Metrohm 792 Basic IC - Manual (Page 151)

5 Notes – Maintenance – Faults
792 Basic IC
142
5.1.5 Suppressor module
Protection
To avoid contamination of the suppressor module by foreign particles
or bacterial growth, the two 6.2821.100 Filter units PEEK (see sec-
tion 2.3.5) supplied must be installed between peristaltic pump and inlet
capillaries of the suppressor module (see section 2.8.2).
Operation
The Metrohm Suppressor Module MSM comprises a total of 3 sup-
pressor units which are in turn used for suppression, regenerated with
sulfuric acid and rinsed with water. To record every new chromatogram
under comparable conditions, work is normally carried out with freshly
regenerated suppressor. Switching takes place automatically together
with the valve switching.
For operation of the suppressor module, a two-channel peristaltic
pump is needed which conveys the regeneration solution (normally
20 mmol/L H
2
SO
4
) and the rinsing solution (normally dist. H
2
O) to the
suppressor units (flow rate of 0.5 mL/min).
The suppressor units must never be regenerated with H
2
SO
4
in the
same flow direction used for the eluent. You should thus always install
the inlet and outlet capillaries as described in section 2.8.4 according
to the scheme shown in Fig. 15.
The suppressor module must never be switched in the dry state as
there is a danger of blocking. Before every switching operation of the
suppressor module, the three suppressor units must have been
rinsed for at least ½ h with eluent, regeneration and rinsing solution.
The capacity of the suppressor units is exhausted after approx. 2 h.
With longer interruptions between the individual measurements, it is
recommended that the Prep MSM.smt system is started during the
pauses; this automatically switches the suppressor module further
every 20 min.
Maintenance
In the event of reduced capacity or high counter-pressure the suppres-
sor module must be regenerated (section 5.2.7), cleaned (section 5.2.8)
or exchanged (section 5.2.9).
5.1.6 Connections
All connections between injector, column and detector must be as short
as possible, have a low dead volume and be absolutely tight. The PEEK
capillary after the detector block must be free from constriction (the
measuring cell is tested to 5 MPa = 50 bar back pressure).