Determination of dissolved oxygen with a Clark cell
Constitution of the cell
A Clark cell consists of a platinum (Pt) electrode and a circular silver (Ag) electrode in contact with an electrolyte solution (KCl at 175 g/L or Na3PO4 at 50 g/L). This assembly is isolated from the external environment (solution or gas to be analyzed) by means of polytetrafluoroethylene membrane (PTFE or Teflon).
The platinum electrode can be either disc-shaped or cylindrical. The silver electrode does not necessarily coat the side of the electrode. A golden plate, connected to a golden wire, may also replace the platinum electrode.