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accelerated solvent extraction

in other name accelerated solvent extraction, abbreviated as ASE, a sample preparation technique in determination of POP (Persistent Orcanic Pollutants) that combines elevated temperature and pressure with solvents to achieve fast and efficient removal of components of interest from any solid sample (soil, sediment, food, textile, waste, biological sample, ash, etc.). The solubility of compounds is enhanced at elevated temperature, e.g. rising the temperature from 50 °C to 150 °C the solubility of anthracene is increased 13 fold resulting in enhanced diffusion as well. The high pressure makes it possible to work on temperatures above the boiling point of the solvent and helps to the solvent to enter into the pores of the sample. ASE has been demonstrated to be equivalent to existing extraction methodologies, such as Soxhlet extraction. (Source: MOKKA database, sheet No. 582)


method to separate components based on their relative solubilities (partition) in two different, immiscible solvents. In extraction" target="_blank">liquid/liquid extraction the solvent (usually organic) dissolves only the desired compounds from the sample solution (usually aqueous solution). In supercritical extraction the solvent is supercritical carbon dioxide. Soxhlet extraction is the tradional way for extracting solid samples, when the sample is connected with freshly boiled solvent in a special apparatus several times. The extraction of soild samples can be intensified by ultrasound (sonication assisted extraction, SAE) or elevated pressure and temperature (pressurized fluid extraction or accelerated fluid extraction, ASE). The solid phase extraction (SPE) is characterized by decreased sample and solvent need. Further miniaturization resulted in solid phase microextraction (SPME), stirbar+extraction and the membrane assisted extraction (MASE) techniques used for sample preparation for chromatography.

extraction from soil by organic solvents

solvent extraction uses an organic solvent as an extractant to separate organic and metal contaminants from soil. The organic solvent is mixed with contaminated soil in an extraction unit. The extracted solution then is passed through a separator, where the contaminants and extractant are separated from the soil. Organically bound metals may be extracted along with the target organic contaminants.

extraction from soil by solvents

solvent extraction from soil uses an organic solvent as an extractant to separate organic and metal contaminants from soil. The organic solvent is mixed with contaminated soil in an extraction unit. The extracted solution then is passed through a separator, where the contaminants and extractant are separated from the soil. Organically bound metals may be extracted along with the target organic contaminants.

extraction of LDNAPL from soil
groundwater extraction plant
liquid/liquid extraction

an extraction technique (LLE) in which one liquid is shaken with or contacted by an extraction solvent to transfer molecules of interest into the solvent phase. Typical sample preparation (concentration) method e.g. organic contaminants in water are extracted into an organic solvent to be measured by gas or liquid chromatography.

membrane assisted solvent extraction
chemical extraction using polypropylene membrane filled with organic solvent and placed into the aqueous sample. Sample preparation method for chromatography based on liquid/liquid extraction procedure where the phases are separated by the membrane. It can be fully automated. Typical applications: extraction of extractable hydrocarbons (EPH), PAHs, phenols, PCBs, pesticides from water or aqueous suspensions. Suitable for analytes to be extracted from extremely dirty matrices. (Source: B. Hauser, M. Schellin, and P. Popp: Membrane-Assisted Solvent Extraction of Triazines, Organochlorine, and Organophosphorus Compounds in Complex Samples Combined with Large-Volume Injection-Gas Chromatography/Mass Spectrometric Detection. Anal. Chem. 76, 6029-6038, 2004)
Micro Extraction by Packed Sorbent
sample preparation method for chemical analysis, e.g. for chromatography, abbreviated as MEPS. In principle it is a solid phase extraction (SPE) technique in miniaturized form: needs less sample, less solvents. The MEPS cartridge contains 2-3 mg solid packing, which can be C2, C8, C18, ion-exchange or unmodified silica phase. The MEPS cartridge is built into the syringe (of 10-250 microliters) needle. Pumping the sample through the cartridge the target compounds can be adsorbed on the stationary phase. Washing with solvent the interfering matrix components can be removed, the analyte concentrated can be eluted into LC or GC. Typical applications: determination of PAHs, pesticides, PCBs in volume-limited aqueous samples. (Source: www.labhut.com/docs/static/autosamplers/meps.pdf)
microwave extraction
chemical extraction assisted by microwave energy, can be used e.g. for extracting contaminants from soil prior to analysis. The process is faster than the conventional extraction methods, more economic as the cost of solvents is reduced, more environmental friendly due to the lower solvent need. The equipment is expensive but thousands of extractions can be carried out. The parameters are controlled by software resulting in good reproducibility.
multi-phase extraction of contaminated soil

multi-phase extraction uses a vacuum system to remove various combinations of contaminated groundwater, separate-phase petroleum product, and vapors from the subsurface. The system lowers the water table around the well, exposing more of the formation. Contaminants in the newly exposed vadose zone are then accessible to vapor extraction. Once above ground, the extracted vapors or liquid-phase organics and ground water are separated and treated.

