NH 500/2
Measuring / operation
13
Getting the sensor
ready for
measuring
On delivery, the electrode is equipped with the storing cap (without the white,
gas-permeable membrane).
l
Remove the storing cap.
l
Rinse the electrode with deionized water.
l
Fill approx. 1 ml NH
3
electrolyte solution into a membrane cap.
l
Remove air bubbles in the electrolyte by knocking.
l
Screw the membrane cap on the electrode.
l
Connect the electrode to the meter using the connection cable.
l
Keep the storing cap. It serves as a protective cap if the
electrode is stored for a longer period of time.
4
Measuring / operation
4.1
Calibration
Note
For calibration, please refer to the operating manual of the measuring
instrument.
Typical calibration
line of an ammonia
electrode
4.2
Sample preparation
Add 1 % alkaline reagent (MZ/NH
3
/CN) to the aqueous sample. It is essential
to observe the WTW application reports and analysis specifications
respectively.
0.1
80
40
0
-40
-80
-120
-160
-200
1
10
10
-6
10
-5
10
-3
10
-2
10
-1
10
-4
100
1000
~ 55 ... 59 mV
mV
mg/l NH
4
mol/l NH
4
Electrode voltage
tenfold
concentration change
+
+