Thermo Scientific Dionex UltiMate 3000 Series Operating Instructions Manual page 173

Problem
Shifts in retention time for a
longer period
Retention time outside the
expected range
High noise level, non-periodic
baseline fluctuation
Pressure pulsation or
inconstant pressure
Operating Instructions
Probable Cause
When changing solvents, the
previous solvent has not been
removed completely from the NC
pump.
Periods of inactivity (interruption
of operation) or changed
operating conditions
The thermal flow sensors or
pressure transducers may have a
small drift.
The solvent settings are incorrect.
Solvents were pre-mixed and not
used for a longer period of time.
Pre-mixed solvents are too old.
The eluent is degraded or of poor
quality/purity.
For additional causes, refer to the
operating instructions for the
detector.
The solvent is not degassed
sufficiently.
The solvent is degraded.
There are pressure fluctuations
from the pump.
There are pressure fluctuations
from the loading pump.
There are air bubbles in the
system.
UltiMate 3000 Series:
NCS-3500RS and NCP-3200RS
Remedial Action
Purge the NC pump
(→ page 73).
When pump operation was
interrupted (periods of
inactivity) or when the
operating conditions have
been changed, it can take
some time until the system
has reached the optimally
stable operating conditions
again.
ProFlow flow meter: Perform
a zero balance test for the
thermal flow sensors
(→ page 172).
Classic flow meter: Calibrate
the pressure transducers
(→ page 172).
Check and correct the settings
for the solvents in
Chromeleon.
Purge the pump (→ page 72).
Use fresh eluent. Use fresh
and appropriate solvents (MS-
grade). Purge the pump
(→ page 72).
Use fresh eluent. Use fresh
and appropriate solvents (MS-
grade).
→ Detector manual
Degas the solvent.
Use fresh solvent.
Purge the pump (→ page 72).
Check the compression
values. Perform the remedial
actions (→ page 174).
Purge the pump (→ page 72).
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