Expert Tip #20: Copper-Copper Sulfate Reference Electrode Maintenance
Portable copper-copper reference electrodes require maintenance to maintain the integrity of readings taken when using the electrode.
Frequency
Maintenance should be done on a periodic basis depending on how often the electrode is used or the conditions in which it is used. A good rule of thumb for rejuvenating an electrode is when the copper sulfate liquid inside the electrode becomes “milky” as the color should be a very bright blue.
Maintaining or Rejuvenating Portable Copper-Copper Reference Electrodes
- Open the reference electrode by unscrewing the plastic end cap where the copper rod is mounted.
- Properly dispose of the liquid copper sulfate.
Note: This liquid is hazardous. Proper safety measures should be employed including the use of safety glasses and disposable gloves.
- Clean the internal copper rod with a non-metallic abrasive, such as sandpaper or a scouring pad. This will remove any patina or impurities from the rod.
Note: NEVER use metallic abrasives to clean the rod, such as an emery cloth, as it will contaminate the copper rod.
- Add new, pure copper sulfate crystals to the interior of the reference electrode by removing the end cap of the electrode. Fill the electrode cavity to approximately one-third to half full.
- Add clean, distilled water to the interior of the electrode filling the electrode to almost full.
Note: NEVER use tap water for this purpose.
- Replace the plastic end cap by threading it back onto the electrode body.
- Ensure the ceramic tip of the electrode is clean and in good condition. A cracked ceramic tip should be replaced with a new tip to avoid excessive electrolyte leakage.