Double Junction Reference Electrode

 

A double junction reference electrode is used to minimize contamination of the solution being measured. Most often, chloride is the contaminant of concern. Reference electrodes are often filled with a saturated solution of very soluble KCl. Even the small amount of flow through the junction can produce a significant chloride concentration in the test solution.

A double junction reference has two junctions. The first separates the reference electrode from an intermediate solution. This solution is then isolated from the test solution by a second junction.

The intermediate solution is generally not as conductive as the KCl in the reference electrode junction, so the impedance of a double junction reference is usually more than twice that of a single junction electrode.

 

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Last revised on Thursday, August 30, 2007