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Reference
Electrodes
Gamry supplies a Saturated Calomel Reference
Electrode (Part No. 930-03) and a Silver-Silver Chloride Reference
Electrode (Part No. 930-15). Both Reference Electrodes maintain
electrical contact with the supporting electrolyte through replaceable
Vycor Tips (Part No. 955-03 (package of 5)). The Vycor Tip provides a
nice, low-impedance contact so you won't encounter any noise
pick-up.
Show me a photo of the SCE Reference.
Show me a photo of the Silver-Silver
Chloride Reference.
It is very, very important that your Reference Electrode behave itself at
all times. Of the Working, Reference, and Counter, it is the
Reference Electrode that is most likely to malfunction and cause
substantial pain and misery. For some comments from the Department of
Been-There-Done-That, see our Application Note on Reference
Electrode Effects on Potentiostat Performance. We
also advise you to "manage" the Reference Electrodes with a Lab
Master.
Sometimes a classical reference electrode like an SCE isn't
practical. For example, if you're doing three-electrode
electrochemistry in the field, then a glass electrode is liable to break.
For field work, many people use a metal probe made from the same material
as the Working Electrode. Alternatively, you can use a
corrosion-resistant alloy such as Hastelloy for your reference.
Reference electrodes of this sort are termed "psuedo reference
electrodes".
The other application in which the reference electrode can be a major
headache is high-temperature, high-pressure experiments in an autoclave.
There are many reference electrode designs for autoclaves. One of
the latest is "Simple and Robust External Reference Electrodes for
High-Temperature Electrochemical Experiments" from Bosch, Bogaerts,
and Zheng in CORROSION, Volume 59, page 163 (2003). That's the February
2003 edition.
Since an autoclave is ALWAYS grounded, you must use a potentiostat that is
electrically floating. A good choice would be...GAMRY!!! All
Gamry Potentiostats float, that is, they are electrically isolated from
ground, so they work very well in a grounded cell such as an
autoclave. Because of this feature, Gamry Potentiostats are used in
a wide number of laboratories for high-temperature experiments. If
you are pursuing this type of experiment, we'd be happy to save you some
time by putting you in touch with a Gamry user who is using our
Potentiostats in an autoclave for their comments and suggestions.
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