Soxhlet extraction

Principle

In Soxhlet extraction, target components of solid samples can be extracted by using a solvent in which they can be dissolved. The Soxhlet extractor is a device with a heater and the solvent container at the bottom, a tube holding a thimble (filter) with solid sample in the middle, and a condenser on the top.

When the solvent container is heated, the solvent evaporates and is condensed into liquid at the top condenser. Next, the solvent drips on the solid sample dissolves the solvent-soluble component, and then returns into the solvent container. Since the solvent-soluble component has a higher boiling point than the solvent, the solvent-soluble component gradually concentrates in the solvent container as this cycle is repeated. The solvent-insoluble component leaves inside the thimble filter.   

Principle of Soxlhet extraction

　　　　　　　　　　　　　　　Fig.1　Principle of Soxlhet extraction

Applications

• Extraction of resin contained in paper
• Measurement of toluene insoluble matter
• Extraction of dioxins, PCBs etc.
• Measurement of plastic content ratio in products