Metrohm 940 Professional IC Vario ONE/ChS/HPG - Manual (Page 68)

5.7 Notes on operating the high-pressure pump
￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭
60 ￭￭￭￭￭￭￭￭
940 Professional IC Vario ONE/ChS/HPG (2.940.1240)
Connecting the connecting tubing
1 ￭ Insert the clamping screws on the connector and screw them in
by hand.
￭ Tighten the clamping screws with the wrench.
5.7 Notes on operating the high-pressure pump
CAUTION
The pump head is filled ex works with methanol/ultrapure water. Ensure
that the eluent used is miscible with this solvent.
Keep the following recommendations in mind in order to protect the
high-pressure pump from damage as much as possible during operation:
￭ To protect the high-pressure pump from foreign particles, we rec-
ommend filtering the eluent through a filter with a pore size of 0.45
µm and aspirating it via an aspiration filter (6.2821.090).
￭ Ensure that no precipitates can form when changing the eluent. Salt
crystals between the piston and seal cause abrasive particles that can
find their way into the eluent. These lead to contaminated valves, an
increase in pressure and, in extreme cases, scratched pistons.
Immediately successive solutions must always be miscible. If the system
has to be rinsed with organic solvents, use several solvents with rising
or falling lipophilicity.
￭ In order to protect the pump seals, ensure that the pump is never
operated dry. Therefore ensure that the eluent supply is correctly con-
nected and that there is enough eluent in the eluent bottle each time
before turning on the pump.