Waters Alliance e2695 Operator's Manual page 172

Table 8–9: Chromatography troubleshooting (continued)
Symptom
Decreased retention times
Reproducibility errors
Baseline drift, rapid
Baseline drift, slow
Possible cause
Incorrect flow rate
Incorrect solvent composition
High column temperature
Incorrect mobile phase
Column contaminated
Incorrect column
Solvent not properly degassed Degas solvent.
Solvent not properly degassed Degas solvent.
Incorrect chemistry/integration Evaluate
Sample management system
problem
Column not equilibrated
Detector not allowed to warm
up
Solvent contaminated
Solvent not properly degassed
(rapid or slow drift)
Flow fluctuations (rapid or
slow drift)
Incorrect wavelength for
solvent
Solvent contaminated
Decreased UV lamp energy
Ambient temperature
fluctuations
UV detector flow cell leaking
(internal, cross-port)
Dirty flow cell
February 27, 2018, 715003794 Rev. C
Page 172
Corrective action
Change flow rate.
Change composition, evaluate
GPV performance.
Reduce column temperature.
Replace with correct mobile
phase.
Clean/replace column.
Use correct column.
chemistry/integration.
Troubleshoot sample
management system.
Equilibrate column.
Allow detector to warm up until
baseline is stable. Time varies
with wavelength and
sensitivity.
Use fresh solvent.
Degas solvent.
Prime solvent management
system, replace pump seals,
check valves (see "Erratic
Retention Times" symptom).
Check that solvent does not
have absorbence at the
wavelength used.
Use fresh solvent.
Determine lamp energy using
detector diagnostics.
Stabilize operating
environment temperature
enough to allow full
equilibration.
Inspect flow cell, tighten
connections.
Clean flow cell.