Conductivity Curve Problems - GE HEALTHCARE AKTAprime plus Operating Instructions Manual

6 Troubleshooting
6.1 UV curve problems
Error symptom
Low sensitivity
6.2

Conductivity curve problems

Error symptom
Baseline drift or noisy
signal
Conductivity measure-
ment with the same
buffer appears to de-
crease over time
50
Possible cause
Aging UV lamp
UV lamp in wrong po-
sition
The theoretical extinc-
tion coefficient too
low
Possible cause
Air in the pump or the
flow cell
Leaking tube connec-
tions
Incorrect mixer func-
tion
Dirty conductivity cell
Column not equilibrat-
ed
Dirty flow cell
Decrease in ambient
temperature
ÄKTAprime plus Operating Instructions 28-9597-89 AC
Corrective action
Check the lamp run time according
to and replace if necessary. Refer
to ÄKTAprime plus User Manual.
Check that the lamp position and
the filter position are both set to
the wavelength to be used, 280 nm
or 254 nm. Refer to ÄKTAprime plus
User Manual.
Calculate the theoretical extinction
coefficient of the protein. If it is ze-
ro or very low at 280 nm, the pro-
tein cannot be detected.
Corrective action
Check the flow restrictor after the
flow cell.
Tighten the clamps. If necessary,
replace the clamps.
Check the mixer function by plac-
ing a stirrer bar on top of the mixer
housing. The stirrer bar should ro-
tate when the system is in Run
mode. The mixer function can also
be checked by running the installa-
tion test.
Clean the conductivity cell by
flushing 1 M NaOH or 20% ethanol.
Equilibrate the column. If neces-
sary, clean the column using a
method plan for column cleaning.
Clean the flow cell according to
procedure in Monitor User Manual.
Use a temperature compensation
factor. See Monitor User Manual.