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English
Calibration
All Finnpipettes are factory calibrated and adjusted to give the volumes as specified with distilled
or deionized water. Normally, the pipettes do not need adjustment, but they are constructed to
permit recalibration and adjustment for liquids of different temperature and viscosity.
Device requirements and test conditions
An analytical balance must be used. The scale graduation value of the balance should be chosen
according to the selected test volume of the pipette:
Volume
readable
Precision
Uncertainty of
range
graduation
repeatability(s) measurement
and linearity
under 10 µl
0.00 1mg
0.001mg
0.002µl
10-100 µl
0.01 mg
0.02mg
0.02µl
above 100 µl
0.1 mg
0.2mg
0.2µl
If the uncertainty of measurement of the balance is known, this may be used instead of the
repeatability and linearity.
Test liquid: Water, distilled or deionized, “grade 3” water conforming ISO 3696. Tests are done in
a draft-free room at a constant (±0.5°C) temperature of water, pipette and air between 15°C to
30°C.
The relative humidity must be above 50%. Especially with volumes under 50µl the air humidity
should be as high as possible to reduce the effect of evaporation loss. Special accessories, such
as the evaporation trap, are recommended.
Calibration Counter
By selecting MENU -> OPTIONS -> CALIBRATE -> COUNTER the number of pipetttings since last
calibration is shown on the display. The counter is reset to zero when calibration is performed.
Checking the calibration
The pipette is checked with the maximum volume (nominal volume) and with the minimum volume.
A new tip is first pre-wetted 3-5 times and a series of ten pipettings are done with both volumes.
A pipette is always adjusted for delivery (Ex) of the selected volume. Measuring volumes taken
from balance is not allowed.
Procedure:
1. Do 10 pipettings with the minimum volume.
2. Do 10 pipettings with the maximum volume.
3. Calculate the inaccuracy (A) and imprecision (cv) of both series.
4. Compare the results to the limits in the Table 1.
If the calculated results are within the selected limits, the adjustment of the pipette is correct.
TABLE1: Maximum permissible errors according ISO8655
Range
Volume
Inaccuracy
Imprecision
µl
µl
%
s.d. µl
cv%
1-10 µl
10
±0.120
±1.2
0.080
0.8
1
±0.120
±12
0.080
8.0
5-50 µl
50
±0.50
±1.0
0.20
0.4
5
±0.50
±10
0.20
4.0
10-100 µl
100
±0.80
±0.8
0.30
0.3
10
±0.80
±8.0
0.30
3.0
30-300 µl
300
±4.0
±1.3
1.5
0.5
30
±4.0
±13
1.5
5.0
100-1000 µl
1000
±8.0
±0.8
3.0
0.3
100
±8.0
±8.0
3.0
3.0
0,5-5 ml
5000
±40.0
±0.8
15.0
0.3
500
±40.0
±8.0
15.0
3.0
1-10 ml
10000
±60.0
±0.6
30.0
0.3
1000
±60.0
±6.0
30.0
3.0
