lamperometria

Lamperometria, or lamperometry, is an electrochemical analytical technique in which the current arising from redox processes at a working electrode is monitored as a function of time under a fixed potential or after a potential step. The method is a variant of amperometry and chronoamperometry and is used to determine electroactive species in solution by relating current-time responses to analyte concentration and transport processes.

Principle and instrumentation: A potentiostat applies a defined potential between a working electrode and a reference electrode in contact with the sample, with a counter electrode completing the circuit. The resulting current is measured, typically under diffusion-limited conditions. The current-time response reflects the rate at which analyte molecules reach the electrode surface and undergo oxidation or reduction, and can be analyzed to quantify the analyte after calibration. In flow systems, lamperometry is often coupled with flow injection analysis or HPLC as a selective detector.

Applications: Widely used for rapid, sensitive detection of electroactive species such as ascorbic acid, catecholamines, phenols, or metal complexes; also used in enzymatic assays where an electroactive product is formed. The method is valued for its simplicity, fast response, and compatibility with continuous-flow formats.

Advantages and limitations: Advantages include direct measurement, low instrumentation complexity, and suitability for automated analyses. Limitations involve sensitivity to solution viscosity, interference from other redox-active species, electrode fouling, and the requirement that the analyte be electroactive or chemically converted to an electroactive species.

See also: Amperometry, Chronoamperometry, Voltammetry, Electrochemical detection.