Introduction to the Agilent 7100 Capillary Electrophoresis System

5 Using the Agilent 7100 Capillary Electrophoresis System
Capillary Electrophoresis, CE
Wash Inlet Electrode (New Command to Avoid Carry-over in Critical
Applications)
During precondition and postconditioning a command for emptying the space
between capillary and electrode can be executed. The command is dedicated
for applications with aqueous buffers and consists of application of slight
vacuum to the inlet vial while lowering the inlet vial. This leads to opening of
an internal sealing of the electrode and an airstream inside the wash vial at
the inlet lift. Liquid stored in the space between capillary and electrode is
removed. It is recommended to perform this prior to a flush step with run
buffer in case of carry-over critical applications. The wash inlet electrode
command is not available for the outlet electrode. At the inlet lift a dedicated
wash vial should be present. Using the Wash Inlet Electrode commands leads
to injection of a small volume on the outlet side (equaling approximately
50 mbar x 3 s for a 50 µm capillary). Therefore, position at the outlet side a
vial with run buffer or any other suitable run buffer vial. Empty vials at the
outlet lead to air in the capillaries which needs to be flushed out again.
NOTE
Usage of short electrodes (part number G7100-60033) in combination with pressure
injections also reduces this type of take over greatly (insert #reference to injection
section). Short electrodes are shorter by 5 mm, sample is filled only at low level and so the
electrode does not touch the sample.
102 Agilent 7100 Capillary Electrophoresis System User Manual