4.3.2.2 Erratic retention times
Suspected cause Possible solution
The system is not stabilized or chemically
equilibrated
• Allow all system components (such as the
column and detector) sufficient time to
stabilize and chemically equilibrate.
• Ensure proper operating conditions for the
application (such as mobile phase, detector
settings, and detector type).
• Verify the initial hold at the beginning of the
gradient.
• Ensure that the flow controllers were
autozeroed with the solvent currently in use
at a temperature close to the current lab
temperature.
See also: The component’s overview and
maintenance guide, or the column care and
use manual, on the documentation CD for
recommended equilibration times.
Note: When running an automated gradient
method, ensure that there is sufficient and
reproducible equilibration times used between
injections.
Erratic solvent manager pressure • Prime the solvents.
• Run leak tests.
• Analyze the pressure trace in the Console
for stability.
Injection volume or sample concentration is too
high; disrupting equilibrium
Reduce the injection volume or dilute the
sample with initial mobile phase.
Ambient temperature fluctuations Stabilize the operating environment
temperature (for a minimum of 30 minutes).
If the problem persists:
• Run the column heater temperature at 5 °C
above ambient.
• Close any open air vents.
• Contact your Waters service
representative.
November 26, 2019, 715003588 Revision C
Page 66
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