Response Times; Interferences; Aging; Maintenance - Xylem wtw CN 800 DIN Operating Manual

Response times

20
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
 Strong reducing agents
 Interfering ions: 10 % error with the following concentration ratio
(concentration ratio = interfering ion / measured ion):
- -
Cl I
6
1x10 0.1

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
 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
deionized water, and with circular movements polish the membrane
surface for approx. 30 seconds.
– Then recondition the electrode (see section C
2+ 2+ 2+
, Cd , Cu
- 2-
Br S
3
5x10 must not be present
). To do so, moisten a polishing strip with
)
TORAGE
,
ONDITIONING
ba15356d04
CN 800
12/2021