Ag/AgCl reference electrode

Instructions for using Ag/AgCl reference electrode
The Ag/AgCl reference electrode is composed of a silver wire coated with silver chloride (with a white polytetrafluoroethylene cap), a glass tube (i.e. the reference electrode chamber), and a "microporous ceramic head" sealed in the glass tube.
The reference electrode chamber is filled with saturated KCl solution. You can fill it with other concentrations of KCl. The relative voltage between the reference electrode and the standard hydrogen electrode can be calculated by the activity of Cl - ions:
EAg/AgCl= 0.222-0.059logACl-Volt@25oC
Before using the reference electrode, please remove the black electrode cap and observe whether there are bubbles at the bottom of the glass tube. If there are bubbles, you can use your fingernail to tap the bubble and push the air towards the upper part of the electrode chamber. It is normal to have a small amount of salt crystals around the outer wall of the glass tube, which is a slowly leaking KCl solution in the glass.
When using, if you feel an increase in resistance, it may be because the "microporous ceramic head" has dried up. At this time, you can pull out the white polytetrafluoroethylene cap of about 6mm from the glass tube, let a little air enter the glass tube, then place the glass tube vertically and use your fingernail to bounce the bubbles and drive them to the upper part of the electrode chamber. Then insert the glass tube back into the electrode cap. This is the KCl solution that should be able to be squeezed out from the "microporous ceramic head". After the above operation, the resistance should decrease and the electrode can be used normally.
The solution in the glass tube can be replenished. Please check the solution height. If the solution height is too low, you can use KCl solution again (default is saturated). When injecting the solution, please carefully remove the white PTFE cap, fill the glass tube with the solution using a syringe, confirm that there are no bubbles at the bottom of the glass tube, then inject a small amount of solution into the white PTFE cap, and insert the glass tube into the white PTFE cap.
When taking the black electrode cap, do not expose the "microporous ceramic head" to air for a long time (more than a few minutes), otherwise the solution in the glass tube will leak and evaporate, and the "microporous ceramic head" will also dry up. When the electrode is not in use, please immerse it in 3M KCl solution (or other concentrations of KCl solution) to ensure the conductivity of the "microporous ceramic head".