Possible cause and actionProblem
•
Rapid changes of the refractive index
The refractive index of the buffer changes rapidly in quick IEX
gradients. The rapid change may cause light spreading effects
and disturb the shape of the protein peaks in the U9-L 2 mm flow
cell.
Run with reversed flow direction through the 2 mm cell: connect
the inlet tubing at the bottom and the outlet tubing at the top of
the flow cell.
Note:
The standard tubing (7) between the UV monitor and the conduc-
tivity monitor is too short (170 mm) for mounting the monitor for
reversed flow direction. Perform the following actions:
1
Replace the standard tubing with a tubing that is 210 mm long.
2
Update the total delay volume. The increase in volume depends
on the inner diameter (i.d.) of the tubing:
-
i.d. 0.25 mm : 2 µl
-
i.d. 0.50 mm : 8 µl
-
i.d. 0.75 mm: 18 µl
-
i.d. 1.0 mm: 32 µl
Distorted protein peaks in
IEX gradients (for example
step gradients).
Conductivity monitor
Possible cause and actionProblem
Test was performed at cold room temperature and the conductiv-
ity temperature compensation factor was not optimized.
The conductivity part of the
system performance test
failed
In the System Settings dialog, select Conductivity:Cond temp
compensation and set the Compensation factor to 2.1%.
•
Internal errors
See error log. Restart instrument and retry. If this problem recurs,
generate a System error report and contact Service.
The cell constant measure-
ment has been aborted
•
Air in the Conductivity flow cell
Flush the Conductivity flow cell with water.
•
Solids in the Conductivity flow cell
Clean the Conductivity cell. See Section 7.6.10 Clean the Conduc-
tivity flow cell, on page 300.
Unstable conductivity
ÄKTA pure User Manual 29119969 AB 367
8 Troubleshooting
8.3 Troubleshooting: Monitors
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