A&D Weighing MPA-1200 - Manual (Page 30)

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9-8 Total discharge function
Pressing and holding the Operation key expels all of the liquid remaining in the
tip. This function is useful when, for example, you want to terminate the operation
halfway through multiple dispensing.
Continuing to hold the Operation key down after this turns the pipette power off.
9-9 “Dispensing correction function” for multiple dispensing
The electronic pipette aspirates and dispenses a liquid by moving the internal piston
up and down using motor. Since movement of motor and piston reverses when the
operation switches from aspirating to dispensing, an error in dispensing volume due to
backlash will occur. To correct this error, the MPA series is equipped with the
“dispensing correction function” (Patent pending) for multiple dispensing, which
automatically discharges a small amount of sample before delivery. This ensures the
piston is always set in the descending direction when dispensing starts, keeping the
margin of error to a minimum.
10. PIPETTING FOR ACCURATE DISPENSING
□
When performing aspiration, if the tip is immersed
too deeply into the sample liquid, an amount larger
than the selected dispensing volume may be
delivered, as excess liquid attaches the outside of
the tip. Ideally, for aspiration, the tip should be dipped
into the liquid to a depth of 2 to 3 mm.
The pipette is designed to correctly perform
aspiration when it is in the vertical position.
Therefore, hold the pipette as vertically as possible
when aspirating.
□ When replacing the tip, pre-rinse the tip with the
necessary dispensing volume setting. The reverse
operation is recommended for a sample liquid that
tends to linger in the tip.
□
When dispensing the sample, touch the tip at a 30°
to 40°angle to the wall of the receiving vessel.
2 to 3mm
30°to 45°