Dionex As - Sampling Needle Arm

2 • Description
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2.3.2 Sampling Needle Arm
During operation, the sampling needle arm moves the sample needle
along X-, Y-, and Z-axes. The sample tray remains stationary throughout
the sampling process.
To sample from a vial or well plate, the arm moves to the specified
position in the tray and lowers the needle into the vial or well. The
sampling needle pierces the vial cap or well plate cover to allow fluid to
be drawn or delivered. When sampling is complete, the arm raises the
needle out of the vial or well. When running a schedule of injections, vials
or wells can be sampled in any order.
The needle height (the distance from the tip of the needle to the bottom of
the vial or well) can be adjusted, allowing operations such as liquid-liquid
extraction.You can set the needle height in a Chromeleon or Chromeleon
Xpress program (see Section 3.2.2
) or in a front panel program (see
page 292
).
NOTE Changing the needle height is not recommended
when sampling from a micro-well well plate,
because the well depth is shallow. You can adjust the
needle height in a deep-well well plate as required,
provided the needle remains submerged in sample.
This ensures accurate sample aspiration.
During a flush operation, the sampling needle arm delivers flush fluid to
the flush port (see Figure 2-7
).
The autosampler door must remain closed during operation. If you
open the door during operation, the sampling arm stops immediately.
If a schedule is running, it is ended. To safely open the door during a
schedule, press the Door button. See Section 3.9 for details.