Amperometry

Amperometry is an electrochemical technique used to measure the current that develops in an electrochemical cell under conditions where the potential (voltage) is held constant. This method is primarily used to determine the concentration of a specific analyte in solution by measuring the current produced as the analyte undergoes a redox reaction at the surface of an electrode.

Principles

Amperometry is based on the principle that the current flowing through an electrochemical cell is proportional to the rate of the redox reaction occurring at the electrode surface. The electrode potential is controlled using a potentiostat, which maintains the working electrode at a constant potential relative to a reference electrode. The current measured is typically a result of the oxidation or reduction of the analyte, which is directly proportional to its concentration in the solution.

Applications

Amperometry is widely used in various applications including:

• Environmental monitoring, for detecting pollutants in water and air.
• Clinical chemistry, for the measurement of glucose levels in blood using glucose sensors.
• Food and beverage industry, for quality control and determination of certain compounds.
• Pharmaceutical industry, for drug analysis and quality control.

Amperometric Sensors

Amperometric sensors, such as the Clark electrode for oxygen measurement, are specific types of electrodes used in amperometry. These sensors are designed to respond to a particular analyte by producing a current proportional to the concentration of the analyte. They are widely used in biomedical applications, environmental monitoring, and industrial process control.

Advantages and Limitations

Amperometry offers high sensitivity and specificity, making it suitable for trace analysis of substances. However, the technique can be affected by the presence of other oxidizable or reducible substances in the sample, which can interfere with the measurement. Additionally, the electrodes used in amperometry may require frequent calibration and maintenance to ensure accuracy.

See Also

• Voltammetry
• Electrochemistry
• Bioelectrochemistry
• Analytical chemistry