10
as standard deviation s = ∑(V
i
- ⊽)
2
n - 1
n = number of measurement (10)
or as coefficient of variation CV = 100s/⊽
14. Compare the systematic error (inaccuracy)
and random error (imprecision) with the
values in the performance specifications
- (p. 88) or the specifications of your own
laboratory.
If the results fall within the specifications,
the pipette is ready for use. Otherwise check
both systematic and random errors and,
when necessary, proceed to the recalibration
procedure (Chapter 9.2).
NOTE: Systemic 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: Sartorius 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 pipette (ISO8655-1).
Table 1
Z-values (µl/mg):
Temp. (°C) Air Pressure (kPa)
95 100 101.3 105
20.0
20.5
21.0
21.5
22.0
22.5
23.0
23.5
1.0028
1.0029
1.0030
1.0031
1.0032
1.0033
1.0034
1.0036
1.0028
1.0029
1.0031
1.0032
1.0033
1.0034
1.0035
1.0036
1.0029
1.0030
1.0031
1.0032
1.0033
1.0034
1.0035
1.0036
1.0029
1.0030
1.0031
1.0032
1.0033
1.0034
1.0036
1.0037
NOTE: This method is based on ISO 8655.
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