Waters ACQUITY UPLC M-Class System Manual page 66

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