Legend

1. a sensing part of electrode, a bulb made from a specific glass
2. internal electrode, usually silver chloride electrode or Saturated calomel
3. internal solution, usually 1.10^-7 mol/L HCl for pH electrodes or 0.1 mol/L MeCl for pMe electrodes
4. when using the silver chloride electrode, a small amount of AgCl can precipitate inside the glass electrode
5. reference electrode, usually the same type as 2
6. reference internal solution, usually 0.1 mol/L KCl
7. junction with studied solution, usually made from ceramics or capillary with asbestos or quartz fiber.
8. body of electrode, made from non-conductive glass or plastics.