Waters 2414 - Page 110

June 11, 2015, 715004754 Rev. A
Page 110
Use the following table to troubleshoot problems with retention times.
Table 7–4: Troubleshooting problems with retention times
Symptom Possible cause Corrective action
Erratic retention times Air bubble in pump head Degas all solvents, prime
pump (see “Solvent
degassing methods” on
page 60).
Malfunctioning pump check
valves
Inspect and clean,
replace, or rebuild pump
check valves.
Leaking pump seals Replace pump seals.
Separation chemistry Confirm that the mobile
phase and column are
suitable for the analysis.
Clogged solvent filters Replace filters.
Increased retention
times
Incorrect flow rate Verify flow rate.
Incorrect solvent composition Change solvent
composition.
Column heater module not on Power-on column heater
module.
Column not equilibrated Equilibrate column.
Incorrect column or guard
column
Use correct column or
guard column.
Doubled retention times Air bubble in pump head Prime pump to remove
bubble.
Malfunctioning pump check
valve(s)
Inspect and clean,
replace, or rebuild pump
check valve(s).
Broken pump plunger Replace the plunger.
Reduced retention
times
Incorrect flow rate Verify flow rate.
Incorrect solvent composition Change composition.
High column temperature Reduce column
temperature.
Incorrect column
pretreatment
See column manual.
Column contaminated Clean or replace column.
Incorrect column or guard
column
Use correct column or
guard column.