BRAND Transferpette-8 Instrucciones De Manejo página 66

6 Checking the volume
1. Setting the nominal volume
a.
Set the maximum specified instrument volume (for procedure, see Pipetting, p. 55).
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*:
100 s
CV% =
V
*) = Calculation for accuracy (A%) coefficient of variation (CV%): A% and CV% are calculated using the
formulas of statistical quality control.
66
Operating manual
NOTICE
NOTICE
n = number of weighings
Mean volume:
Standard deviation*:
V = nominal volume
0
Accuracy*:
– V
V
0
A% =
* 100
V
0
Transferpette® -8/-12 electronic 997200