Choosing A Draw Rate For The Sample Syringe; Choosing The Needle-Placement Setting - Waters ACQUITY UPLC Overview And Maintenance Manual

2.25 Choosing a draw rate for the sample syringe

The optimal draw rate for the syringe plunger depends on the volume and viscosity of the sample
and the specified cycle time. Default draw rates depend on the needle size:
• 15 µL needle: 30 µL/min
• 30 µL needle: 120 µL/min
You can also specify the draw rate, in microliters per minutes, if desired.
Table 2–6: Maximum syringe draw rates
Solvent type
50:50 methanol/water
100% water
100% acetonitrile
100% dimethyl sulfoxide (DMSO)
Increasing the syringe draw rate reduces the time required to aspirate sample. Note that
increasing the draw rate too much results in poor area and height reproducibility. When
increasing the draw rate, be sure to confirm the continued acceptability of the method.

2.26 Choosing the needle-placement setting

Needle placement is the vertical distance from the tip of the sample needle to the bottom of the
sample vial. The default setting for the needle placement prevents the needle from reaching the
bottom of the vial.
Notice:
that the needle is calibrated, and use the appropriate needle-placement setting for your
sample plates or vials.
See also:
For information about calibrating the needle, see
You can change the default needle-placement setting in the software in two places: on the
Dilution tab of the Sample Manager instrument method editor and in the Advanced Settings
dialog box.
Table 2–7: Default needle-placement settings
Plate type
48-vial
All other plates
To avoid damaging the needle, follow the guidelines in this section, ensure
June 11, 2019, 715005051 Rev. D
15-µL needle
30 µL/min
55 µL/min
150 µL/min
25 µL/min
Calibrating the
Default
4.0 mm (automatic)
2.0 mm
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30-µL needle
120 µL/min
230 µL/min
500 µL/min
100 µL/min
needle.