Adjustment - Thermo Fisher Scientific Finnpipette FOCUS 4600100 Guide D'utilisation

Volume
µl
1
2
5
10
20
25
50
100
200
250
500
1000
2 ml
3 ml
5 ml
10 ml

Adjustment

Adjustment is done with the service tool.
1. Place the service tool into the openings of the
calibration nut at the top of the handle. Keep fine
volume adjustment in place.
2. Turn the service tool clockwise to increase, or
counterclockwise to decrease the volume.
3. After adjustment check the calibration according
to the instructions above.
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. 6 mg = 0.2 mg/s).
Compare this to the pipetting time from taring to reading. Typically pipetting time might be
10 seconds and the mass loss is 2 mg (10 s x 0.2 mg/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 1.0032 µl/mg at 22°C and 95 kPa. See the conversion table on
page 47.
Inaccuracy (systematic error)
Inaccuracy is the difference between the dispensed volume and the selected volume of a pipette.
A
A = V - V
0
V
V
0
Inaccuracy can be expressed as a relative value:
A% = 100% x A / V
0
Imprecision (random error)
Imprecision refers to the repeatability of the pipettings. It is expressed as standard deviation
(s) or coefficient of variation (cv)
Inaccuracy
µl %
±0.04 ±4.0
±0.05 ±2.5
±0.07 ±1.4
±0.09 ±0.9
±0.12 ±0.6
±0.15 ±0.6
±0.3 ±0.6
±0.4 ±0.4
±0.8 ±0.4
±1.0 ±0.4
±1.5 ±0.3
±3.0 ±0.3
±6.0 ±0.3
±9.0 ±0.3
±15.0 ±0.3
±30.0 ±0.3
V = volume (µl)
w = weight (mg)
e = evaporation loss (mg)
Z = conversion factor for mg/µl conversion
= inaccuracy
= mean volume
= nominal volume
8
Imprecision
s.d.µl cv%
0.04 4.0
0.04 2.0
0.07 1.4
0.08 0.8
0.10 0.5
0.13 0.5
0.2 0.4
0.3 0.3
0.6 0.3
0.8 0.3
1.5 0.3
0.3 0.3
4.0 0.2
6.0 0.2
10.0 0.2
20.0 0.2