RADIOMETER ABL800 FLEX - Page 49

2. Amperometric measuring principles ABL800 FLEX Reference Manual
pO
2
electrode, Continued
The pO
2
measured from the sample is then corrected for systematic deviations
from the reference method using the following equation:
Corrections -
expired air
samples
)OH(A(sample)OAcorr)(sample,O
21202
pBpp
−
×
+
×
=
where:
pO
2
(sample) = uncorrected pO
2
value of a expired air sample
pO
2
(sample,corr) = corrected pO
2
value of a expired air sample
A
0
= instrument dependent correction factor
A
1
= instrument-dependent correction factor
B
= barometric pressure during the measurement
pH
2
O
= partial pressure of saturated water vapour = 6.2571 kPa
ABL800FLEX Mode A
0
A
1
Equation
All Expired air 1.016 -0.004 A
When measuring on gas samples, the constant K
1
(describes the gas/liquid
relationship for the electrode) is equal to 1.
Stability criteria
The following stability criterion must be met to obtain a stable electrode response
during
calibration:
)i.upd(sample,Oupd.last)(sample,O
22
pp − ≤ pO
2
(limit)
This criterion is valid for 1-point calibrations (Gas 2 contains no oxygen) where:
Parameter pO
2
value from the last updating number...
ABL8X5 FLEX ABL8X0 FLEX
pO
2
(Gas1,upd.last) 92 62
pO
2
(Gas1,upd.i) 86 or 87 56 or 57
(the relationship must be fulfilled for at least one of
the updating numbers)
pO
2
(limit) value for the stability criterion is 0.80 kPa/6.0 mmHg.
Continued on next page
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