Soxhlet extraction is widely used for many types of solid samples, especially biological and environmental samples. It has been used for a wide range of samples like soils, sediments, and animal and plant tissues. A wide variety of solvents like dichloromethane (DCM), pure or mixed with acetone or hexane, and acetone–hexane mixtures can be used.
The soxhlet extractor setup consists of a round bottom flask, siphon tube, distillation path, expansion adapter, condenser, cooling water inlet, cooling water outlet, heat source and thimble.
In this method, sample needs to be crushed, using a pestle and mortar, to provide a greater surface area. The sample material is packed in filter paper and placed in the thimble which is placed inside the Soxhlet extractor.
The solvent is heated using heating source like isomantle and will begin to evaporate, moving through the apparatus to the condenser. Due to heat the solvent in the bottom flask vaporizes into the condenser. The condensate then drips into the reservoir containing the thimble. Once the level of solvent reaches the siphon it pours back into the flask and the cycle begins again.
The advantage of Soxhlet extraction is that it can be extracted multiple times. Compared with the general soaking method, it has the advantages of small solvent dosage, high efficiency and complete extraction.
Soxhlet extraction
