Thermo Finnpipette BioControl Instrucciones De Uso página 8

STEPPER TECHNIQUE, (Fig.12)
In STEPPER mode, repeated dispensing of a selected unit volume is possible. There are three phases in stepper
pipetting: aspirate, dispense and blow-out.
1. Press the pipetting trigger to the second stop.
2. Holding the pipette in a vertical position, dip the tip ends in the liquid and release the pipetting trigger.
This action will fill the tips and start the stepper sequence.
Remove the tips from the liquid, touching them against the edge of the reservoir to remove excess
liquid.
3. Dispense the preset unit volume by gently pressing the trigger to the first stop. Remove the tips from
the liquid, sliding them along the wall of the vessel. Releasing the trigger to the ready position will not
move the piston.
4. Activate the next delivery by pressing the trigger to the first stop. The number of strokes left will be
displayed on screen.
5. After the last stroke, the words
dispense sequence has been completed. At this point, only the blow-out volume is left in the tips.
Activate blow-out by pressing the trigger to the second stop.
6. Release the trigger, and you are ready to start the next stepper sequence.
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 range readable graduation
under 10µl
10-100µl
above 100µl
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 20°C to 25°C. The
relative humidity must be above 55%. Especially with volumes under 50 µl 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.
CHECKING THE CALIBRATION
The pipette is checked with the maximum volume (nominal volume) and with the lower calibration volume,
see Table1. 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. If the calculated results are in the selected limits, the calibration of the pipette is
correct. With multichannel models use one of the middle channels to ensure an even load in the module.
Procedure:
1. Do 10 pipettings with the maximum volume.
2. Do 10 pipettings with the lower calibration
volume volume.
3. Calculate the accuracy (A) and precision (cv)
of both series.
4. Compare the results to the limits in the Table 1.
If the results are in the limits of Table 1, then the
calibration of the pipette is correct. Otherwise the
pipette must be adjusted and checked again.
STEPPER BLOW OUT
0.001mg
0.01mg
0.1mg
6
will appear on screen, indicating that the
Single Cannel modules
Range Increment Volume
µl
5-40µl 0.1µl 40
5
40-200µl 1µl 200
40
200-1000µl 1µl 1000
200
1-5 ml 0.01ml 5000
1000
2-10 ml 0.01ml 10000 ±50.0
2000
Accuracy Precision
µl % s.d. µl cv%
±0.240 ±0.6 0.120 0.3
±0.125 ±2.5 0.100 2.0
±1.20 ±0.6 0.60 0.3
±0.44 ±1.1 0.32 0.8
±6.0 ±0.6 2.0 0.2
±1.8 ±0.9 1.2 0.6
±25.0 ±0.5 10.0 0.2
±10.0 ±1.0 4.0 0.4
±0.5 20.0 0.2
±20.0 ±1.0 6.0 0.3