Basis of differentiation

Anion exchange chromatography 

Cation exchange chromatography 

Definition

Anion exchange chromatography separates molecules that carry negative charges

Cation exchange chromatography separates molecules with positive charges 

Binding mechanism

Attraction between anions and positively charged groups on the resin

Attraction between cations and negatively charged groups on the resin

Ion Exchange Resin

Examples include quaternary ammonium compounds

Examples include sulfonic acid groups

Optimal pH range

Proteins bind to anion exchange resins when the pH is above their isoelectric point (pl)

Proteins bind to cation exchange resins when the pH is below their isoelectric point (pI)