Gilson guide to pipetting - Emidio Albertini

3 .4
Follow the instructions for forward
or reverse mode pipetting
The choice of operating mode can
significantly affect the results of an
analysis.
Gilson pipettes are calibrated for forward mode
pipetting. Manufacturers should list all pertinent
modes of operation and specify for which mode
the instrument is calibrated.
The forward mode is the usual way of
pipetting with an air-displacement pipette
like Pipetman.
See page 26.
The forward mode for positive-displacement
pipettes like Microman eliminates the purge
stroke.
See page 30.
The reverse mode is only possible with
air-displacement pipettes. It is used for
solvents or slightly viscous liquids.
See page 28.
Wiping
If necessary (viscous liquids such as cream), wipe the
outside of the tip or the capillary with a clean medical
wipe. Do not touch the orifice. Choose a tissue which
is resistant, lint-free, and inert to acids and solvents.
Dispose of the tissue in a safe, hygienic manner.
Important
When working with high risk
specimens, do not wipe
the disposable part. Make sure fluid
depth penetration does not exceed
3 mm. Then touch-off from
the sidewall of the vessel.
Learning more
Pre-rinsing
Greater uniformity and
precision of dispensing are
usually obtained by providing
identical contact surfaces for
all aliquots. This is achieved
by pre-rinsing with the same
liquid that is being dispensed.
To pre-rinse, aspirate with the
tip and then dispense back
into the original reservoir or
to waste.
Q
AWhen should I pre-rinse
the tip?
Pre-rinsing should be
performed
• every time you change a tip
• every time you increase the
volume setting
Don’t forget to pre-rinse
• capillaries and pistons for
Microman
• DistriTips for Distriman
Chapter 3
25