Gilson pipetman - Appendices

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1. Determinethemeanvalueeoftheevapora-
tion loss e
i
that occurs during your pipetting
cycles.ProceedasdescribedinAppendix3
to determine e
i
2. Change the pipette tip and perform
the first weighing. Then, keep a regular
cycle and perform the 10 following
measurements.
3.Calculatethemeanweight
4.Calculatethemeanvolume
Foratemperatureof21.5°Candanairpressure
of1013hPa,theZfactorisequalto1.0032µL/
mg(seetableinAppendix2).
5.Evaluateaccuracy
6.Evaluateprecision(repeatability)
Standard Deviation (SD
W
)
wr = 0.957 mg
w1 = 0.968 mg
w6 = 0.966 mg
w7 = 0.955 mgw2 = 0.960 mg
w8 = 0.972 mgw3 = 0.984 mg
w4 = 0.942 mg
w5 = 0.969 mg
w9 = 0.958 mg
wr rinsing measurement which is
disregarded for the calculation
w10 = 0.967 mg
W =
_
W = (0.968+0.960+0.984+0.942
+ 0.969+0.966+0.955+0.972
+ 0.958+0.967) / 10
_
W =
0.964 mg
_
n number of weighings
W
i
weighing results
Wi
1
n
n
i=1
V = ( W+e ) x Z
V = (0.964+0.018) x 1.0032
_
V =
0.985 µL
_
E = V - V0
V0 true value set on the instrument
E = 0.985 - 1 = - 0.015 µL
E% = (V - V0) x 100 / V0
E% = (-0.015 x 100) / 1 = - 1.50 %
Systematic
error (E):
Relative
error
(E%):
(
W
i - W
)
n - 1
SDw =
2
n
i=1
n
i=1
SD
w
2
= ( Wi - W )
2
1
n - 1
1
9
SD
w
2
=
SD
w
= 0.011 mg
(0.968-0.964)
2
+ (0.960-0.964)
2
+ (0.984-0.964)
2
+
(0.942-0.964)
2
+ (0.969-0.964)
2
+ (0.966-0.964)
2
+
(0.955-0.964)
2
+ (0.972-0.964)
2
+ (0.958-0.964)
2
+
(0.967-0.964)
2
SD
v
= SD
w
x Z
SD
v
= 0.011 x 1.0032 = 0.011 µL
Random error (SDv) :
APPENDIX 1  EXAMPLE OF A PERFORMANCE CHECK
BelowisanexampleofhowtoevaluatetheperformanceofPIPETMAN P10M at 1 µL.