Metrohm 732 IC Detector - Manual (Page 144)

5.2 Maintenance and servicing
732 IC Detector / 733 IC Separation Center
137
corrosive chemicals, it may be necessary to shorten the interval be-
tween servicing.
The Metrohm service department is always willing to offer expert advice
on the maintenance and servicing of all Metrohm instruments.
5.2.2 Passivation
Passivation of the entire IC system (without column) by rinsing with
20...50 mL 0.2 mol/L HNO
3
is appropriate in the following cases:
• in the installation
(only with non metal-free IC systems, see section 2.6.7)
• if the separation system is changed
(only with non metal-free IC systems, see section 5.2.5)
• if exceptional changes are observed in the
measurement properties of the cell
(with metal-free and non metal-free IC systems).
For passivation the separating column is removed from the 733 IC
Separation Center. The two capillaries 67 67 and 82 82 (see Fig. 16 and
Fig. 17) are directly connected to each other using the 6.2620.060
Coupling enclosed with the accessories.
5.2.3 Recycling
To keep the eluent consumption between injections to a minimum
when the system is at rest (e.g. overnight), the so-called recycling pro-
cedure can be used. In recycling the eluent exiting the outlet capillary of
the detector block is led back directly to the eluent supply vessel. The
IC system is thus quickly ready for new injections without a long condi-
tioning period.
The recycling procedure must not be used
• in operation with the suppressor module,
• with alkaline eluents,
• with the 6.1010.000 IC Cation column METROSEP Cation 1-2.
5.2.4 Shutdown
If the 732/733 IC-System is shut down for a considerable length of time,
the entire IC system (without column and suppressor) must be rinsed
free from salt with methanol/water (1:4) to avoid crystallization of elu-
ent salts with the corresponding subsequent damage.
For rinsing the separating column is removed; the two capillaries 67
67
and 82 82 (see Fig. 16 and Fig. 17) are directly connected to each other
with the 6.2620.060 Coupling enclosed with the accessories. Rinse with
methanol/water (1:4) until the conductivity drops below 10 µ S/cm.