Ion exchange chromatography separates ions and polar molecules based on their affinity for an ion exchanger. There are two main types: cation exchange attracts positively charged molecules to a negatively charged resin, while anion exchange attracts negatively charged molecules to a positively charged resin. The stationary phase is an ion exchange resin and the mobile phase is usually a liquid or gas that carries sample components through the resin. The process involves equilibrating the resin, adsorbing the sample so charged molecules bind to the resin, then eluting bound molecules by increasing ionic strength so they detach from the resin in a purified form.