Thermo Fisher Scientific Ion Selective Electrodes Chloride - Manual (Page 14)

Instruction Manual Chloride Electrode
The time needed to reach 99% of the stable electrode potential reading, the electrode response time,
varies from several seconds in highly concentrated solutions to several minutes near the detection
limit. (Refer to Figure 2.)
A drifting potential reading or a decrease in electrode slope may mean that the electrode membrane
needs polishing.
To polish the membrane:
1. If using polishing paper, cut off a 1-2" piece and place it face up on the lab bench.
2.
Put a few drops of distilled or deionized water in the center of the paper.
3.
Holding the paper (cotton) steady with one hand, bring the membrane of the electrode
down perpendicular to the paper and, with a slight swirling motion, gently polish the tip of
the electrode against the surface of the polishing paper (cotton) for a few seconds.
4. Rinse the electrode surface with distilled or deionized water and soak the electrode tip in
standard solution for about five minutes before use.
5.
If using jeweller's rouge, place a cotton ball on the table top and flatten it using the bottom
of a beaker.
6.
Put 1-2 drops of distilled or deionized water in the center of the cotton pad. Add a small
amount of jeweller's rouge to the damp cotton.
7.
Continue with Steps 3 and 4 above.
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