Metrohm 761 SD Compact IC - Manual (Page 100)

6 Notes – Maintenance – Faults
761 SD Compact IC / Instructions for Use 8. 761.1043
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rinsed free of salt with methanol/water (1:4) to avoid crystallisation of
eluent salts with the corresponding subsequent damage.
The connections to the separating column and suppressor module
must be removed for rinsing. The two capillaries 35 and 37 (see Figure
3) must be directly connected together using a coupling 54
(6.2744.040). Rinse with methanol/water (1:4) until the conductivity
drops below 10 µ S/cm.
6.2.4 Changing separating columns
If you wish to replace the separating column 36 by a new column, pro-
ceed as follows:
1 Remove old column
• Switch off the high-pressure pump and wait for the pressure
to drop.
• Unscrew the separating column 36 from the suppressor inlet
capillary 37.
• Unscrew the separating column 36 from the connection capil-
lary 35.
2 Connect the new column to the injector
• Remove the screw caps from the new separating column 36.
• Screw the inlet end of the separating column 36 (note flow di-
rection) to the connection capillary 35.
3 Rinse the column
• Place a beaker beneath the column outlet.
• Switch on the high-pressure pump and rinse the column with
eluent for approx. 10 minutes, then switch off the pump.
4 Connect the column to the suppressor
• Screw the outlet end of the separating column 36 to the sup-
pressor inlet capillary 37.
6.2.5 Maintenance work on the pump head
In many cases, an unstable baseline (pulsation or flow rate fluctuations)
can be traced to contaminated valves or faulty, leaking piston seals on
the high-pressure pump. Proceed as follows for cleaning contaminated
valves and/or replacement of parts subject to wear such as pistons,
piston seals and valves: