Reduction potential (also known as
redox potential,
oxidation / reduction potential,
ORP,
pE,
e, or
) is a measure of the tendency of a
chemical species to acquire
electrons and thereby be
reduced. Reduction potential is measured in
volts (V), or millivolts (mV). Each species has its own intrinsic reduction potential; the more positive the potential, the greater the species' affinity for electrons and tendency to be reduced. ORP is a common measurement for water quality.