Amersham Pharmacia Biotech AKTA design pH/C-900, User Manual

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Fault Action
7 Check the slope (see section 3.6 Calibrating pH).
If it is outside the range 80–105% or the asymmetry potential
deviates more than 60 mV from 0 mV, clean the pH
electrode. Recalibrate and if the problem persists, replace
the pH electrode.
8 Clean the pH electrode if required, see section 4.3 Cleaning
the pH electrode.
9 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.
10 There may be interference from other equipment. Connect
the pH flow cell and the rear panel of the monitor using a
standard laboratory 4 mm “banana plug” cable.
11 Check that the pH electrode has been calibrated at the
correct temperature.
12 In organic solvents such as ethanol, methanol and
acetonitrile, stable pH measurements are not possible since
dehydration of the membrane will occur. It is recommended
that the pH electrode is not used in applications using
organic solvents. Mount the dummy electrode instead.
13 Clogged liquid junction. Refer to section 4.3 Cleaning the pH
electrode.
pH values vary with varied 1 Replace the pH electrode.
back-pressure
Conductivity measurement
Fault Action
Incorrect or unstable reading 1 Check that the conductivity flow cell cable is connected
properly to the rear of the instrument.
2 Check that the pump and valves operate correctly.
3 If temperature compensation is being used, check that the
temperature sensor is calibrated, and that the correct
temperature compensation factor is in use.
4 Check that the column is equilibrated. If necessary clean the
column.
5 Check the operation of the mixer.
Baseline drift or noisy signal 1 There may be air in the flow cell. Use a flow restrictor after
the flow cell.
2 Check for leaking tubing connections.
3 Check the column is equilibrated. If necessary clean the
column.
4 Check the operation of the mixer and the pump.
5 Clean the flow cell according to procedure in section
4.5 Cleaning the conductivity flow cell.
Monitor pH/C-900
User Manual 18-1120-06 Edition AC 16
5
Trouble shooting
18-1120-06_AC.qxd 1999-04-14 14:16 Sida 16 (1,1)