Thermo Scientific thermoscientific Vanquish UHPLC System, Operating Manual

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8 • Troubleshooting
Page 122 UHPLC System
Operating Manual
Possible Cause Remedial Action
UV/VIS lamp not stable Allow the lamp and optics to warm up for at least 60 minutes. If the lamp is old, you
may need to replace the detector lamp (see
Detector Operating Manual ).
A new lamp may need burn-in time before the first analysis. For details, refer to the
Detector Operating Manual .
Absorption of eluent
changes when gradient
is run Absorbing additives may change the absorption spectrum, depending on the
solvent. Consider varying additive concentrations to level the drift.
Non-periodic baseline fluctuation, high noise
Possible Cause Remedial Action
Pressure fluctuations
from pump Purge the pump; check general function (refer to Pump Operating Manual ).
Air trapped in the
system Purge the system as necessary (refer to Pump Operating Manual ).
UV/VIS lamp old or not
properly installed Check that the lamp is correctly installed. Replace the lamp (refer to Detector
Operating Manual ).
Improper reference
wavelength The sample must not absorb in the range of the reference wavelength. Consider
using a method without reference wavelength.
Detector response time
too short Select a suitable response time.
Improper wavelength
or optical bandwidth Select an appropriate wavelength.
Select a higher bandwidth In particular with critical conditions (low absorption, few
light).
Flow cell not properly
installed Check that the flow cell is installed properly (refer to Detector Operating Manual ).
Detector defective Contact Technical Support.
Optical transmission of
the flow cell too low
(Vanquish system with
VH-D10 detector only) Check the lamp age and replace the lamp, if necessary. Use the Cell Transmission
Check / Flow Cell Wash button on the ePanel for the module and follow the
instructions. For this procedure, a diagnostic cell for the VH‑D10 is required. If you
do not have a diagnostic cell, compare the cell transmission (light intensity) values
of the flow cell before and after a wash procedure and check whether the cell
transmission (light intensity) has increased. If it has not increased, perform an
extended wash cycle and check whether the cell transmission (light intensity) has
increased.
Periodic baseline fluctuation, pulsation
Possible Cause Remedial Action
Pressure fluctuations
from pump Purge the pump; check general function (refer to Pump Operating Manual ).
Air trapped in the
system Purge the system (refer to Pump Operating Manual ).
Improper reference
wavelength The sample must not absorb in the range of the reference wavelength. Consider
using a method without reference wavelength.