ion 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, nonmobile, positively charged phase, the latter being an anion exchanger. For example, the process takes place when Cl- is exchanged for OH- in desalting. The reaction is Cl- (in solution) + (OH- on anion exchanger+) → (Cl- on anion exchanger) + OH- (in solution); in combination with the cation exchange, NaCl is removed from solution. Anion exchange may also be used chromatographically, to separate anions, and, medicinally, to remove an anion (for example, Cl-) from gastric contents or bile acids in the intestine.

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

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

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

A reversible chemical reaction in which ions in a solution are replaced by others with like charge from an insoluble solid such as an ION EXCHANGE RESIN. The process is used for softening hard water, purifying sugar, separating radioactive isotopes and for other purposes.
References in periodicals archive ?
Incomplete elution of the CDT isoforms from the anion-exchange microcolumn can cause severe undermeasurement of CDT.
The mobile phase for anion-exchange chromatography (PRP-X100; 150 x 4.1 mm) was a mixture of 20 mmol/L N[H.sub.4]HC[O.sub.3] at pH 9.5, adjusted with aqueous ammonium hydroxide, and methanol (7:3 by volume).
In routine methods, the transferrin isoforms are separated into two fractions by anion-exchange chromatography on microcolumns and the CDT fraction quantified by RIA (CDTect) or immunoturbidimetry (%CDT-TIA; Axis).
The LC-MS/MS PBG method was compared with both a qualitative modified Watson-Schwartz method (n = 146) and a quantitative anion-exchange column method from Bio-Rad Laboratories (n = 100) based on the method of Mauzerall and Granick (12).
IEF is suitable for visualization of Tf isoform patterns in the anion-exchange microcolumn eluates of (commercial) CDT tests.
3); (b) the column effluents after application of the iron-treated serum samples to the top of the anion-exchange microcolumns; (c) the column effluents after the columns were rinsed with 1.5 mL of elution buffer (Fig.
Separation of PSA-API from PSA-ACT by anion-exchange chromatography (Fig.
Initial attempts to utilize the same anion-exchange extraction using the Bond-Elut SAX (Varian) column used in the MMA assay were unsuccessful, probably because an amino group is present in gabapentin.
The aim of our study was to investigate a widely distributed commercially available set of reagents, CDTect-RIA, for reliability of the initial anion-exchange isotransferrin fractionation step involved in the determination of CDT.
The identification of the serum protein bound to As species was therefore carried out on an anion-exchange column (MonoQ 16/10, Pharmacia) because this column shows a high resolution for the separation of serum proteins.
After iron saturation of the serum samples, isolation of transferrin isoforms with pIs [greater than or equal to] 5.7 (asialo-, monosialo-, and disialotransferrin) is accomplished by anion-exchange chromatography on microcolumns.
DE-53 anion-exchange cellulose (25 g) was suspended in 300-400 mL of [H.sub.2]O, allowed to settle, and the fines decanted two or three times.