Dionex UltiMate 3000 - Accessories and Spare Parts

UltiMate 3000 Nano and Cap - System Installation and Application
59
Problem Probable Cause Remedial Action
Poor reproducibility (cont'd) Carry-over occurs in the system. Flush the needle using an
appropriate solvent.
The capillary connections are not
installed properly or they are not
tight.
Check and tighten the capillary
connections.
Exchange the needle if necessary
(→ Autosampler manual).
There are dead volumes in the
capillary connections.
Replace the fittings.
There are dead volumes in the
trap column connections.
→ section 3.7
The pump head seals are not
tight.
Replace the seals (→ Pump
manual).
The sample is unstable and
decomposes.
Use new sample or change the
conditions.
The gradient is not reproducible. Change the gradient.
Check the pump function and
degassing.
Check the suction frits for
obstruction and exchange as
necessary.
The environmental conditions are
unstable.
Make sure that the temperature
and air humidity are constant.
(Use a column thermostat.)
Contamination occurs
somewhere in the system.
Flush the system using an
appropriate solvent.
No flow The system is leaking. Find and eliminate the leak.
The check valves are not
installed properly in the pump
(not in direction of flow) or
defective.
Correctly install or replace the
check valves (→ Pump manual).
There is air in the solvent or in
the pump head(s).
Purge the pump (→ Pump
manual).
The pump's inline filter is
clogged.
Replace the filter (→ Pump
manual).
Flow fluctuation The inlet path is blocked. Check the pump's inlet lines,
filter, proportioning valve etc. for
signs of blockage.
There is air in the inlet path.
Purge the pump (→ Pump
manual) and check the degasser.
The pump's check valves are
dirty or defective.
Clean or replace the check valves
if necessary (→ Pump manual).
The pump head seals are not
tight.
Replace the seals (→ Pump
manual).
Poor degassing There is a leak in the capillaries
or solvent lines or there are loose
connections.
Inspect the capillary and solvent
tube connections for leakage;
tighten loose fitting connections.
The flow rate is too high. Reduce the flow rate.
UV signal drift during the
gradient
In applications with TFA, the
TFA concentration is incorrect. If
the signal drifts upward, solvent
B contains too much TFA and
vice versa.
Increase or reduce the TFA
concentration as needed.