jonselektiva

Jonselektiva refers to materials, membranes, and devices that respond predominantly to a single ion species in a mixture, enabling selective detection, transport, or separation. The term is used across chemistry, electrochemistry, biology, medicine, and environmental analysis. In practice, jonselektiva are realized as ion-selective sensors and membranes designed to favor one ion over others.

The selectivity arises from specific interactions between the target ion and the sensing element. This can involve ionophores or ionophores embedded in a membrane, fixed charged sites that attract or repel particular ions, or size and charge complementarity that make certain ions energetically more favorable to interact with the device. In ion-selective electrodes, a membrane such as glass or a polymeric layer mediates the response, producing a potential that correlates with the activity of the target ion.

Common implementations include pH-sensitive glass electrodes for hydrogen ions, Na+- and K+-selective membranes for alkali metals, and Ca2+- or Cl−-selective sensors for divalent cations and anions, respectively. The performance of jonselektiva is described by selectivity coefficients, and relationships like the Nicolsky–Eisenman equation help account for interfering ions.

Applications span environmental monitoring (water quality), clinical electrolyte analysis, industrial process control, agriculture, and food and beverage testing. Limitations include interference from ions with similar charge or size, dependence on ionic strength, pH, and temperature, and the need for regular calibration and drift compensation. Ongoing research focuses on new ionophores, solid-state membranes, and multiplexed sensing platforms to expand selectivity and robustness.