Amersham Pharmacia Biotech AKTA design pH/C-900, Руководство пользователя

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Monitor pH/C-900
User Manual 18-1120-06 Edition AC 10
3
Operation
8 The sub menu
Calibrated
Electrode Slope
shows the
slope of the calibration curve
where 100% corresponds to
59.16 mV per pH step at
25°C. The asymmetry
potential at pH 7 is shown
as a mV value. Press ESC to
return to the main menu.
9 Before use, rinse the
electrode using distilled
water.
A new electrode has a slope of, typically, 95 - 102% and an
asymmetry potential within ±30 mV. As the electrode ages the slope
decreases and the asymmetry potential increases.
As a rule, when an electrode has an asymmetry potential outside of
±60 mV and a slope lower than 80%, and no improvement can be
achieved by cleaning, it should be replaced.
An electrode is still usable at lower slopes and higher asymmetry
potentials but the response will be slower and the accuracy
diminished.
Calibrating with the electrode in the flow cell
When calibrating with the electrode fitted in the flow cell in
ÄKTApurifier, follow the above procedure. Before adjusting the pH
monitor, ensure that the pH has stabilized. Leave the pump running
while calibrating. Switch to the other standard buffer solution and
repeat the procedure. For a description of calibration from
UNICORN with the electrode fitted in the flow cell, see section 6.6
in UNICORN User Manual.
Voltage (mV)
pH
0 mV
+500 mV
–500 mV
7
Asymmetry
potential
at pH 7
Calibration curve
The calibration curve
shows the relationship
between pH and the
output signal from the
monitor in mV.
Calibrated Electrode
Slope 97.5% 8 mV
18-1120-06_AC.qxd 1999-04-14 14:16 Sida 10 (1,1)