Maintenance - Thermo Scientific Finnpipette F3 Guide D'utilisation

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 52.
Inaccuracy (systematic error)
Inaccuracy is the difference between the dispensed volume and the selected volume of a pipette.
A = V - V A = inaccuracy
0
V = mean volume
V
0
Inaccuracy can be expressed as a relative value: A% = 100% x A / V
Imprecision (random error)
Imprecision refers to the repeatability of the pipettings. It is expressed as standard deviation (s)
or coefficient of variation (cv)
Standard deviation can be expressed as a relative value (CV) CV = 100% x S / V
When the Finnpipette F3 is not in use, make sure it is stored in an upright position. We
recommend a Finnpipette stand for this purpose.
The part # refer to exploded views beginning at page 53.
Short-term service
The pipette should be checked at the beginning of each day for dust and dirt on the outside
surfaces of the pipette.
Particular attention should be paid to the tip cone. No other solvents except
70 % ethanol should be used to clean the pipette.
Long-term maintenance
Annual pipette usage varies significantly among laboratories, and the
types of substances being aspirated and dispensed also vary tremendously
among laboratories. In order to maintain proper care of the pipette, it is the
laboratory's responsibility to develop a proper maintenance program that
meets its specific needs and requirements.
The servicing procedure starts with the disassembly of the pipette.
1-1000 µl pipettes
1. Press the tip ejector.
2. Rotate the tip ejector 11 counterclockwise and pull it out.
3. Turn out the tip cone counterclockwise with the service tool.
4. Pull out the piston and other parts. Push out with piston
the rest of the piston assembly. Then turn the tip cone
upside down and tap all parts from tip cone. Remember
keep all parts in order on table for reassembly.
5. Clean the piston, the piston spring and the O-rings with a dry
napless cloth.
V = volume (µl)
w = weight (mg)
e = evaporation loss (mg)
Z = conversion factor for µl/mg conversion
= nominal volume
s = standards deviation
v = mean volume
n = number of measurements

Maintenance

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