Potentiometriska

Potentiometriska refers to potentiometry, a branch of electrochemistry focused on measuring the electrical potential of an electrochemical cell under negligible or zero current. Potentiometric measurements reveal the activity of specific ions in a solution and are commonly used to determine ion concentrations. The term covers instruments, electrodes, and methods that rely on a stable potential difference rather than significant current flow.

A typical setup uses a working electrode sensitive to the target ion, such as an ion-selective electrode, paired with a stable reference electrode. The resulting potential is read with a high-impedance voltmeter to minimize current draw. Potentiometric readings depend on the activity (not just concentration) of ions and are described by the Nernst equation, E = E0 + (RT/zF) ln a_i, where z is the ion charge and a_i its activity. At standard temperature, slopes near 59 mV per z unit are expected for monovalent ions. pH measurement with a glass hydrogen‑ion electrode is the most well-known potentiometric application.

Applications span analytical chemistry, environmental monitoring, clinical diagnostics, and process control. Potentiometric titration is a related technique that monitors potential changes to determine analyte concentration. Limitations include electrode selectivity, interference from competing ions, drift of reference electrodes, and the need for careful calibration and temperature control. Overall, potentiometriska approaches provide a direct, non-destructive means to quantify ionic species in many solutions.