Jonoselektywna

Jonoselektywna is an adjective used to describe a material, membrane, electrode, or sensor that shows preferential response to a specific ion in the presence of others. In analytical chemistry, jonoselektywne elements are central to ion-selective electrodes (ISEs), which convert ion activity into an electrical signal.

The mechanism relies on a membrane that is selective for the target ion. The electrode potential depends mainly on the activity of that ion, following the Nernst equation. Slopes near 59 mV per decade of activity changes are expected for monovalent ions at room temperature, with different values for multivalent ions. Selectivity arises from the membrane composition and can involve ionophores—molecules that bind selectively to a particular ion—as well as glass, polymer matrices, or inorganic crystals. The overall response is assessed using selectivity coefficients that describe the influence of interfering ions.

Common jonoselektywne sensors include pH electrodes (hydrogen ion selective), fluoride ion electrodes, chloride ion electrodes, and potassium or sodium ion electrodes. The choice of membrane material and ionophore determines the range of measurable analytes, response time, detection limit, and resistance to fouling or drift.

Applications span environmental monitoring, clinical analysis, food and beverage testing, and industrial process control. Advantages of jonoselektywne sensors include rapid, in situ measurements, portability, and minimal sample preparation, while limitations involve potential interferences from similar ions, drift over time, and calibration requirements.

See also: ion-selective electrodes, ionophores, membrane technology, analytical chemistry.