YSI TruLine ORP 50 - Manual (Page 10)

10 T 814241 04/2014
Activating platinum electrodes TruLine
CleaningIL Remove water-soluble contamination by rinsing with deionized water. Re-
move other contamination as follows:
Contamination Cleaning procedure
Fat and oil Rinse with water containing household wash-
ing-up liquid
Lime and hydroxide deposits Rinse with citric acid (10 % by weight)
After cleaning Rinse the combination electrode with deionized water.
First-time
activation during
installation and as
required
Activating platinum electrodes
For the first-time activation use the activation powder from the SORT/RH
reagent set (component of the SORT/RH reagent set). Immerse the moist
(but not dripping) platinum electrode into the activation powder and rotate the
electrode several times in the powder. Then remove the activation powder
under flowing water with a soft brush (e.g. toothbrush).
Activation during
very long
set-up times
When changing from oxidizing to reducing test solutions and vice versa this
can result in set-up times that can take significantly more than an hour. In this
case pretreatment (activation) of the platinum surface can shorten the set-up
time. The type of pretreatment (reducing or oxidizing) is based on the pH val-
ue and the ORP voltage (U
H
) of the test solution where the latter must be es-
timated for the first measurement.
The type of pretreatment can then be determined using the following diagram
where U
H
is based on the normal hydrogen electrode:
1000
U
H
in mV
800
600
400
200
0
oxidizing pretreatment
reducing pretreatment
0 2 4 6 8 10 12 14
pH value