Elektroanalys

Elektroanalys is a branch of analytical chemistry that uses electrical signals to quantify chemical species and to study redox properties. Core techniques include voltammetry, amperometry, chronometry, potentiometry, conductometry, coulometry, and electrochemical impedance spectroscopy. Voltammetry methods control the potential of a working electrode versus a reference electrode and measure the resulting current; techniques include cyclic voltammetry, linear sweep voltammetry, differential pulse voltammetry and square wave voltammetry. Amperometry and chronometry monitor current at a fixed potential over time, useful for reaction kinetics and sensor measurements. Potentiometry measures a potential difference between a working and reference electrode to determine activity of ions, as in ion-selective electrode measurements. Conductometry and coulometry relate to solution conductivity and total charge passed during electrolysis, respectively. Electrochemical impedance spectroscopy characterizes the frequency-dependent impedance of an electrochemical cell, providing information on charge transfer and diffusion processes.

Typical instrumentation includes a three-electrode cell (working, reference, counter) and a potentiostat or galvanostat to control potential or current. Common electrode materials include glassy carbon, platinum, gold, and carbon fibers; reference electrodes include Ag/AgCl or saturated calomel electrodes. Applications span environmental monitoring (trace metals, pollutants), clinical and pharmaceutical analysis (drug monitoring, biosensors), food quality, corrosion science, and process control. Elektroanalys offers high sensitivity, rapid response, potential for miniaturization, and compatibility with in situ measurements. Limitations include electrode fouling, interferences from complex matrices, need for careful calibration, and the requirement that the analyte participate in an electrochemical process. A historical foundation lies in Faraday's laws of electrolysis in the 1830s, with continued development of methods such as cyclic voltammetry in the 20th century.