A reference electrode is combined with an ion-selective electrode to give a potential difference that depends on the ion concentration. Its reference potential has to be stable. In general, a silver-silver chloride electrode is used as the internal electrode.
The liquid junction area of reference electrodes should always be kept clean since they readily tend to become dirty, resulting in fluctuation of the liquid junction potential. It is important to use a reference electrode for which the fluctuation in liquid junction potential is kept as small as possible.

Precautions for use

  • Do not forget to replenish the internal solution; check that the internal solution and liquid junction area are clean.
  • If the liquid junction area is dirty, take the liquid out and clean the area with water or hot water.
  • If the internal solution is dirty, replace it.