https://doi.org/10.1351/goldbook.09106
Electrode coated with a thin layer of a substance that exhibits particular chemical, electrochemical, and/or optical properties.
Notes:
- The layer may be monomolecular, multimolecular, ionic, or polymeric in structure.
- The substance is termed a chemical modifier.
- For electroanalytical purposes, a CME is designed for use as a predominantly voltammetric or amperometric device, but examples of potentiometric, impedimetric, or microgravimetric sensing devices are known.
- A CME is prepared by the deliberate modification of the surface or bulk matrix material of the electrode with a selected reagent (monomeric or polymeric) that governs its electrochemical properties. Such manipulation of the molecular composition of the electrode aims to improve sensitivity, selectivity, and/or stability, allowing for the tailoring of its response to meet analytical needs.
- The range of electrode surface properties sought is broader than that of ion-selective electrodes (ISEs), which also involve the rational design of the phase-boundary, partition, and transport properties of membranes on or between electrodes. CMEs also differ from ISEs in that they are generally used voltammetrically or amperometrically, a faradaic (charge transfer) reaction being the basis of measurement, whereas ISEs are generally used in potentiometric mode, the measured quantity being a phase/boundary potential (interfacial potential difference).