Dear Sa’Adatu Ocheni

It is very simple to make Cu-ref electrode. You need a plastic or glass tube. On one side glue by the epoxy ceramic frit, after drying fill the tube with saturated CuSO4 (containing solid phase,). On the upper part of the tube insert, for example, rubber stopper, through which thick spiral Cu wire (previously cleaned in nitric acid, washed and dried) is inserted. After 24 h the potentials should be 0.31-0.32 V vs SHE or 0.065-0.075 V vs. SCE. The temperature variation is approximately +0.9mV/°C thus a pipe/soil potential measured with a reference electrode at 25°C as ‘protected’ to -0.850V will display -0.832V if the electrode temperature is 5°C.

As Branimir N. Grgur .

Also, there are some references[1-6] explaining[2,3] the process.

1. Reference cell without chlorides are recommended.

2. HOW TO PREPARE AND MAINTAIN PORTABLE M.C.MILLER COPPER SULFATE REFERENCE ELECTRODES https://d163axztg8am2h.cloudfront.net/static/doc/99/f5/a41210f6659ef9badd1787236f32.pdf

3. Copper sulfate reference electrode https://www.sciencedirect.com/science/article/pii/S1572665711002591 https://www.researchgate.net/publication/251697438_Copper_sulfate_reference_electrode

4. Portable Copper-Copper / Sulfate Reference Electrodes https://www.farwestcorrosion.com/portable-copper-copper-sulfate-reference-electrodes.html

5. Copper/Copper Sulfate Reference Electrode https://www.corrosion-doctors.org/Corrosion-Thermodynamics/Reference-Half-Cells-Copper.htm

6. Reference Electrodes https://www.bornagodaz.com/en/products1/reference-electrodes-and-accessories/reference-electrodes