Waters 2707, Руководство оператора

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3-8 Maintaining the Autosampler
Result:
The sample needle returns to the home position.
10. Clean the new needle by clicking “Wash needle” from the Control menu
of the 2707 Console.
11. If needed, use the Adjust Needle Position function to finetune the x-y
injection position. See the following “Adjusting needle position” section.
Adjusting needle position
The air needle comprises the outer shell of the needle assembly. Its tip
extends downward, but not as low as the tip of the sample needle. The air
needle supports the needle wash process and mechanically supports the
sample needle. When you enable the pressurize vial feature, it delivers
pressurized air.
The instrument’s needle and tray mechanism is preadjusted at the factory to
work with any of the supported well plates or vial holders. When using plates
or holders whose dimensions do not comply with ANSI dimensions or other
geometrical offsets, use the Adjust Needle function.
Maintaining air needles
The instrument uses six air needles of varying length to accommodate
different plate heights in the instrument. An air needle is available for every
well/vial plate. The needles vary in 6-mm intervals; the needle holder allows
for an extra 6-mm variation in needle height.
Ideally, the end of the air needle pierces the vial cap or septum during sample
aspiration, but it should not extend far enough to contact the liquid sample.
The standard-length air needle works well in most cases.
Examining the standard air needle
The standard air needle, which is 62 mm long, accommodates a wide range of
high and low plates. The accompanying figures show the needle’s puncturing
depths.
Caution:
To prevent the needle from touching the bottoms of vials
when using trays with 12 or 48 vials, make sure the needle height
setting is > 2 mm.