potentiometriin

Potentiometry is a branch of analytical chemistry concerned with measuring electrical potentials. Specifically, it involves measuring the potential difference between two electrodes in an electrochemical cell. This potential difference can be related to the concentration of a specific ion or species in solution through the Nernst equation.

In a potentiometric measurement, one electrode is typically a reference electrode with a stable, known potential, such as a saturated calomel electrode or a silver/silver chloride electrode. The other electrode is the indicator electrode, whose potential varies with the concentration of the analyte of interest. For example, a glass electrode is commonly used to measure hydrogen ion concentration (pH).

When the indicator electrode is immersed in the solution containing the analyte, an electrochemical reaction occurs at its surface. This reaction results in a potential difference between the indicator electrode and the reference electrode. This potential difference is measured using a high-impedance voltmeter. By calibrating the instrument with solutions of known analyte concentrations, the concentration of an unknown sample can be determined. Potentiometry finds applications in various fields, including environmental monitoring, clinical diagnostics, and industrial process control.