Anion exchange chromatography????

Question

Can anyone please explain the principle of anion exchange chromatography?

Answer 1

An ion exchanger consists of an insoluble matrix to which charged groups have been covalently bound. The charged groups are associated with mobile counter-ions. These counter-ions can be reversibly exchanged with other ions of the same charge without altering the matrix.

The matrix maybe based on synthetic resins, cellulose or Sephadex. An anion exchange has a positively charged matrix (AE-, DEAE- or QAE-) and negatively charged counter-ion (OH, Cl).

A good example of anion exchange chromatography is the separation of proteins by DEAE-Sephadex column. Proteins have both positively and negatively charged groups. When a solution of mixed proteins is applied to a DEAE-Sephadex column, the negatively charged groups of proteins bind to the column, replacing the Cl counter-ion. The column is then eluted with a NaCl gradient, and the proteins will be separated according to their charges. The weakest anionic protein will come out first.

Answer 2

hahah oh man i just did an ion exchange chromatography lab yesterday (lonnggg :( )what is it that you exactly need to know? - essentially you have two columns with resins inside: a cation(strongly acidic) column and an anion(weakly basic) column. these two exchange columns are used to deonize a solution containing both cations and anions. you take the pH of this solution, pass it through the cation column and take the pH again. then you pass it through the anion column and take the pH again. The columns will separate ions of like sign and you will see the columns change colour. usually your solution will contain four ions - two that will be more weakly bound to the resin and two that will be more strongly bound to the resin (one for each cation and anion). these you can separate by filtering weak and strong acids through to separate them (at which point it should return the original colour). Essentially its used to show how Ion-Exchange Chromatography (in greek 'colour writing') can separate both cations and anions from a mixture.