SERVICE AND CALIBRATION - Pretech Instruments

SERVICE AND CALIBRATION
A pipette is to liquids what a laboratory balance is to solids.
Like balances and other precision instruments, pipettes should be periodically inspected, cleaned,
maintained and calibrated so that they will perform within the specifications established by the
manufacturer.
Accurate
but not precise
Precise
but not accurate
Accurate
and precise
Maintenance and daily care
A pipette is a precision instrument that sometimes is used for volumes as low as 0,1µl. It is therefore
important that you treat your pipette in a correct way. A recommendation is that you make an
overlook and a performance check of your Pipetman every 6 months. This to ensure that accuracy and
precision is up to specifications
Check the records
GLP (Good Laboratory Practice) laboratories must keep detailed
records of every step in the analytical procedure. When a
pipette is used, the laboratory must be able to produce
information such as identification number, history of the
pipette, specifications, control method and environmental
conditions.
All Gilson pipettes can easily be identified by the engraved
serial number. The first letter represents the year, the number
is the individual production number and the last letter
corresponds to the month of manufacture.
Check Pipetting functions
Make a visual check to see that the Operating Rod is not bent or corroded, that the Volumeter works in a correct way,
check the function of the Tip Ejector system and also take a close look at the tip holder with a magnifying glass to see that
there are no scratches or chemical damages.
Next step is to check all functions of you Pipetman. Does the volume setting move smooth? Go through the entire range!
Min. and max. settings should correspond to the pipettes normal volume range. Then fit a tip onto the pipette and depress
the tip-ejector button to test the function of the tip ejection system.

Leak test
To make sure that your Pipetman is in good condition it is recommended to do a
leak test. Fit a Gilson tip and set the volume at maximum. Aspirate water and
maintain liquid 20 seconds in the tip. Observe if a drop or leak appears at the
orifice of the tip. For P2-P200 re-immerse in the test liquid. The fluid level should
not descend. This test is recommended to be performed daily. If there is a leak you
need to exchange the O-ring and Teflon Seal and perhaps the Tip Holder. This you can do yourself by
following the instructions under Disassemble below.
Disassemble the pipette
If the pipette has a leak or does not work properly you might need to disassemble it. Simply pull off
the tip ejector. Then unscrew the connecting nut and separate the handle from the bottom part.
Remove the piston from the tip holder. Now check the piston. Is it scratched or corroded? Also check
the seal and o-ring. Are they damaged or maybe worn out? Same thing with the tip holder. Check the
lower end for scratches and the internal for dirt. Change all parts that is damaged or worn out. If the
piston is changed, the pipette needs recalibration. When you reassemble the pipette make sure to
respect the correct order of the parts. The piston seal should always be positioned before the o-ring.
Return to Pretech for service
Pretech has a fully equipped calibration laboratory with balances controlled by SWEDAC. All personnel
handling your pipettes are trained by Gilson. The environmental parameters such as temperature,
humidity and air pressure is logged 24 hours a day. These values are used to estimate evaporation
and to convert readings as weight (mg) to volume (µl).
Standard service and repair or... cost saving = Service contract
We perform full service, calibration and adjustment on all Gilson pipettes as described later. We also
offer a control of your pipette. This means that we verify the status of the pipette and if it corresponds
to Gilson specifications or not.
For customer that want to have regular service, we recommend to sign up for a service contract. This
is a convenient way of having problem-free pipetting year after year. All pipettes calibrated under a
contract are washed and decontaminated. New tip holder, piston seal and O-ring are included in the
price. Signing up for a contract saves you 25% compared with regular service. Contact us and we will
tell you more about the advantages of signing up for a contract for Gilson pipettes. We will return your
pipettes with a minimum of delay. From door to door normal delivery time is not more than one week.
Standard service
You can at any time send us your pipettes for service and calibration. You can send them one by one
or a few together as it suits you. Our personnel will take care of them in order of arrival and perform
the same service as described above.
Certificate of calibration
With each serviced and calibrated pipette follows a calibration certificate that is set up according to
GLP. All measurements, temperature, humidity and air pressure is displayed. For historical records
earlier calibration values are also written on the certificate.

Decontamination and repair
All pipettes are disassembled, washed, decontaminated and then dried in an oven for 4 hours. After
that the pipettes are left overnight at room temperature for stabilisation. We make control of all
mechanical parts and change them if needed. Tip holder, piston seal and o-ring are always exchanged.
All mechanical functions such as piston movement, tip ejector mechanism and counter are controlled.
After assembly the pipettes are placed in a carrousel stand in the calibration room and will rest for at
least 30 minutes. This means that the pipette are mechanically stabilized before the actual calibration
will begin.
Calibration
According to Gilson calibration procedure all pipettes are checked by five measurements on low (min.)
and high (max.) volume. If the pipette is outside of Gilson specifications, it needs to be re-calibrated
by mechanical adjustment. Five new measurements are then performed again. This to verify that the
pipette now corresponds to Gilson specifications.
Next step in the procedure is to verify the pipettes maximum volume.
If the pipette still falls outside the allowed tolerance, it needs to be re-calibrated and adjusted again.
This procedure is repeated until the pipette corresponds to Gilson specification.
Perform service by yourself
If you want to do more than change tip holder and seals yourself Pretech offer the following tools and
services:
Calibration tool
Training at customers site
Swedish pipetting guide with drawings
Gilson guide to pipetting
All spare parts in stock for fast delivery
PRETECH Instruments
Mikael Hollmark
Email: mikael.hollmark@pretech.nu
Tel: 08 - 92 00 09