8
2.2.1 High baseline noise
Table 2.4 lists potential causes, confirmation methods, and methods for solving
problems that may arise due to high baseline noise.
Table 2.4 Dealing with High Baseline Noise
Cause Confirmation
Method
What to Do
Variations in pump pressure
Stop solvent delivery.
If the noise
disappears, the
cause lies in the
pump. If the noise
remains, the cause
lies in the UV
detector.
See Section 2.1.3.
(Particularly when the
pressure monitor shows
large variations in
pressure.)
Mixing noise (when running a
gradient program or using a
post-column derivatization
system)
See above
Add an extra mixer or
damper to the pump
Detector cell problems
Bubbles
Contamination
Leakage
Refer to the
maintenance manual of
the UV detector
Decrease in the light intensity
of the detector
Light source deterioration
Mirror deterioration
Refer to the
maintenance manual of
the UV detector
2.2.2 Spike-shaped baseline noise
Table 2.5 lists potential causes, confirmation methods, and methods for dealing with
spike-shaped baseline noise.
Table 2.5 Dealing with Spike-Shaped Baseline Noise
Cause
Confirmation Method
What to Do
Bubbles in the cell (In this
case, spike-shaped noise
occurs only toward
increasing absorption)
Stop solvent delivery. If the
noise stops, there are
probably air bubbles in the
cell
Refer to the
maintenance
manual for the UV
detector
Electrical noise
Ground the
instrument