Checking The Volume - BRAND Transferpette-8 electronic Operating Manual

6 Checking the volume

We recommend testing the device every 3 to 12 months, depending on the level of use. However, the
testing cycle can be adapted to meet individual requirements. Gravimetric volume testing of the
pipette is carried out according to the following steps and complies with DIN EN ISO 8655, Part 6.
1. Setting the nominal volume
a.
Set the maximum specified instrument volume (for procedure, see Pipetting, p. 56).
2. Conditioning the pipette
a.
Condition the pipette before testing by aspirating and dispensing the test liquid (distilled water)
with a pipette tip five times.
3. Performing the test
In accordance with DIN EN ISO 8655-2, a tip change is recommended after each individual measure-
ment. An exception to this rule can be made, according to DAkkS guideline DKD-R8-1.
a.
Aspirate the test liquid and pipette into the weighing vessel.
Each individual channel must be inspected separately.
b.
Weigh the pipetted amount with an analysis scale. (refer to the operating manual of the balance
manufacturer.)
c.
Calculate the pipetted volume. In doing so, take into account the temperature of the test liquid.
d.
At least 10 pipetting series and weighings in 3 volume ranges (100 %, 50 %, 10 %) are recom-
mended.
Calculation (for nominal volume)
x = weighing results
i
Z = Correction factor (e.g. 1.0029 µl/mg at 20°C, 1013 hPa)
Mean:
Coefficient of variation*:
Transferpette® -8/-12 electronic 997200
NOTICE
NOTICE
n = number of weighings
Mean volume:
Standard deviation*:
6 Checking the volume
V = nominal volume
0
Accuracy*:
Operating manual
67