What are the differences between anion exchange chromatography and cation exchange chromatography?

Question

Accepted Answer

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)

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)