Ion exchange chromatography is a technique used to separate charged molecules like proteins, peptides, amino acids, and nucleotides. It works by exchanging ions between a stationary ion exchange resin and a mobile phase liquid. There are two main types of ion exchange resins - cation exchangers that attract positively charged ions, and anion exchangers that attract negatively charged ions. Ion exchange chromatography is useful for purifying solutions, extracting enzymes, softening water, and separating molecules like sugars, amino acids, and proteins.

2. Introduction:
Ion exchange chromatography is a technique used to separate the ionisable
molecules or charged molecules present in a mixture by the difference in their net
charge using the stationary phase(ion-exchangers) and the mobile phase(salt
solution or buffer solution).
Very commonly used to separate charged biological molecules such as: proteins,
peptides, amino acids, nucleotides, etc.

3. Principle:
Ion exchange chromatography is based on the principle of Exchange of ions.
Cat-ion exchanger
• It have negatively charged
exchanger and it will attract
positively charged cat-ions.
• It also called as ‘acidic ion
exchange’, then resin become cat-
ion exchanger.
• [X⁻ + R⁺ Cl⁻ → X⁻R⁺ + Cl⁻]
• Ex. Sulphonic acid → strong cat-
ion exchanger.
• Carboxylic acid → weak cat-ion
exchanger.
Positively charged analyte
(cat-ion) attracted to
Negative surface
An-ion exchanger
• It have positively charged
exchanger and it will attract
negatively charged an-ions.
• It also called as ‘basic ion
exchange’, then resin become an-
ion exchanger.
• [X⁺ + R⁻K⁺ → X⁺R⁻ + K⁺]
• Ex. Tertiary amines → strong an-
ion exchanger.
• Secondary amines → weak an-ion
exchanger.
Negatively charged analyte
(an-ion) attracted to
Positive charge
Cat-ion exchanger
(stationary phase
particles)
+
An-ion exchanger
(stationary phase
particles)
-

5. Types of resins:
• Natural resins • Synthetic resins
Cat-ion An-ion
Clay,
zeolyte
Polymeric
resin
matrix
Inorganic
resins
Organic
resins
Dolomite

6. Instrumentation:

7. Properties of ion-exchange chromatography:
Properties of Ion-exchange chromatography depends upon:
>) its composition.
>) functional group.
>) exchangeable ions.
>) porosity.
>) particle size.

8. Factors affecting Ion-exchange chromatography:
1) Size of ions:
For similar charged ions, exchange increases with decrease in the size of hydrated ion.
Ex. ( Li<H⁺<Na⁺<NH⁺<K⁺<Rb⁺<Cs⁺).
2) Concentration of solution:
In dilute solution polyvalent anions are generally adsorbed preferentially.
3) Concentration and charge of ions:
If resin has higher positive charge and solution has lower positive charge is favoured at
high concentration ,and vice-versa.

9. Applications of IEC:
>) It is helpful in extraction of enzymes from tissues.
>) It is used for softening and demineralisation of water.
>) Purification of solution free from ionic impurities.
>) It is used in separation of inorganic ions.
>) It is used in separation of sugars, amino acids, and proteins.