YSI 5239 Dissolved Oxygen Probe - Manual (Page 15)

11
E LECTRODE C LEANING
It is always a good practice to keep the probe in good
operating condition.
Silver Anode
After extended use, a thick layer of AgCl builds up on the
silver anode reducing the sensitivity of the sensor. The anode
must be cleaned to remove this layer and restore proper
performance. The cleaning can be chemical or mechanical:
•
Chemical cleaning: Remove the membrane cap and
soak the entire anode section in a 14% ammonium
hydroxide solution for 2 to 3 minutes, followed by a
thorough rinsing with distilled or deionized water.
The anode should then be thoroughly wiped with a
wet paper towel to remove the residual layer from the
anode.
•
Mechanical cleaning: Sand off the dark layer from
the silver anode with 400 grit wet/dry sandpaper.
Wrap the wet sandpaper around the anode and twist
the probe. Rinse the anode with clean water after
sanding, followed by wiping thoroughly with a wet
paper towel.
Gold Cathode
For correct probe operation, the gold cathode must be textured
properly. It can become tarnished or plated with silver after
extended use. The gold cathode can be cleaned by using the
adhesive backed sanding disc and tool provided in the YSI
5238 probe reconditioning Kit.