Ion exchange chromatography operates through the reversible exchange of ions between the mobile phase and the stationary phase (resin).
Ion Exchange Mechanism
1) Equilibrium Process:
Ions in the mobile phase displace counter-ions on the resin based on their affinities until equilibrium is achieved.
2) Selectivity:
Differing affinities based on resin properties, ion types, and eluent conditions result in selective binding and separation.
3) Elution:
Bound ions are released by altering the mobile phase’s ionic strength or pH, allowing competitive displacement.
Binding and Exchange Examples
Cation Exchange Resin:
Anion Exchange Resin:
