Metrohm 871 Advanced Bioscan - Manual (Page 32)

4 Notes - Maintenance - Faults
871 Advanced Bioscan / Instructions for Use 8.871.1003
24
Contaminated valves are cleaned by rinsing with water or organic sol-
vents. When the cleaned valves are reinstalled, you must ensure that
the flow direction is correct.
in accordance with
nding maintenance
s for Use.
the cause of abrasive
taminated
ratched pistons. It is
thus essential to ensure that no precipitates can appear (see also
section 4.2.3).
4.2.3 Eluents
ofiltered (0.45 µ m filter) and de-
gassed (with N , He or by using an 837 Eluent Degaser). For alkaline
low buffering capacity one should preferably
on.
• pH: pH alterations lead to shifts in the dissociation
Eluent change
W
c
miscible. If the system has to be rinsed with an organic solution, several
solvents with increasing or decreasing lipophilic character may possibly
4.2.4 Connections
All connections between injector, column and detector must be as short
e and be absolutely tight.
The replacement of piston seals has to be done
the pump manufacturer’s directions. The correspo
work for the 818 IC Pump is described in the 818 Instruction
Salt crystals between the piston and the seal are
particles, which can enter the eluent. These lead to con
valves, pressure rise and in extreme cases to sc
Treatment
For the preparation of the eluents only chemicals of a purity degree of
at least "p.a." should be used. For diluting please use only high purity
water.
Fresh eluents should always be micr
2
eluents and eluents with
use a CO
2
absorber (e.g. the absorber supplied with the optional
6.5324.000 Bottle rack).
The supply vessel containing the eluent must be closed as tightly as
possible to avoid excessive evaporation.
Influence of various parameters
• Concentration: An increase in the concentration usually leads
to shorter retention times and quicker separa-
ti
equilibrium and thus to changes in the reten-
tion times.
hen the eluent is changed, it must be ensured that no precipitates
an be formed. Solutions used in direct succession must therefore be
have to be used (e.g. water ↔ acetone ↔ chloroform).
as possible, have a low volum