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 ?
The haemoglobin chromatograms eluted from this anion-exchange column were converted with the conventional HPLC cation-exchange chromatography pattern.
Tris acetate buffer was previously used in our laboratory (with ICP-MS detection) to resolve and to quantitate four arsenic species (AsIII, AsV, DMA, and MMA) in drinking water on an anion-exchange column (15).
We found the direct immunoassay method to have a test sensitivity within the range reported for anion-exchange methods, and its application and usefulness are similarly dependent on other patient characteristics, in addition to alcohol intake.
3) Nonstandard abbreviations: SSD, sialic acid storage disease; ISSD, infantile sialic acid storage disease; NANA, N-acetylneuraminic acid (free sialic acid); HPAE-PAD, high-performance anion-exchange pulsed amperometric detection; tMS, tandem mass spectrometry; KDN, 2-keto-3-deoxy-D-glycero-D-galactonononic acid; IS, internal standard; ESI, electrospray ionization; MRM, multiple reaction monitoring; ERNDIM, European Research Network for Evaluation and Improvement of Screening Diagnosis and Treatment of Inherited Disorders of Metabolism; and LOD, limit(s) of detection.
Anion-exchange fractionation can be regarded as a replacement of the first-dimensional separation, isoelectric focusing, in the 2D-PAGE technology.
We used a HPLC system (Gulliver system with a JASCO PU-980 pump) equipped with a Finepak GEL SA-121 anion-exchange column [10 cm x 6.
The anion-exchange methods measure a mixture of isoforms, generally including the asialo-, mono-, di-, and all or part of the trisialo transferrins, and the total of these components is reported as CDT.
Incomplete elution of the CDT isoforms from the anion-exchange microcolumn can cause severe undermeasurement of CDT.
To prepare calibrators, human PCT (amino acids 1-115) was overexpressed in Escherichia coli and purified by anion-exchange and reversed-phase chromatography as described previously (14).
Here we report a GC/MS method for the quantification of serum estradiol in which estradiol is separated from the ether extract of serum samples by fractionation with a polystyrene divinylbenzene resin that has strong anion-exchange and adsorption properties.
Chromatographic columns were as follows: PRP-X100 anion-exchange columns (250 or 150 mm x 4.
Rapid separation of a CDT fraction comprising isoforms with two, one, or no sialic acids and part of that with three sialic acids by anion-exchange chromatography on minicolumns followed by RIA (CDTect [TM]) has become widely used (5).