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.
Source:
PAC, 1985, 57, 1491
(Recommended terms, symbols, and definitions for electroanalytical chemistry (Recommendations 1985))
on page 1500