Metrohm 761 Compact IC - Manual (Page 184)

5 Notes – Maintenance – Faults
761 Compact IC
174
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 procedure
can be used. In recycling the eluent exiting the outlet capillary of the de-
tector block is led back directly to the eluent supply vessel 67. The IC
system is thus quickly ready for new injections without a long condition-
ing period.
Instead of threaded stopper 65 the 4.420.0311 Tubing nipple (M6),
which belongs to the accessories of the 6.1602.160 Bottle attachment,
can be used together with the second E.301.0021 O-ring (which is also
included) for returning the eluent (see section 2.6.3).
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 761 Compact IC 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 connections to the separating column and the suppres-
sor module are removed; the two capillaries 28 and 45 (see Fig. 13 and
Fig. 14) are directly connected to each other using coupling 33
(6.2620.060). Rinse with methanol/water (1:4) until the conductivity
drops below 10 µ S/cm.
5.2.5 Changing separating columns
Identical separation system
If you wish to replace an IC separating column by a column of the same
type, proceed as follows (see Fig. 14 and Fig. 16):
1 Remove old column
• Switch off high-pressure pump and wait for pressure to drop.
• Unscrew column 81 from inlet capillary 45 of the detector
block or from suppressor inlet capillary 96.
• Unscrew column 81 from column connection capillary 28 or
the precolumn.