Chromatography is a laboratory technique used to separate, identify, and sometimes quantify the components of a mixture. It is based on the different rates at which substances move through a medium under the influence of a solvent or carrier.
Key Points:
- Purpose:
- To separate mixtures into individual components.
- To identify substances in a mixture.
- To sometimes measure the amount of a substance (quantitative analysis).
- Principle:
- Components in a mixture move at different speeds through a stationary medium (solid or liquid) when a solvent (mobile phase) flows through it.
- This differential movement allows the substances to separate.
- Types of Chromatography:
- Paper chromatography: Separation of pigments or small molecules on paper.
- Thin-layer chromatography (TLC): Uses a thin layer of silica or alumina on a plate.
- Column chromatography: Separation in a vertical column filled with solid adsorbent.
- Gas chromatography (GC): Uses gas as the mobile phase for volatile compounds.
- High-performance liquid chromatography (HPLC): High-pressure method for precise separation in liquids.
- Applications:
- Identifying plant pigments, amino acids, or drugs.
- Purifying chemicals in research and industry.
- Testing food additives and contaminants.
In short: Chromatography is a method to separate and study the components of a mixture based on how differently they move through a medium.