In voltammetry and related techniques, a substance that undergoes a change of oxidation state, or the breaking or formation of chemical bonds, in a charge-transfer step. If an electroactive substance B
is formed, in the solution or electrode, by a chemical reaction from another substance C
, the substance C
should be called the precursor of B
. In potentiometry with ion-selective electrodes, a material containing, or in ion-exchange equilibrium with, the sensed ion. The electroactive substance is often incorporated in an inert matrix such as poly(vinyl chloride) or silicone rubber.
PAC, 1985, 57, 1491. 'Recommended terms, symbols, and definitions for electroanalytical chemistry (Recommendations 1985)' on page 1500 (https://doi.org/10.1351/pac198557101491)