Thermo Scientific Dionex UltiMate 3000 Series, Руководство по эксплуатации

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UltiMate 3000 Series:
NCS-3500RS and NCP-3200RS
Operating Instructions Page 167
Problem Probable Cause Remedial Action
Either no peaks or only few,
poorly resolved peaks appear
in the chromatogram.
With direct injection or
preconcentration: The solvent
contains too much organic, the
solvent does not contain enough
organic in the solvent, or the
mobile phase is wrong.
Optimize the
chromatographic parameters.
With preconcentration: The trap
column is too short, the flow rate
of the loading pump is too high,
and/or the loading time is too
long. The three items interact: If
the trap column is too short,
peaks may be lost because they
are not retained. If the loading
time is too long or if the loading
flow is too high, hydrophilic
peaks may be lost. This also
affects the reproducibility
because the proteins are
transported a long way into the
trap column.
Consider the following: Use a
longer trap column, reduce
the flow rate from the loading
pump, and/or reduce the
loading time.
Reproducible ghost peaks in
the chromatogram.
The degassing channels are
contaminated.
Rinse the degassing channels
( → Solvent Rack manual ).
The eluents are degraded, dirty or
of poor purity/quality.
Use fresh solvent. Use fresh
and appropriate solvents (MS-
grade).
Contamination occurs
somewhere in the system.
Flush the system with an
appropriate solvent.
Additional peaks appear in
the injection peak.
With gradients, the equilibration
time after the flush cycle is too
short.
Extend the equilibration time.
There is excessive dead volume. Eliminate any dead volume.
Triangular peaks The column is overloaded (the
concentration of the sample is too
high).
Dilute the sample.
Spikes There is electrical interference
from other modules.
Isolate the electrical circuit
from strong current
consumers. Consider
installing an uninterruptible
power supply (UPS).
For additional causes, refer to the
operating instructions for the
detector.
→ Detector manual
Negative peaks Sample solvent and mobile phase
differ in composition.
Dissolve the sample in the
mobile phase.