Corrective action
Possible cause
Error symptom
Check that the electrode cable is
connected properly.
Problem with elec-
trode
Incorrect or unstable
pH reading
Check that the electrode is correct-
ly inserted in the flow cell and, if
necessary, hand-tighten the nut.
Check that the pH electrode is not
broken.
Calibrate the pH electrode.
Clean the pH electrode if required,
see
Monitor pH/C-900 User Manual
.
Compare the response of the pH
electrode with that of another pH
electrode. If the response differ
greatly, the electrode may require
cleaning or replacement.
In organic solvents such as
ethanol, methanol and acetonitrile,
stable pH measurements are not
possible since dehydration of the
membrane will occur. It is recom-
mended that the pH electrode is
not used in applications using or-
ganic solvents. Mount the dummy
electrode instead.
Check that the pump and valves
operate correctly.
Incorrect pump or
valve operation
If air in the flow cell is suspected,
tap the flow cell carefully or tilt it
to remove the air. Alternatively,
flush the cell with buffer at 20
ml/min (E 100 system) or 10 ml/min
(E 10 system) for 1/2 min. Use the
flow restrictor FR-902 after the pH
electrode.
Air in the flow cell
There may be interference from
static fields. Connect the pH flow
cell and the rear panel of the
monitor using a standard laborato-
ry 4 mm “banana plug” cable.
Static interference
54
ÄKTAprime plus Operating Instructions 28-9597-89 AC
6 Troubleshooting
6.3 pH curve problems