Checking The Volume (Calibration) - VITLAB genius2 Instrucciones De Manejo

10. 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 complete
testing procedure (SOP) can be downloaded at www.vitlab.com. In addition, you can also perform a func-
tion test at shorter intervals, e.g. dispensing the nominal volume into a volumetric test flask.
Gravimetric volume testing according to DIN EN ISO 8655-6 (for measurement conditions, see ‚Error Limits',
page 40) is performed as follows:
1. Preparation of the instrument
Clean the instrument (‚Cleaning', page 43-
44), fill it with distilled H
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.
Calculations for nominal volume V
x = results of weighings
i
n = number of weighings
Z = correction factor
(e. g., 1.0029 µl/mg at 20 °C, 1013 hPa)
Mean value
x =
Mean volume
V = x · Z
Standard deviation
s = Z ·
O and then prime it
2
O in
2
N
Σ x
i
n
Σ (x
– x )
2
i
n – 1
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.
Accuracy
V – V
A% =
Coefficient of variation
CV% =
N · 100
V
N
100 s
V
41