Adjustment - BRAND Dispensette S Instrucciones De Manejo

9 Adjustment

3. Calculation
= Weighing results
x
i
Correction factor
Z =
(e.g. 1.0029 µl/mg at 20 °C, 1013 hPa)
Mean
Mean volume
Accuracy*
Coefficient of variation*
Standard deviation*
9 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), p. 53).
b.
Calculate mean volume (actual value) (Checking the Volume (Calibration), p. 53).
c.
Adjust the instrument (to the calculated mean volume).
d.
After the adjustment, further calibration is necessary to confirm the appropriate adjustment.
Example
The gravimetric check gives an actual value of 9.90 ml for a 10 ml instrument set for a nominal volume
of 10.00 ml.
54
Operating manual
Number of weighings
n
=
∑
x
x –
i
=
n
—
.
x –
Z
V
=
—
V
V
–
0
A% =
V
0
V
Nominal volume
0 =
100 s
CV%
=
—
V
.
Z
s
=
.
100
x –
∑
2
)
(
–
x
i
n – 1
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