9
2.2.3 Large baseline drift
Table 2.6 lists potential causes, confirmation methods, and methods for dealing with
large baseline drift.
Table 2.6 Dealing with Large Baseline Drift
Cause
Confirmation Method
What to Do
Insufficient solvent
replacement
Does the drift level decrease with
time?
Wait (increase the
flow rate if
necessary)
Insufficient column
equilibration
See above
See above
Time variation of
eluent (composition,
dissolved gas level,
etc.)
Use an eluent that is
better suited to the
conditions
Detector instability
(cell bubbles,
contamination,
leakage, etc.)
Refer to the
maintenance manual
of the UV detector
Eluent contamination
Lengthen the detector
wavelength. If the drift
decreases, there is a problem
with the eluent
Use a higher grade
eluent
Contamination of
pump or equipment
upstream from the
pump
Lengthen the detector
wavelength. If the drift becomes
smaller, there is a problem with
equipment contamination
Clean the
contaminated device
using an acid or an
alkaline solution
(See Section 4.3)
Contamination
downstream from the
pump (manual
injector, autosampler,
column, tubing,
fittings)
Remove the device or part that
appears to be contaminated and
check the drift
Clean or replace the
contaminated device
or part
2.2.4 Periodic drift
Table 2.7 lists a potential cause, a confirmation method, and a method for dealing
with periodic drift.
