Affinity chromatography is a technique used to separate and purify specific biomolecules, such as proteins or nucleic acids, based on their unique interactions with a particular ligand. In this method, a solid support, often a column filled with beads, is coated with a ligand that specifically binds to the target molecule. When a mixture is passed through the column, only the desired biomolecule will attach to the ligand, while other components are washed away. After the target molecule is bound, it can be eluted, or released, from the column by changing the conditions, such as altering the pH or adding a competing substance. This allows for the collection of a highly purified sample. Affinity chromatography is widely used in biochemistry and molecular biology for applications like protein purification and antibody isolation, making it an essential tool in research and biotechnology.