7 Reference7.2 mV (oxidation-reduction potential [ORP]) measurement180 HORIBA7.2 mV (oxidation-reduction potential [ORP])measurementORP principlesORP is an abbreviation for oxidation-reduction potential.ORP is the energy level (potential) determinedaccording to the state of equilibrium between theoxidants (Mz+) and reductants (M(z-n)+) that coexistwithin a solution.For one type of equilibrium in a solution:Mz++ne- M(z-n)+ ••••••If only exists within a solution, a metal electrode(platinum, gold, etc.) and a reference electrode areinserted into the solution, forming the ORP measuringsystem shown in Fig. 1. Measuring the potential (ORP)that exists between the two electrodes enables thepotential to generally be expressed by the followingequation.••••••E: Electric potential E0: Coefficient R: Gas coefficientT: Absolute temperature n: Electron countF: Faraday constant a: ActivityFig. 1 ORP measuring system–( )–Potentiometer
