Fisher Finnpipette Novus Instrucciones De Uso página 11

3. Select two points and confirm with OK. The target max. and target min. volumes are shown
on the display.
4. Do the pipetting series with both max. and min. volumes.
5. Calculate the actual results.
6. Repeat steps 1. to 3.
7. Press EDIT and change the actual max. volume with the SCROLLKEY and accept with OK.
8. Change the actual min. volume with the SCROLLKEY and accept with OK.
9. A text SAVE? appears on the display.
10. Accept with YES
11. The calibration is changed.
One point calibration
The one point calibration can be used if a single specific volume must be calibrated. The
calibration volume can be selected from the entire volume range. Note that the accuracy of
other volumes changes also and the performance for other volumes cannot be assured.
1. Do the pipetting series with calibration volume.
2. Calculate the results.
3. Press MENU and select options with SCROLLKEY and accept with OK.
4. Select CALIBRATE and press OK.
5. Select one point and confirm with OK. The calibration volume is shown on the display.
6. Press EDIT and change the calibration volume with the SCROLLKEY and accept with OK.
7. Change the actual volume with the SCROLLKEY and accept with OK.
8. A text SAVE? appears on the display.
9. Accept with YES
10. The calibration is changed.
Formulas for calculating results
Conversion of mass to volume
V = (w + e) x Z
Evaporation loss can be significant with low volumes. To determine mass loss, dispense water
to the weighing vessel, note the reading and start a stopwatch. See how much the reading
decreases during 30 seconds (e.g. 6mg = 0.2mg/s).
Compare this to the pipetting time from tareing to reading. Typically pipetting time might be 10
seconds and the mass loss is 2 mg (10s x 0.2mg/s) in this example. If an evaporation trap or lid
on the vessel is used the correction of evaporation is usually unnecessary.
The factor Z is for converting the weight of the water to volume at test temperature and
pressure. A typical value is 1.0032µl/mg at 22°C and 95 kPa. See the conversion table on page 59.
Accuracy (systematic error)
Accuracy is the difference between the dispensed volume and the selected volume of a pipette.
A = accuracy
A = V - V
0
V = mean volume
V = nominal volume
0
Accuracy can be expressed as a relative value: A% = 100% x A / V
Precision (random error)
Precision refers to the repeatability of the pipettings. It is expressed as standard deviation (s)
or coefficient of variation (cv)
n
S
( V - V
S
=
i
i=1
n 1
-
Standard deviation can be expressed as a relative value (CV) CV = 100% x S / V
V = volume (µl)
w = weight (mg)
e = evaporation loss (mg)
Z = conversion factor for mg/µl conversion
s = standards deviation
)
2
v = mean volume
n = number of measurements
0
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