobile-phase composition to maintain solubility.
Contact Technical Support.
Check that the detector is turned on and the data acquisition is
on. Check the parameter settings.
Check that the drain pump is turned on.
Check that the gas flow is turned on in the detector and the gas
supply.
•
Make sure that the gas is flowing into the detector.
•
Check the nebulizer gas pressure and the gas supply pressure.
•
Check gas filter assembly. If necessary, replace the gas filter
assembly (see section 7.8, page
Check the gas connections and the gas inlet and exhaust tubes.
Remedy the gas leak and/or replace the gas tubes (see
section 7.5, page 125).
The Autozero occurred on a relatively flat section of the
chromatogram.
Reduce the noise or increase the current range.
Flooding can occur if the detector is turned off while liquid is still
flowing into the detector.
See section 8.3.3 Resolving Flooding In the Detector, page
Vanquish Charged Aerosol Detectors Operating Manual
section 7.7,
131).
160.