BRAND Dispensette S Instrucciones De Manejo página 60

8 Adjustment
2. Check the volume
a.
At 10 pipetting series with destilled H
are recommended
b.
For discharge, depress the piston slowly and steadily without force until the lower stop
c.
Wipe off the tip of titration tube.
d.
Weigh the pipetted amount with an analysis scale. (Please refer to the user manual of the scale
manufacturer.)
e.
Calculate the dispensed volume. The Z factor takes account of the temperature and air buoy-
ancy.
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
*) Accuracy and coefficient of variation are calculated according to the formulas of statistical quality
control.
Test instructions (SOPs) are available for download at www.brand.de .
8 Adjustment
After a long period of usage, an adjustment of the instrument might be necessary.
a.
Calibrate for example at nominal volume (Checking the Volume (Calibration)).
b.
Calculate mean volume (actual value) (Checking the Volume (Calibration)).
c.
Adjust the instrument (to the calculated mean volume).
d.
After the adjustment, further calibration is necessary to confirm the appropriate adjustment.
Example
60
Operating manual
O and weighings in 3 volume ranges (100 %, 50 %, 10 %)
2
n = number of weighings
Mean volume:
Standard deviation*:
NOTICE
V = nominal volume
0
Accuracy*:
– V
V
0
A% =
* 100
V
0
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