#SOXHLET EXTRACTOR SERIES#

The conservation of the solvent, the continuous nature of the extraction, and the ability to accommodate large sample sizes makes Soxhlet extraction ideal for isolating organic compounds from large portions of insoluble material. Thus, the cycle can repeat indefinitely without loss of solvent. The lipid extract continually collects in the flask, whereas the solvent becomes part of the next extraction cycle. The solution level never exceeds the top of the thimble, so no solid enters the flask. When the siphon is full, the solution flows back into the flask. As the chamber fills, the siphon fills as well. Upon condensing, the solvent collects in the chamber, dissolving some of the organic material in the thimble. The solvent vapor rises through the distillation path in the Soxhlet apparatus to the condenser. The extraction is aided by the addition of energy in the form of heat, known as refluxing. The solid to be extracted is placed in a thimble in the central chamber of the apparatus. It will illustrate Soxhlet extraction of lipid biomarkers from marine sediment for use in paleothermometry and will introduce a few other applications of Soxhlet extraction in Earth science and chemistry.Ī typical assembly uses a round-bottomed flask, a cold water condenser, and the Soxhlet apparatus itself.

#SOXHLET EXTRACTOR SERIES#

This video is part of a series on lipid extraction, purification, and analysis from sediments. The Soxhlet extractor, invented in the 1870's by Franz von Soxhlet, allows automated, batch extraction from a solid, increasing the overall efficiency while using a small amount of solvent. To obtain a suitable amount of a biomarker for standard preparation, a large volume of sediment must be extracted. Large quantities of standard are needed to assess the performance of an instrument over time. Standards of these compounds must therefore be prepared from natural samples. Many of the compounds relevant to paleoclimatic studies are not available to purchase from retail scientific companies. Soxhlet extraction is a method of isolating compounds, such as lipids, from a large amount of solid material with a relatively small volume of solvent. Soxhlet extraction is often used for the extraction of larger (>10 g) samples. This chamber is set with a recirculator, and when a certain volume is reached (generally a volume large enough to submerge the whole sample), the chamber is flushed back into the round-bottomed flask via a built-in siphon, where the lipid extract accumulates while the solvent becomes part of the next cycle. When the gaseous solvent contacts the coil, it condenses into a chamber with a glass fiber thimble holding the sample. Solvent is refluxed from a round-bottomed flask upward into a condenser with a recirculating cold-water coil.

Modern Soxhlets use sophisticated blown glass condensers and organic solvents in this 'continuous' extraction method ( Figure 2). Archeological evidence from Mesopotamia places the use of a Soxhlet-like device that utilized hot water at ~3,500 BC 1,2. Soxhlet extraction is likely the oldest form of organic matter extraction. Red stars reflect those that are not accurate indicating that the instrument requires corrective maintenance.

Green stars represent standards that are accurate. Each star is a weekly measurement of the chemical standard. The dashed line represents a 1:1 relationship between the accepted and measured (on the instrument) value of a variable. Schematic depicting how chemical standard tracks the performance of an instrument through time. In these circumstances, a Soxhlet extraction is used.įigure 1. The Accelerated Solvent Extraction (Dionex) and sonication extractions are not appropriate for the extraction of such large sediment volumes. Therefore, these compounds need to be extracted from natural samples, and because of the large volumes of standards required, large volumes of sediment need to be extracted. However, some compounds that occur in nature and that are relevant to paleoclimatic studies have not yet been isolated and purified for purchase. Many chemical standards can be purchased from retail scientific companies, like Sigma-Aldrich and Fisher. Because standards must test the performance of instruments over a long period of time, large volumes of the standards are often required. Source: Laboratory of Jeff Salacup - University of Massachusetts AmherstĮvery lab needs standards that track the performance, accuracy, and precision of its instruments over time to ensure a measurement made today is the same as a measurement made a year from now ( Figure 1).