Bio-Rad BioLogic Signal Import Module (SIM) - Manual (Page 214)

12.3 TROUBLESHOOTING THE UV DETECTOR AND UV TRACE
Problem Possible Cause Solution
UV baseline is Air bubbles trapped in the
unstable or noisy. analytical 5 mm Z cell are the
most common cause of noisy
UV baseline shows UV baselines.
a reproducible
zig-zag or saw-
Note: Always degas buffers
tooth trace. before use.
Excessive pump Air bubbles trapped in the
pulsations exhibited pumpheads can produce
as regular noise
exaggerated pulsations which
on the baseline. appear as a noisy baseline.
Baseline noise Noise spikes can also be
continues when caused by external
pumps are environmental influences.
turned off.
TROUBLESHOOTING MAINTENANCE AND TROUBLESHOOTING
12-7
1. Degas buffers by stirring vigorously under
vacuum for approximately 20 minutes. Use a
heavy-wall side-arm Erlenmeyer flask, as
standard flasks may implode under vacuum.
2. Plumb the Z cell with the column outlet
connected to the bottom of the flow cell. This
will force air bubbles to rise to the top of the
flow cell and dissipate.
3. Use of the 40 psi backpressure regulator
supplied with the DuoFlow system will remove
most air bubbles. Place it directly after the
conductivity flow cell and run buffer for several
minutes.
If the column being used cannot be run with the
backpressure regulator and air bubbles are a
continuing problem (for example, during some
affinity chromatography steps), use the 2mm
path length cuvette cell. The straight line flow of
the cuvette cell makes bubble removal easier.
1. Purge the pumpheads to remove the bubble.
Refer to Section 11.3.1, Priming the
Workstation Pump and Removing Trapped Air
Bubbles.
1. If the spikes occur at regular intervals (for
example, once every 20-30 sec), check for the
presence of heating baths, drying ovens, or
other heating devices on the same electrical
circuit or in close proximity to the DuoFlow
system. Turn off these devices to see if the
problem goes away.