Metrohm 930 Compact IC Flex Oven/SeS/PP/Deg - Manual (Page 75)

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5 Operation and maintenance
930 Compact IC Flex Oven/SeS/PP/Deg (2.930.2560)
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The composition of the eluent plays a critical role in chromatographic ana-
lysis:
Concentration An increase in the concentration generally leads
to shorter retention times and faster separation,
but also to a higher background conductivity sig-
nal.
pH pH changes lead to shifts in dissociation equili-
bria and thus to changes in retention times.
Organic solvents Adding organic solvents (such as methanol, ace-
tone or acetonitrile) to a watery eluent generally
speeds up lipophilic ions.
5.5.2 Changing the eluent
Ensure that no precipitates can form when changing the eluent. Immedi-
ately successive solutions must be miscible. If the system has to be rinsed
with organic solvents, several solvents with rising or falling lipophilicity
must be used.
NOTE
To change the eluent, remove the separation column and connect the
capillaries using a coupling (6.2744.040) and two pressure screws
(6.2744.070).
5.6 Servicing the eluent degasser
The pieces of connection tubing are connected to the eluent degasser
with clamping screws.
Proceed as follows if you have to loosen and reconnect the connection
tubing at the eluent degasser:
Accessories For this step you need the following accessories:
You can find these parts in the accessory kit: Vario/Flex Basic (6.5000.000)
￭ Wrench (6.2621.050)
Loosening the connecting tubing
1 ￭ Loosen the clamping screws with the wrench.
￭ Unscrew the clamping screws by hand and pull them out of the
connector.