RADIOMETER ABL800 FLEX, Справочное руководство

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ABL800 FLEX Reference Manual 2. Amperometric measuring principles
Metabolite electrodes,
Continued
Sensitivity The sensitivities of the metabolite electrodes are calculated by measuring the
current on Calibration Solution 1 (Cal 1) and then correcting for the zero current
using the extrapolated I
0
baseline.
Cal 1 has a nominal glucose concentration of 10 mmol/L and a nominal lactate
concentration of 4 mmol/L. The precise values are batch-individual and contained
in the bar codes of the Cal 1 bottles.
The diagram below, together with the table, describes in principle how the
sensitivities for the metabolite electrodes are obtained.
I
0
(final)
t
I
x
x x
x x
x
x
x
x
x
x x x
Start of
Calibration
Extrapolated
base-line
N measurements of I
0
on rinse solution
End of
Calibration
I(Cal 1,upd.2)
I(Cal 1)
•
I(Cal 1,upd.1
I(Cal 1,upd.N)
Electrode updatings
The current at the metabolite electrodes with Cal 1 in the measuring chamber,
I(Cal
1), is measured 30 times at regular intervals. The current at the 15
th
updating
is used to determine sensitivity of the glucose electrode, and the current at the 30
th
updating is used to determine sensitivity of the lactate electrode.
The current due to the glucose or lactate presence in the sample is then calculated
as the difference between the current at the final updating (the 15
th
for the glucose
and the30
th
for the lactate electrode) and the zero current at that time point:
I(Cal 1) = I(Cal 1,final)
−
I
0
(final)
The sensitivities of the electrodes are calculated as follows:
1) X(Cal
1) I(Cal
Sens
c
=
T T
Continued on next page
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