1. Preparation of the instrument
Clean the instrument (‚Cleaning‘, page 40-
41), fill it with distilled H
2
O and then prime it
carefully.
2. Check the volume
a)
10 dispensing operations with distilled H
2
O in
3 Volume ranges (100 %, 50 %, 10 %) are
recommended.
b)
For filling pull up the piston gently until the
upper stop of the volume set.
Gravimetric volume testing according to DIN EN ISO 8655-6 (for measurement conditions, see ‚Error Limits‘,
page 37) is performed as follows:
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. In addition, you
can also perform a function test at shorter intervals, e.g. dispensing the nominal volume into a volumetric
test flask.
10. Checking the Volume (Calibration)
Calculations for nominal volume V
N
x
i
= results of weighings
n = number of weighings
Z = correction factor
(e. g., 1.0029 µl/mg at 20 °C, 1013 hPa)
Mean value
x =
Σ
x
i
n
Mean volume
Accuracy
Coefficient of variation
Standard deviation
V = x · Z
100 s
V
CV% =
Σ
(x
i
– x)
2
n – 1
s = Z ·
V – V
N
V
N
A% = · 100
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.
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