Application Note Environmental Soxhlet Extraction

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The Soxtherm Family

Soxtherm Accessories - Beakers, Thimbles and Holders, Tongs and Seals

Soxhlet is used widely in the analysis of air, soil and water from the determinations of analytes such as oil & grease, PCB, PAK, TEM, air filters, dioxins and many more.

Normally a solid material containing some of the desired compound is placed inside a "thimble" made from thick filter paper, which is loaded into the main chamber of the Soxhlet extractor. This solid material may be air filters, soil or in the case of water, filtered material.

The Soxhlet extractor is placed onto a flask containing the extraction solvent. For environmental analysis a very wide range of solvents may be used with a wide degree of boiling points. The most common solvents used are Dichloromethane, Ether, Toluene or Acetone. The hotplate temperature must be regulated according to the solvent used. The Gerhardt Soxtherm rapid Soxhlet system can be programmed for use with virtually all solvents used in environmental analysis.

The solvent is heated on a hotplate to reflux. The condenser ensures that any solvent vapour cools and drips back down into the chamber housing the solid material. Some of the desired compound will then dissolve in the solvent.

During each cycle, a portion of the non-volatile compound dissolves in the solvent.

After extraction the solvent is removed yielding the extracted compound. The non-soluble portion of the extracted solid remains in the thimble, and is usually discarded.

By immersing the sample in hot solvent the Soxtherm extracts materials much quicker than in a traditional cold extraction. The solvent is recirculated to rinse the extractable material into the bottom of the beaker. Finally the solvent is removed by evaporation automatically and recovered for safe disposal or reuse.

The Soxtherm has proved to be a fast, efficient and safe method of Soxhlet extraction for many hundreds of laboratories all over the World.

The latest development in the Soxtherm is the ability to control multiple units from a PC using Soxtherm Manager.

Gerhardt supply both traditional and automated extraction systems that can be viewed on our product pages by clicking the links.

For a list of available methods or if you would like more information on Soxhlet extraction of your sample please click on the links below.

For more information on other Soxhlet extractions - click here.

For more information on Gerhardt Traditional Soxhlet Equipment - click here.

For more information on Gerhardt SOXTHERM Extraction unit - click here.