Checking The Volume (Calibration) - BRAND seripettor Operating Manual

7 Checking the Volume (Calibration)

Depending on use, we recommend that gravimetric testing of the instrument be carried out every 3-12
months. This time frame should be adjusted to correspond with individual requirements. The com-
plete testing procedure (SOP) can be downloaded at www.brand.de. For GLP- and ISO-compliant eval-
uations and documentation, we recommend the EASYCAL™ calibration software from BRAND. Demo
version can be downloaded from www.brand.de. Gravimetric volume testing according to DIN EN ISO
8655- 6 (for measurement conditions, see Error limits, p. 66) is performed as follows:
1. Prepare the instrument
Clean the instrument (Cleaning, p. 68), fill it with distilled H
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 from
997468
O and weighings in 3 volume ranges (100 %, 50 %, 10 %)
2
n = number of weighings
Mean volume:
Standard deviation*:
NOTICE
www.brand.de
7 Checking the Volume (Calibration)
O and then prime it carefully.
2
V = nominal volume
0
Accuracy*:
V
A% =
.
– V
0
* 100
V
0
Operating manual
67