Adjusting Stroke Volume; Automatic Shut-Down - Agilent Technologies 1100 Series User Manual

Using the Pump

Adjusting Stroke Volume

When the compressibility setting is set to Off, the pump makes no compensation for
the compressibility of the mobile phase.
For each particular compressibility value, the piston stroke (distance piston moves)
and the speed at which the piston moves are adjusted accordingly, compensating for
the solvent compressibility. For a mixture of solvents we recommend that you
choose the compressibility value of the solvent that is present in the highest amount.
Adjusting Stroke Volume
The stroke volume defines the volume of mobile phase which is displaced by one
stroke of pump piston 1. You can set the stroke volume to AUTO (automatic) or a
value between 20 and 100 µl. When the stroke is set to AUTO, the pump uses large
strokes at high flow and shorter strokes at low flow rate. This can improve the
mixing performance and gradient linearity by reducing the size of the solvent
packets to be mixed.
The stroke volume can be accessed by using the Settings button [F1] in the Analysis
screen, selecting the pump and then pressing More ...
The amplitude of the pressure pulsation is directly proportional to the stroke
volume. Decreasing the stroke volume decreases the pulsation amplitude, giving a
better signal-to-noise ratio with flow-sensitive detectors. To maintain the flow, the
pumping frequency is increased, increasing the frequency of the pressure pulsation.
Increasing the pump frequency gives better peak area reproducibility at low flow
rates.

Automatic Shut-down

At the end of a sequence you can set the pump to be automatically turned off using
the Sequence End Actions button [F1] in the Sequence screen. You can turn off the
pump completely or load a specific shut-down method.
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