Pre-Rinsing; Dense And Viscous Liquids; Htl Pipette Tips; Recommendations - HTL LABMATE pro LMP2 Manual De Instrucciones

4 - PRE-RINSING

When pipetting liquids of higher viscosity or lo wer surface
tension than water (e.g. sera or or ga nic 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 rela-
tively 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 follow-
ing samples will have better accuracy and repeatability.
This pre-rinsing operation should be repeated when the
vo lume to be aspirated is changed or when a new tip is
used.

5 - DENSE AND VISCOUS LIQUIDS

The pipette specifications of accuracy and precision 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 gravi-
metrically checked compensation of the volume setting.
Normally the degree of error resulting from heavy or vis-
cous 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 pipette is set to the
nominal value. Then calculate the set-off from the nomi-
nal value:
Corr: val. = 2 x nom. val. -
- weight of the sample
m
γ
- 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 - HTL PIPETTE TIPS

HTL tips are made from high performance polypropylene
and their quality guarantees the precision and accuracy
associated with the pipette. Strict control is maintained
7
m
-
γ
throug hout the manufacturing process to ensure the
highest quality.
The accuracy and precision figures for the pipette are
only guaranteed when HTL tips are used. The use of
inferior quality tips will seriously degrade the perfor-
mance of the pipette.
Tips 10
These tips are used for volumes between 0.1 μl and 10 μl.
They are used with the LMP2 and LMP10 models.
Tips 200
These tips are used for volumes between 2 μl and 200 μl.
They are used with the LMP20, LMP50, LMP100 and
LMP200 models.
Tips 300
These tips are used for volumes between 50 μl and 250 μl.
They are used with the LMP250 models.
Tips 1000
These tips are used for volumes between 100 μl and
1000 μl. They are used with the LMP1000 models.
Tips 5000
These tips are used for volumes between 500 μl and
5000 μl. They are used with the LMP5000 models.
Tips 10000
These tips are used for volumes between 1000 μl and
10000 μl. They are used with the LMP10000 models,
which are equipped with a white pushbutton.

7 - RECOMMENDATIONS

Observing the following recommendations will ensure
maximal possible accuracy and precision of liquid sam-
pling.
• Make sure to operate the pipette slowly and smoothly.
• The depth of immersion in the sample liquid should be
the minimum necessary and should remain constant
during aspiration.
• The pipette should be held in a vertical position.
• Change the tip when volume setting is chan ged 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.
ENGLISH
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