A carbon paste electrode (CPE) is a type of electrode commonly used in electrochemical measurements, particularly in voltammetry. It consists of a mixture of graphite powder (or other forms of carbon) and a liquid or solid binder, such as paraffin oil or silicone oil. This mixture is packed into a non-conductive tube or holder to form the electrode.

Carbon paste electrodes offer several advantages:

Versatility: They can be easily modified by adding various substances to the carbon paste, allowing for selective detection of specific analytes.
Low cost: They are relatively inexpensive to produce compared to some other types of electrodes.
Ease of fabrication: They can be easily fabricated in the lab, and the composition of the paste can be adjusted to suit specific experimental needs.
Reusability: In some cases, carbon paste electrodes can be reused multiple times by simply replenishing the carbon paste.

In voltammetry, which is a technique used to study the relationship between current and applied potential in an electrochemical cell, carbon paste electrodes are often employed as working electrodes. They are particularly useful for studying redox reactions and measuring concentrations of various substances in solution, including metals, organic compounds, and biological molecules.