Operation; Pre-Rinsing - VWR Signature EHP Manual Del Usuario

VWR EHP-03-2008 13 9-04-08
To attain the maximum accuracy, set volume must be
approached from a higher value. If the desired value is
lower than the previous value, simply use the knob in the
pushbutton (Fig. 1A2) or the adjustment knob
(Fig. 1B) to adjust the value down to 1/3 turn above the
required setting. If the desired value is higher than the
previous value, use the knob in the pushbutton or the
adjustment knob to adjust the value to 1/3 turn above the
required value. The setting should then be performed in
the following manner:
With the volume set to 1/3 above the required setting,
slowly turn the pipetting pushbutton knob or the adjustment
knob to the required volume.
If the knob is accidentally turned too far, ie is set lower
than the required value, the process must be repeated.
The approach to the set volume must always be made 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 - OPERATION

Place a tip on the shaft of the pipettor. See Section 6 for
the appropriate tip. Press the tip on firmly using a slight
twisting motion to ensure a positive, airtight seal.
Note: Never handle a liquid with VWR EHP Pipettor,
which has not been fitted with a tip.
Aspiration
Press the pushbutton to the first positive stop, Fig. 2A.
Holding the pipettor 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
VWR VE2/V2 und VWR VE10/V10
VWR VE20/V20, VWR VE50/V50
and VWR VE100/V100
VWR VE200/V200, VWR VE250/V250
and VWR VE1000/V1000
VWR VE5000/V5000
VWR VE10000/V10000
Release the pushbutton slowly and smoothly to aspirate
the sample, Fig. 2B. Wait one second and then withdraw
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Immersion depth (mm)
1 mm
2 - 3 mm
2 - 4 mm
3 - 6 mm
5 - 7 mm
the tip from the liquid. Wipe any droplets away from the
outside of the tip using a medical wipe.
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 pressed to the end, remove
the pipettor by drawing the tip along the inside surface
of the vessel.
• Release the pushbutton, Fig. 2E.
• Eject the tip by pressing the tip ejector button, Fig. 2F.
It is only necessary to change the tip if a different liquid
is being sampled or if the volumeter 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 pipettors
(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 which have a viscosity and density
different than water, for example organic solvents, a film
of liquid is formed on the inside wall of the pipettor 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.
ENGLISH
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