Waters HPLC - Page 95

Troubleshooting 3-11
Erratic retention time troubleshooting
Retention time
problem
No
Yes
Retention
time erratic?
Ret time
incorrect, but
reproducible?
Yes
No
Are pressure
fluctuations same
as during normal
operation?
Chemistry
problem?
Yes
Yes
No
No
Mobile phase
degrading?
Use fresh
mobile phase
Prime pump
to remove
air bubbles
No
Problem
corrected?
Mobile phase
separating?
Yes
No
Stir mobile
phase
Problem Is
operation
Wrong
column
equilibration?
Equilibrate
column
No
Yes
Temp
fluctuations
Stabilize
environment
No
Sparge conditions
causing solvent
components to
evaporate at
different rates
Yes
Suggested actions:
- Decrease sparge
- Use separate
reservoir for pure
solvents
rate
- Allow pump to
make mixture.
Mixing does not
apply to RI
detectors.
Yes
No
Yes
Column
contaminated?
Suggested actions:
-Troubleshoot
column
- Improve sample
prep
Yes
No
No
System
leaking?
Isolate and
troubleshoot
leak
Troubleshoot pump:
- Seals
- Check valves
- Plunger
Call Waters
technical service
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