Metrohm 709 IC Pump - Manual (Page 33)

4.1 Practical notes
709 IC Pump
25
4 Notes – Maintenance – Faults
4.1 Practical notes
4.1.1 Protection against foreign particles
To protect the column against foreign particles which could have an
adverse influence on the separation efficiency, we advise you to subject
both the eluents and all samples to microfiltration (0.45 µ m filter) and
to siphon the eluent through the 6.2821.090 Aspirating filter.
To avoid contamination by abrasive particles arising from piston seals
of the 709 IC Pump, it is advantageous to install an in-line filter be-
tween the pump and the 733 IC Separation Center. We recommend to
use either the 6.2821.100 Filter unit PEEK for the standard operation
with PEEK capillaries (see section 2.3.5) or the 6.2821.000 Filter unit
Manufit for the operation in the pressure range > 25.0 MPa
(> 250 bar) with steel capillaries (option, see section 2.3.6).
4.1.2 Pulsation dampener
To protect the column material against pressure shocks caused by in-
jection we recommend to use a pulsation dampener between the 709
IC Pump and the 733 IC Separation Center. The optional 6.2620.150
Pulsation dampener MF (see section 2.3.4) is eminently suitable for
this purpose.
4.1.3 Eluents
Treatment
For the preparation of the eluents one should use chemicals of a purity
degree of at least "p.a.". For dilution please use only high purity water.
Fresh eluents should always be microfiltered (0.45
µ m filter) and de-
gassed (with N
2
, He or vacuum). The eluent should be continuously
stirred with a magnetic stirrer, particularly when the recycling proce-
dure is employed or when alkaline eluents are used. For alkaline elu-
ents and eluents with low buffering capacity one should preferably use
CO
2
absorbers.
The supply vessel containing the eluent must be closed as tightly as
possible to avoid excessive evaporation. This is primarily important with
eluents containing organic solvents (e.g. acetone), the evaporation of
which can lead to drifts in the long term. If work is performed in a very
sensitive range, even if one drop of condensate falls back in the eluent
this can cause a noticeable change in the background conductivity.