Ion exchange chromatography separates ions based on their equilibrium with counter-ions on the stationary phase. It allows separation of ions on low-capacity columns. Charged compounds bind to the oppositely charged exchanger, while neutral or same-charged compounds pass through. Binding is reversible, and adsorbed ions are eluted using a gradient. Ion exchange media come in diverse particle sizes, ionic forms, and purity levels. This technique is widely used to purify proteins and other charged molecules from aqueous solutions, providing high matrix tolerance and predictable elution.