ion-exchange resin

ion-ex·change chro·ma·tog·ra·phy

(ī'on-eks-chānj' krō'mă-tog'ră-fē)

Chemical investigation in which cations or anions in the mobile phase are separated by electrostatic interactions with the stationary phase.
See also: anion exchange, cation exchange

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cat·i·on ex·change

(kat'ī-on eks-chānj')

The process by which a cation in a liquid phase exchanges with another cation present as the counter-ion of a negatively charged solid polymer (cation exchanger). Cation exchange may be used chromatographically, to separate cations, and medicinally, to remove a cation.
See also: anion exchange

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an·i·on ex·change

(an'ī-on eks-chānj')

The process by which an anion in a mobile (liquid) phase exchanges with another anion previously bound to a solid, positively charged phase, the latter being an anion exchanger. Anion exchange may also be used chromatographically, to separate anions, and medicinally, to remove an anion (e.g., Cl^-) from gastric contents or bile acids in the intestine.

ion-exchange resin

An ionizable synthetic substance, which may be acid or basic, used accordingly to remove either acid or basic ions from solutions. Anion-exchange resins are used to absorb acid in the stomach, and cation-exchange resins are used to remove basic (alkaline) ions from solutions.

See also: resin

ion-exchange resin

a high-molecular-weight, insoluble polymer of simple organic compounds with the ability to exchange its attached ions for other ions in the surrounding medium. They are classified as cation- or anion-exchange resins, depending on which ions the resin exchanges. Cation-exchange resins are used to restrict sodium absorption in edematous states; anion-exchange resins are used as antacids in the treatment of ulcers. Ion-exchange resins may also be classified as carboxylic, sulfonic, etc., depending on the nature of the active groups. Used in biochemical extractions and purifications.