Mechanism of Ion Exchange Process

• 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

1. Cation Exchange Resin:

2. Anion Exchange Resin: