Xylem wtw CN 800 DIN, Operating Manual

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ba15356d04 12/2021
Response times CN 800
Response times
The response time depends on the concentration range. It is

several seconds at high concentrations,

several minutes near the detection limit.
The measured value is stable if the value does not change by more than
0.1 mV within 30 seconds.
Interferences

Complexes with Ni
2+
, Cd
2+
, Cu
2+

Strong reducing agents

Interfering ions: 10 % error with the following concentration ratio
(concentration ratio = interfering ion / measured ion):
Aging
Please note that every electrode undergoes a natural aging process. The re-
sponse time increases and the slope decreases with the age of the electrode.
The following factors shorten the lifetime considerably:

Unsuitable storing conditions (see section S
TORAGE
)

Special measuring conditions (e.g. organic solutions, frequent measure-
ment with high concentrations of interfering ions)

High temperatures

High changes in temperature
The warranty does not cover damage caused by measuring conditions and
mechanical damage.
Maintenance

Combination electrodes:
Refill any used up bridge electrolyte.

In the case of increased response times of the electrode perform the fol-
lowing activities:
– Polish the membrane surface using an SF/K polishing strip (see section
R
ECOMMENDED ACCESSORIES
). To do so, moisten a polishing strip with
deionized water, and with circular movements polish the membrane
surface for approx. 30 seconds.
– Then recondition the electrode (see section C
ONDITIONING
,
Cl
-
I
-
Br
-
S
2-
1x10
6
0.1 5x10
3
must not be present