13. For conformity evaluation calculate the random error of the
measurement:
as standard deviation s =
∑
(V
i
– V)
2
n = number of
measurement (10)
n – 1
or as coefficient of variation CV = 100
s
/V
14. Compare the systematic error (inaccuracy) and random error
(imprecision) with the values in the performance specifications
(page 81) or the specifications of your own laboratory.
If the results fall within the specifications, the pipettor is ready for
use. Otherwise check both systematic and random errors and,
when necessary, proceed to the recalibration procedure
(Chapter 11.2).
Note
: Systematic error (inaccuracy) is the difference between the
dispensed volume and the selected test volume. Random error
(imprecision) is the scatter of the dispensed volumes around the mean
of the dispensed volume. (ISO 8655-1.)
Note
: Biohit specifications are achieved in strictly controlled conditions
(ISO 8655-6). The user should establish own specifications based on
the field of use and the accuracy requirements placed on the pipettor
(ISO8655-1).
Table 1
Note: This method is based on ISO 8655.
Z-values (
µ
l/mg):
Temp. (°C)
Air Pressure (kPa)
95
100
101.3
105
20.0
1.0028
1.0028
1.0029
1.0029
20.5
1.0029
1.0029
1.0030
1.0030
21.0
1.0030
1.0031
1.0031
1.0031
21.5
1.0031
1.0032
1.0032
1.0032
22.0
1.0032
1.0033
1.0033
1.0033
22.5
1.0033
1.0034
1.0034
1.0034
23.0
1.0034
1.0035
1.0035
1.0036
23.5
1.0036
1.0036
1.0036
1.0037
13