Source: US-EPA, Clu-In:http://www.clu-in.org/techfocus/default.focus/sec/Multi-Phase_Extraction/cat/Overview/

protected water extraction plant
soil extraction
soil gas and vapour extraction and its treatment on the surface
soil gas extraction
soil vapour extraction: SVE

soil vapor extraction SVE is used to remediate unsaturated vadose zone soil. A vacuum is applied to the soil to induce the controlled flow of air and remove volatile and some semivolatile organic contaminants from the soil. SVE usually is performed in situ; however, in some cases, it can be used as an ex situ technology.

solid phase extraction

a chromatographic technique used to prepare samples for subsequent analysis, an effective method to concentrate or isolate the non-volatile analytes. It is a kind of column chromatography. The extract is eluted through the column (cartridge) containing the preconditioned sorbent by applying vacuum. The substance of interest is retained on the column and all the interfering components are eluted or the interfering components are retained and the substance of interest is eluted. This sample preparation technique is suitable for any compounds. The low solvent need, no need of concentration by evaporation and in this way avoiding the concentration of the polluting components, cheap sorbents, saving time, no emulsion formation, enhanced selectivity and potential for automatization are the advantages of SPE over the traditional liquid/liquid extraction (LLE).

solid phase microextraction
chemical extraction performed with a fiber coated with an extracting phase (solid or liquid). The coated fibers (with 5-10 micrometer coating) are used to isolate and concentrate analytes into the coating material. In the case of volatile compounds the fiber is kept in the headspace, in the case of non-volatile analytes the fiber is kept in the liquid to reach the equilibrium. After extraction, the fibers are transferred, with the help of the syringe-like handling device, to analytical instruments for separation and quantification of the target analytes. Desorption is performed by heat (gas chromatography) or by elution (liquid chromatography). The concentration in the coating of the fiber is proportional with that in the sample. The extraction is fast, easy to be automated, simple, can be done without solvents, and detection limits can reach parts per trillion (ppt) levels for certain compounds.
sonication assisted extraction

a physical technique employing ultrasound to intensely vibrate a sample media in extracting solvent and to maximise solvent/analyte interactions. Abbreviated as SAE, widely used for extracting the contaminants from soil.

Soxhlet extraction

an extraction technique of solids in which the sample is repeatedly contacted with solvent over several hours, increasing the extraction efficiency. Soxhlet extraction is a purification technique developed by Franz von Soxhlet in 1879. The solid is put into a paper "thimble" which is then placed into the main chamber of the Soxhlet extractor. The solvent is heated to reflux and then travels up the distillation arm and floods into the main chamber with the thimble. The chamber then slowly fills and some of the pure compound will dissolve into the solvent. The chamber is emptied with the help of the side arm and the cycle repeats. See also http://chemistry.hull.ac.uk/labweb/glossary_soxhlet.php#

stir-bar sorptive extraction
a new solventless sample preparation method for the extraction and enrichment of organic compounds from aqueous matrices. The method called also as Twister technique is based on the same principles as solid-phase microextraction (SPME). Compared with SPME, a relatively large amount of extracting phase (SPME 0.5 microliters; Twister 50 microliters) is coated on a stir bar. Solutes are extracted into the coating poly(dimethyl siloxane, PDMS) of a stir-bar, based upon their octanol-water partitioning coefficient. In contrast to SPME, in which desorption is performed in the inlet of a gas chromatograph, stir-bar sorptive extraction is used in combination with a thermal-desorption system. After desorption the stir-bar can be used again. The technique has been applied successfully to trace analysis in environmental, biomedical and food applications, e.g. for determination of trace hydrocarbons, PAHs, PCBs in water. Users can obtain extremely low detection limits with good reproducibility. (Source: F. David, B. Tienpont and P. Sandra: Stir-Bar Sorptive Extraction of Trace Organic Compounds from Aqueous Matrices, LCGC Europe, 2003, 1-7)
supercritical fluid extraction
an extraction method (SCFE) where the extraction fluid, usually CO2 is present at a pressure and temperature above its critical point.
unprotected groundwater extraction plant
water extraction well