Checking The Volume (Calibration) - BRAND Dispensette S Operating Manual

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 complete
testing procedure (SOP) can be downloaded at www.brand.de. In addition, you can also perform a func-
tion test at shorter intervals, e.g. dispensing the nominal volume into a volumetric test flask (volumetric
flask with 3 marks, DAkkS calibrated). For GLP- and ISO-compliant evaluations and documentation, we
recommend the EASYCAL
www.brand.de.
Gravimetric volume testing according to DIN EN ISO 8655-6 (for measurement conditions, see 'Error
Limits', page 46) is performed as follows:
1.
Preparation of the instrument
Clean the instrument ('Cleaning', page 49-52), fill it with distilled H
and then prime it carefully.
2.
Check the volume
a) 10 dispensing operations with distilled H
3 Volume ranges (100 %, 50 %, 10 %) are recommended.
b) For filling pull up the piston gently until the upper stop of the volume
set.
c) For discharge depress piston slowly and steadily without force until
the lower stop.
d) Wipe off the tip of discharge tube.
e) Weigh the dispensed quantity on an analytical balance. (Please follow
the operating manual of the balance manufacturer.)
f) Calculate the dispensed volume. The Z factor takes account of the
temperature and air buoyancy.
3.
Calculations
Mean volume
x = results of weighings
i
n = number of weighings
Σ x
Mean value x =
n
Accuracy
V – V
0
A% = · 100
V
0
V = nominal volume
0

Checking the Volume (Calibration)

™ calibration software from BRAND. A demo version can be downloaded from
Z = correction factor
(e. g., 1.0029 µl/mg at 20 °C, 1013 hPa)
i Mean volume V = x · Z
Standard deviation
s = Z ·
O in
2
Σ (x
– x )
2
i
n – 1
O
2
Coefficient of variation
100 s
CV% =
V
47