Potensiometriin

Potensiometriin is a measurement technique used in analytical chemistry to determine the concentration of a specific ion in a solution. It relies on measuring the electrical potential difference between two electrodes immersed in the solution. One electrode is typically a reference electrode with a stable and known potential, while the other is an indicator electrode that selectively responds to the ion of interest.

The potential difference between these electrodes is directly related to the concentration of the target ion, according to the Nernst equation. This equation establishes a logarithmic relationship between the electrode potential and the ion concentration. By calibrating the indicator electrode with solutions of known ion concentrations, a calibration curve can be constructed. Subsequent measurements of unknown solutions can then be compared to this curve to determine the unknown concentration.

Potentiometric measurements are non-destructive, meaning the sample is not consumed during the analysis. This makes it a valuable technique for analyzing precious or limited samples. The method is relatively simple to perform, requires minimal sample preparation, and can be automated. Common applications include water quality monitoring, food analysis, and clinical diagnostics. The accuracy of potentiometric measurements depends on factors such as electrode calibration, temperature stability, and the presence of interfering ions.