5 -DENSE AND VISCOUS LIQUIDS
The
BIOPETTE PLUS
specifications of accuracy and pre-
cision are based on pipetting distilled water. The handling
of liquids with physical qualities of density, viscosity and
surface tension differing extremely from water may need
a gravimetrically checked compensation of the volume
setting. Normally the degree of error resulting from heavy
or viscous liquids is negligible if the pipetting is done
slowly and carefully. It is most important to give the liquids
some time to follow the change of pressure by holding
the pipette tip in its position for at least 2 sec. after the
aspiration and the blow out stroke.
If in extreme cases this method of operation does not
result in accurate values, a compensation could be
achieved as follows:
Weigh the liquid pipetted when the
BIOPETTE PLUS
is set
to the nominal value. Then calculate the offset from the
nominal value:
Corr: val. = 2 x nom. val. -
- weight of the sample
- density of liquid
Check this operation once again and correct if neces-
sary. Note the corrected value for further pipetting the
same kind of liquid.
6 - LABNET PIPETTE TIPS
Labnet
tips are made from high performance polypropy-
lene and their quality guarantees the precision and accu-
racy associated with the
BIOPETTE PLUS
. Strict control
is maintained throughout the manufacturing process to
ensure the highest quality.
The accuracy and precision figures for the
BIOPETTE
PLUS
are only guaranteed when
Labnet
tips are used.
The use of inferior quality tips will seriously degrade the
performance of the
BIOPETTE PLUS
.
Tips 10
These tips are used for volumes between 0.1 μl and 10 μl.
They are used with the BPP2 and the BPP10 models.
Tips 200
These tips are used for volumes between 2 μl and 200 μl.
They are used with the BPP20, BPP100 and the BPP200
models, which are equipped with the yellow label on the
pushbutton.
γ
m
m
-
γ
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Tips 1000
These tips are used for volumes between 100 μl and
1000 μl. They are used with the BPP1000 models, which
are equipped with the blue label on the pushbutton.
Tips 5000
These tips are used for volumes between 1000 μl and
5000 μl. They are used with the BPP5000 models.
Tips 10000
These tips are used for volumes between 1000 and
10000
μ
l. They are used with the BPP10000 models.
7 - RECOMMENDATIONS
Observing the following recommendations will ensure
maximum possible accuracy and precision of liquid sam-
pling.
• Make sure to operate the
BIOPETTE PLUS
slowly and
smoothly.
• The depth of immersion in the sample liquid should be
the minimum necessary and should remain constant
during aspiration.
• The
BIOPETTE PLUS
should be held in a vertical posi-
tion.
• Change the tip when volume setting is changed or when
a different liquid is to be aspirated.
• Change the tip if a droplet remains on the end of the tip
from the previous pipetting operation.
• Each new tip should be pre-rinsed with the liquid to be
pipetted.
• Liquid should never enter the
BIOPETTE PLUS
shaft. To
prevent this:
- Press and release the pushbutton slowly and smoothly.
- Never turn the pipette upside down.
- Never lay the pipette on its side when there is liquid in
the tip.
• Never force the volume setting beyond its recommend-
ed limits.
• When pipetting liquids with temperatures different from
the ambient temperature, it is recommended to pre-
rinse the tip several times before use.
• Do not pipette liquids with temperatures above 70°C.
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