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to the direction diminishing counter readings to the
required volume. Before achieving the required volume
slowly rotate the knob and observe carefully diminishing
reading to avoid accidentally passing the setting value.
• If the desired volume is higher than set volume shown by
the counter, the operator should turn the pipetting push-
button (Fig. 1A2) or the adjustment knob (Fig. 1B) incre-
asing the value until the lower figure wheel comes 1/3 of
a turn beyond the required setting and then slowly back-
ward until the setting reaches the desired volume. Make
sure not to pass the setting value.
If the knob is accidentally turned too far, the process
must be repeated. The desired volume must always be
set from the higher value in the order of decreasing value.
Following volume adjustment, set the locking ring into the
upper position, thus locking the knob and preventing
accidental volume change.
3 - ASPIRATING AND DISPENSING LIQUIDS
Place a tip on the shaft of the pipette. See Section 6 for
the appropriate tip. Press the tip on firmly using a slight
twisting motion. This will ensure an airtight seal.
Important: Never aspirate liquids into the BIOPETTE
PLUS without a tip attached.
Aspiration
Press the pushbutton to the first positive stop, (Fig. 2A).
Holding the pipette vertically, immerse the tip into the
sample liquid. The depth to which the tip is immersed in
the sample liquid depends on the model.
Model
BPP2
BPP10
BPP20, BPP100
BPP200, BPP1000
BPP5000
BPP10000
Release the pushbutton slowly and smoothly to aspirate
the sample, (Fig. 2B). Wait one second and then with-
draw the tip from the liquid. When the pipette tip is
immersed not as deeply as the recommended depth or
when the pipetting pushbutton is rapidly released air
may enter the disposable tip.
5
Immersion depth (mm)
≤ 1
≤ 1
2 – 3
2 – 4
3 – 6
5 – 7
Avoid touching the orifice of the tip.
Dispensing
• Place the end of the tip against the inside wall of the
vessel at an angle of 10 to 40 degrees.
• Press the pushbutton smoothly to the first stop, (Fig. 2C).
Wait one second.
• Press the pushbutton to the second stop to expel any
remaining liquid, (Fig. 2D).
• Keeping the pushbutton depressed to the very end,
remove the pipette by drawing the tip against the inside
surface of the receiving vessel.
• Release the pushbutton to its starting position, (Fig. 2E).
• Eject the tip by pressing the tip ejector button, (Fig. 2F).
Remember to change the tip whenever a different liquid
is to be sampled or the volume setting is changed.
Filters
A replaceable filter installed in a seat in the bottom part of
the shaft is used in 5000 μl and 10000 μl pipettes (Fig. 3L).
The filter prevents the aspirated liquid from entering into
the shaft and thus from polluting the inside of the shaft
and the piston. Using the filter is especially important
when aspirating and dispensing large volumes of liquid.
If the filter becomes wet during liquid aspiration it should
be replaced with a new one.
4 - PRE-RINSING
When pipetting liquids of higher viscosity or lower sur-
face tension than water (e.g. sera or organic solvents),
a film of liquid is formed on the inside wall of the pipette
tip. This film can create an error. Since the film remains
relatively constant in successive pipetting operations
with the same tip, this error can be avoided by forming
the film before transferring the first sample. This is done by
aspirating a sample and dispensing it back into the same
vessel. Since the film is already formed, all of the following
samples will have better accuracy and repeatability.
This pre-rinsing operation should be repeated when the
volume to be aspirated is changed or when a new tip is
used.
6
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