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Reference Electrode is a widely used in the cathodic protection
Sep 11, 2017

       silver reference electrode and copper reference electrode are the two most common Reference Electrode,As everyone knows;The problem of the reference electrode is mostly blocked at the liquid junction,when it happens,how to deal with and which method for checking reference electrode we can choose?


       Method for checking reference electrode

       Reference electrode inspection method is divided into internal resistance check method, electrode potential inspection method and appearance inspection method

        1、Internal resistance check method: the internal resistance of the reference electrode is generally less than 10KΩ, the test can be used when the laboratory conductivity meter, conductivity meter socket one end of the reference electrode, the other end of a wire, the reference electrode and metal Silk at the same time immersed in the solution, the internal resistance should be less than 10KΩ. If the internal resistance of the liquid interface part of the blockage, the electrode needs to be processed.

        2、Electrode potential test: using a good reference electrode, the pH electrode input is connected to the reference electrode with poor performance, and the two electrodes are immersed in the KCL solution (or pH=4) at the same time. 00 buffer) if the two electrodes are the same type, the potential difference should be less than 3MV or the potential change is less than 1mv. If the potential difference is greater than 3MV or the potential change is greater than 1mV, the electrode should be replaced or regenerated.

        3、Visual inspection: a good calomel electrode, SCE core mercury, mercuric chloride, cotton three layer interface should be clear, bright color is mercury, mercuric chloride was gray. Ag-AgCL electrode is dark brown, if gray, it explains AgCL part decomposition.


       Method for regenerating reference electrode

       The problem of the reference electrode is mostly blocked at the liquid junction,the following methods can be used to eliminate the general:

       1、Immersion liquid junction: crystallization from solution to electrode but endpoint. Configure 10% saturated KCL solution and 90% deionized water mixture. Heat the mixture to (60-70) 0C and immerse the electrode in the heat mixture for about 20 minutes to 2 hours. The solution is submerged and the electrode tip is crystallized.

       2、Ammonia immersion Ag-AgCL electrode liquid junction were often AgCL blocked, remove the best method of AgCL by ammonia. The specific operations are as follows: drain the Ag-AgCL electrode, fill the liquid, immerse the electrode in the concentrated ammonia water (10-20) minutes, remove the electrode and rinse with deionized water (Note: do not let the strong ammonia water into the electrode inside).

      3、Vacuum treatment: the easiest method is to use a suction pump, hose on the reference electrode of liquid junction, open flow caused by vacuum suction liquid flowing through the liquid junction, remove mechanical blockage.

      4、Boil the liquid junction: (this method cannot be used only for calomel electrode, Ag-AgCL electrode). Partially immersed in boiling water should not exceed the liquid junction electrode (10-20) in the next seconds, before the boiling, the electrode should be cooled to room temperature.

      5、When the method fails, available this grinding liquid junction part, eliminate blockage by mechanical method. The biggest drawback of this method is when grinding sand grinding and plug the liquid junction and permanently blocked the consequences. This method may be used if the electrode is not suitable for use.

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