Polarography

Polarography is an electroanalytical technique that identifies or measures substances by recording current as a function of applied voltage, traditionally with a dropping mercury electrode.

Dropping mercury electrode: A working electrode formed by mercury drops that grow and detach at a capillary tip. Renewed mercury drops provide a reproducible surface for recording polarographic waves.
Jaroslav Heyrovský: A Czech chemist who discovered polarography and received the 1959 Nobel Prize in Chemistry. His experiments established the method and its characteristic current–potential curves.
Trace metal analysis: The determination of very low concentrations of metallic elements in materials and environmental samples. Polarographic currents can quantify reducible metal ions at low concentrations.
Voltammetry: A family of electroanalytical methods that measure current while varying an electrode potential. Polarography is a historically defined form of voltammetry distinguished by its mercury drop electrode.
Polarographic wave: A sigmoidal current–potential response produced as an electroactive species is reduced or oxidized at an electrode. Its half-wave potential and limiting current supply characteristic analytical information.
Nobel Prize in Chemistry: An annual international award recognizing outstanding contributions to chemistry. Heyrovský’s 1959 award recognized his discovery and development of polarographic methods.
Oxygen determination: Measurement of dissolved oxygen concentration in a liquid sample. Oxygen reduction at a mercury electrode provides a current related to dissolved oxygen.
Linear sweep voltammetry: A voltammetric method that scans electrode potential linearly while recording current. It uses a potential sweep like polarography but does not require a dropping mercury electrode.
Half-wave potential: The electrode potential at which a polarographic wave reaches half its diffusion-limited current. Its value helps distinguish electroactive species under specified solution conditions.
Mercury electrode: An electrode that uses liquid mercury as its electrochemically active surface. Polarography developed from the use of renewable mercury surfaces in electrochemical analysis.

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PotentiometryCompared with: Its current–voltage response contrasts with potentiometry’s open-circuit voltage measurement.