Copper–copper(II) sulfate electrode

The copper–copper(II) sulfate electrode is a reference electrode of the first kind,[1] based on the redox reaction with participation of the metal (copper) and its salt, copper(II) sulfate.

[2] The corresponding equation can be presented as follow: This reaction characterized by reversible and fast electrode kinetics,[3] meaning that a sufficiently high current can be passed through the electrode with the 100% efficiency of the redox reaction (dissolution of the metal or cathodic deposition of the copper-ions).

The Nernst equation below shows the dependence of the potential of the copper-copper(II) sulfate electrode on the activity or concentration copper-ions: Commercial reference electrodes consist of a plastic tube holding the copper rod and saturated solution of copper sulfate.

A porous plug on one end allows contact with the copper sulfate electrolyte.

A voltmeter negative lead is connected to the copper rod.