Soxhlet Extractor

This method involves bringing a material to be extracted (usually in solid form) into contact with the extraction solvent for a period of time, followed by separation of the solution from the solid debris.

In this method, the material to be extracted is placed in a ‘thimble’ made of cellulose or cloth in a central compartment with a siphoning device and side-arm both connected to a lower compartment. The solvent is placed in a lower compartment and a reflux condenser is attached above the central sample compartment.  Each components of the set up is a separate item of glassware which is assembled together with the appropriate contents, to make the complete apparatus.

The solvent in the lower container (usually a round bottom flask) is heated to boiling and the vapour passed through the side-arm up into the reflux condenser. Here the vapour liquefies and drips into the thimble containing the material to be extracted. The warm solvent percolates through the material and the wall of the thimble and the extracts gradually collects in the central compartments. Once the height of the extract reaches the top of the siphon, the entire liquid in the central compartment flows through this and back into the lower solvent container. The process is then repeated.