This document discusses different chromatography techniques used to separate proteins and molecules, including: 1) Ion-exchange chromatography uses resins with attached ions that provide a positive or negative charge to separate molecules based on their charge. 2) Gel-filtration chromatography can be used to separate proteins based on their size and molecular weight. 3) Affinity chromatography separates molecules based on their ability to bind specifically to antibodies or other ligands attached to resins. 4) Fast-performance liquid chromatography is commonly used and pumps samples through columns for high-resolution separation of proteins and other molecules.