YSI IQ S ENSOR N ET TriOxmatic 702 IQ - Manual (Page 37)

TriOxmatic
®
702 IQ Maintenance, cleaning, disposal, and replacement
5 - 15 ba76048e01 01/2012
5.5 Check the sensor for freedom from zero current
The sensor is zero-current free. Therefore, no calibration of the sensor
in an oxygen-free solution is included.
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
Evaluation The sensor is OK if the terminal shows < 1 % oxygen saturation.
If the measured value is > 1 %:
 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 %
(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.