YSI IQ S ENSOR N ET TriOxmatic 700 IQ (SW) - Manual (Page 42)

Maintenance, cleaning, disposal, and replacement TriOxmatic
®
700 IQ (SW)
5 - 20 ba76013e01 01/2012
5.5 Checking the sensor for freedom from zero-current
The sensor is zero-current free. Therefore, calibration of the sensor in
oxygen-free solution is not provided.
However, it is possible to check the freedom from zero-current
according to DIN EN 25814/ISO 5814. This is advisable if there is any
suspicion of a malfunction.
Test solution 1 g/l aqueous sodium sulfite solution, Na
2
SO
3
(addition of 1 mg/l of a cobalt(II) salt accelerates the removal of oxygen
from the solution.)
The sensor should be in operation for at least 1 hour before the
inspection.
Test procedure
Test criterion The sensor is OK if < 2 % oxygen saturation is displayed as the
measured value.
If the measured value is > 2 %:
 Clean the gold working electrode (see section 5.4.1 C
LEANING THE
GOLD WORKING ELECTRODE ) and change the electrolyte and
membrane cap (see section 5.3 C HANGING THE ELECTROLYTE AND
MEMBRANE CAP ).
 If necessary, also clean the silver counter electrode (see section
5.4.2 C LEANING THE SILVER COUNTER ELECTRODE ).
1 Clean the sensor (see section 5.2 C LEANING THE SENSOR SHAFT
AND MEMBRANE ).
2 In the sensor setting table, select the measuring mode
Saturation (unit %) and switch to the measured value display
with
m
.
3 Submerse the sensor in the test solution.
4 Leave the sensor in the test solution for an hour.
5 Read the measured value.