A.1.2 Cleaning; A.1.3 Chloridisation - ABB Sonde Ammoniac 8002 Manuel D'instructions

...APPENDIX

A.1.2 Cleaning

Immerse the lower 5cm of the combination
electrode (i.e. so that the silver reference
element is covered) in the ammonia solution for
about one minute. Remove and rinse with
distilled water.
Immerse the electrode to the same depth in the
25% nitric acid until the silver element is a
uniform creamy white. This process usually
takes about one minute but the element must be
inspected frequently as prolonged immersion
is detrimental.
If the element is not uniform in colour repeat the
ammonia/nitric acid process.
When clean, rinse with distilled water and
immediately transfer to the plating solution such
that the reference element is completely
immersed.
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A.1.3 Chloridisation

Attach the screen of the combination electrode
cable to the negative terminal of the constant
current supply and immerse the lower 5cm of
the electrode in the plating solution so that the
reference element is covered. Immerse a silver
counter electrode in the plating solution and
connect to the positive terminal of the supply.
Pass a current of 2mA for approximately 30
seconds. Carefully tap the electrode to remove
all bubbles and then reverse the connections to
the supply (i.e. the electrode to be plated is
connected to the positive terminal).
Pass a current of 2mA for 30 minutes after which
time the electrode will be a dark brown or grey
colour. A more uniform coating may be obtained
by employing moderate stirring during the
process
Remove the electrode from the plating solution,
rinse with /distilled water and dry with a tissue.