Chromatography, chromatography techniques,ion exchange chromatography, elution based chromatography,types of chromatography,types of resin,ideal characteristics of resin, physical properties of resin, factors affecting ion exchange process, application of resin, elution of resin, regeneration of resin, Equilibration in ion exchange chromatography, application of ion exchange chromatography

1. ION EXCHANGE
CHROMATOGRAPHY

2. ION EXCHANGE CHROMATOGRAPHY:
>> Mixture of similar charged ions separated by
using ion exchange resin.
- IOC is a proces which allows the Separation of
ions and polar molecules based on the affinity to
the Ion Exchanger. For charged particles protein.
nucleotide,
- Cations or Anions can be separated
PRINCIPLE :
Reversible exchange of ions b/w ions present in
the solu. & ion exchange resin

4. According to the Source they can -
Natural :
Cation - Zeolytes, Clay
Anion - Dolomite
Synthetic Inorganic & Organic resins
Organic resins are polymeric resin matrix
The resin composed of -
Polystyrene (sites for exchangeable functional groups),
Divinyl benzene (Cross linking agent)-offers stability

5. lon exchange resin should have following
requirements :
>>It must be chemically stable
>>It should be insoluble in common solvents
>> It should have a sufficient degree of cross linking
>>The swollen resin must be denser than water
>>It must contain sufficient no. of ion exchange groups

7. d) Surface sulfonated & bonded
electrostatically with anion exchanger
>> less efficient & low exchange capacity
*PHYSICAL PROPERTIES OF ION EXCHANGE RESINS :
Cross linking:
It affects swelling & strength & solubility
Swelling:
When resin swells, polymer chain spreads apart
Polar solvents → swelling
Non-polar solvents → contraction
Swelling also affected electrolyte conc.

9. MECHANISM OF ION EXCHANGE PROCESS :
The ion exchangers behave as a porous network which
carries a surplus electric charge distributed over the
surface and throughout the pores. The surplus charge is
compensated by the ions of opposite charge.
When the ionization takes place, they are exchanged
with the ions which migrate into the solution. In this
process, chemical bonds are not formed but the
exchange occurs by the diffusion in two different
stages:

10. 1. Film Diffusion: Through an extremely thin film, there is
a diffusion of counter-ions through a surface liquid which
surrounds the ion exchanger. It is prominent in dilute
solutions and has smaller counter-ions. exchanger. It is
predominant at high concentration and with large ions.
This is
2. Particle Diffusion: It refers to diffusion of counter-ions
within the pores of ion
increased by exchangers with low degree of cross linking,
high exchange capacity,
small particle size, and counter-ions with low valency and
increasing temperature.

13. EQUILIBRATION
The first step is the equilibration of the
stationary phase to the desired start
conditions. When equilibrium is
reached, all stationary phase charged
groups are associated with
exchangeable counter-ions, such as
chloride or sodium, as shown by the
blue (counter ions) and red (stationary
phase charged groups) ions.

16. REGENERATION
The final step, regeneration, removes all molecules
still bound.
This ensures that the full capacity of the stationary
phase is available for the next run.

17. PRACTICAL REQUIREMENTS :
1. Column
>> glass, stainless steel or polymers
Length: diameter ratio 20:100 to 100:1
2. Packing the column
>> Wet packing method
3. Application of the sample
After packing, sample is added to the top of the
column, use syringe or pipette

18. 4. Mobile phase
Acids, alkalis, buffers...
5.Elution
Components of mixture separate & move down the
column at different rates depending upon the affinity
of the ion for ion exchanger.
>> the eluates are collected at different stages
6. Analysis of the eluate
> spectrophotometric, flame photometry
polarographic, conductometric...

22. FACTORS AFFECTING ION EXCHANGE :
a. Nature & properties of ion exchange resins
Cross linking & swelling is important
If more cross linking, they are more rigid, but
swelling is less
swells less→ separation of ions of different sizes is
difficult
b. Nature of exchanging ions
1. valency of ions

23. 2.Size of ions
3. Polarizability
4. Concentration of solution
5. Concentration & charge of ions
APPLICATIONS :
- Softening of water
- demeneralisation of water
- purification of solutions free from ionic
impurities
- separation of inorganic ions
- separation of sugars, amino acids
ion exchange column in HPLC