LESSON 3
electrode) and a reference electrode in one assembly. This electrode also
has a plastic coating to protect the sensitive glass tip.
d. The chemical mixture in the reservoir is a potassium chloride
solution saturated with silver chloride.
The level of solution should be
kept directly beneath the filling hole which should be uncovered when not
being used.
e. The electrode should be stored in tap water or pH 4.01 buffer. Do
not store it in basic (alkaline) solutions, because they tend to etch the
glass.
f. For other types of electromechanical potential measurement, such as
oxidation reduction, a metallic electrode is substituted for the glass
electrode and the readout is in millivolts. Do not use metal electrodes for
testing developers.
g. The actual use of a pH meter is up to the brand name available to
you. There will be detailed instructions for each type of meter, and how to
use it (furnished with the equipment).
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