Amperometry is an electroanalytical method that measures the electric current generated at an electrode while maintaining a constant potential.

The current produced is proportional to the concentration of the analyte, allowing for its detection and quantification.

Amperometry is used in the construction of chemical sensors.

For instance, L. C. Clark developed the first amperometric sensor to measure the concentration of dissolved oxygen in the blood. Encased within a gas-permeable membrane, this comprises a platinum cathode and silver-silver chloride anode in a potassium chloride solution as the electrolyte.

When a voltage between the cathode and anode is applied, the dissolved oxygen molecules diffuse across the membrane and undergo reduction at the cathode surface. The anode supplies the electrons for this reaction, generating an electric current proportional to the oxygen concentration in the sample.

Amperometry is also utilized in glucose biosensors for monitoring blood glucose.