ABSTRACT
Electroanalytical chemistry is the use of electrochemical techniques to characterize a sample. Gas-sensing electrodes are really entire electrochemical cells that respond to dissolved gas analytes or to analytes whose conjugate acid or base is a gaseous species. The sign of half-cell potentials has been defined in a number of different ways, and this variety of definitions has led to considerable confusion. The characteristics of an ideal reference electrode are that it should have a fixed potential over time and temperature, long-term stability, and the ability to return to the initial potential after exposure to small currents, and it should follow the Nernst equation. Based on the potential developed in a half-cell under controlled conditions, the elements may be arranged in an order known as the activity series or electromotive series. Two common reference electrodes that come close to behaving ideally are the saturated calomel electrode and the silver/silver chloride electrode.
