Liquid-solid extraction sonication

Liquid-liquid extraction or liquid-solid extraction for aqueous samples (and soxhlett extraction or sonication for nonaqueous samples), followed by sample concentration, cleanup, and determination by GC or GC/MS. Direct injection, waste dilution, or other extraction techniques, depending on the sample matrices, may be used. 

Another extraction method that has been used in soil analysis (Fish and Revesz, 1996) and works for food analysis is microwave solvent extraction. It consists of placing a sample in an open or closed container capable of high pressure and heated by microwave energy, causing extraction of the analyte (Fish and Revesz, 1996). This method is yet another form of solvent extraction and differs in how the sample is heated. Its advantages lie in the fact that it can replace traditional solvent extraction and sonication with a fast and safe method of liquid-solid extraction. 

A typical sample preparation method for a solid dose is to add the sample or a triturated dose to a suitable solvent. Dissolution of the compounds of interest can be accelerated by stirring, shaking, or sonication. These methods allow the precise control of volume and temperature. Soxhlet extractors (see Section V.A) are designed for liquid-solid extraction, but are rarely used. 

The most common extraction techniques for semivolatile and nonvolatile compounds from solid samples that can be coupled on-line with chromatography are liquid-solid extractions enhanced by microwaves, ultrasound sonication or with elevated temperature and pressures, and extraction with supercritical fluid. Elevated temperatures and the associated high mass-transfer rates are often essential when the goal is quantitative and reproducible extraction. In the case of volatile compounds, the sample pretreatment is typically easier, and solvent-free extraction methods, such as head-space extraction and thermal desorption/extraction cmi be applied. In on-line systems, the extraction can be performed in either static or dynamic mode, as long as the extraction system allows the on-line transfer of the extract to the chromatographic system. Most applications utilize dynamic extraction. However, dynamic extraction is advantageous in many respects, since the analytes are removed as soon as they are transferred from the sample to the extractant (solvent, fluid or gas) and the sample is continuously exposed to fresh solvent favouring further transfer of analytes from the sample matrix to the solvent. 

Techniques. LLE, liquid-liquid extraction LSE, liquid-solid extraction MAE, microwave assisted extraction PLE, pressurized liquid extraction SAE, sonication assisted extraction SEE, supercritical fluid extraction SPE, solid phase extraction TBA, tetrabutylanunonium hydroxide. 

A-EtFOSE, A-EtFOSAA, FOSAA, FOSA, N-EtFOSA, PFOSI (perfluorooctane sulfinate), PFOA, PFOS Solid-liquid extraction — Sonication and centrifugation — Extract poured into a new tube + MeOH — Purification by dispersed solvent (ENVI-Carb) — (in parallel) SPE from headspace sampling LC-ESI-MS-MS (QqQ) 0.1 pg/L (vial)a 46-49 pmol (microcosm)3 [85]... 

Extraction of solid samples Homogenization extractions Sonication extractions Microwave assisted extractions Soxhlet extractions Accelerated solvent extractions Supercritical fluid extractions Extraction of liquid samples Liquid-liquid extractions Solid phase extractions (SPE)... 

Liquid extraction, sonication. NPD Waste water, solid wastes... 

Polynuclear aromatic hydrocarbons (PAHs) 610, 8100 Liquid extraction, sonication, Soxhlet extraction, SPE FID Waste water, solid wastes... 

A second portion of the extract ( 25 mg) was dissolved as completely as possible in 5 ml -hexane using sonication and mechanical agitation. This solution was loaded onto a liquid-solid chromatography column layered from the bottom to top with activated copper (for sulfur removal), deactivated alumina (5% water), and activated silica gel (Grade 62 and 923). The column was eluted with n-hexane followed by 30% DCM in n-hexane. 

Accelerated solvent extraction (ASE), focused microwave soxhiet extraction (FMSE), immuno affinity cleanup (im-Cu), liquid-liquid extraction (LLE), low-temperature lipid precipitation (LTLP), matrix solid-phase dispersion (MSPD), microwave-assisted extraction (MAE), nanofiltration (NF), pressurized fluid extraction (PEE), single drop microextraction (SOME), solid-phase extraction (SPE), solid-phase microextraction (SPME), steam distillation (SD), stir bar sorptive extraction (SBSE), surpercritical fluid extraction (SFE), subcritical fluid extraction (ScFE), supported liquid membrane extraction (SLME), ultra-sonication (US), size exclusion chromatography (SEC), liquid chromatography-fraction collection (LC)... 

Acrylonitrile and 603, 8015, 8031 P T, liquid extraction, sonication FID, NPD Wastewater, solid wastes [20,244]... 

Classical extraction is achieved by mixing the samples with an organic solvent (solid-liquid extraction) such as acetonitrile, methanol, or ethanol, used either in the pure form or as a mixture or aqueous solution." Extraction time can be reduced by sonicating the samples. ... 

Sonication helps improve solid-liquid extractions. Usually a finely ground sample is covered with solvent and placed in an ultrasonic bath. The ultrasonic action facilitates dissolution, and the heating aids the extraction. There are many EPA methods for solids such as soils and sludges that use sonication for extraction. The type of solvent used is determined by the nature of the analytes. This technique is still in widespread use because of its simplicity and good extraction efficiency. For example, in research to determine the amount of pesticide in air after application to rice paddy systems, air samples collected on PUF were extracted by sonication, using acetone as the solvent. The extraction recoveries were between 92% and 103% [21]. 

Waste water, soil, sediment, solid waste Extraction (liquid-liquid, Soxhiet, sonication) with organic solvent such as dichloromethane, removal of water, volume reduction. GC/MS (EPA method 8270) 20 g/L (ppb) for wastewater 1,300 g/kg (ppb) for low soil, sediment 110 at 100 g/L (100 ppb) EPA 1986a... 

Most existing methods are based on instrumental analysis involving exhaustive sample pretreatment and preconcentration steps, followed by purification and fractionation before final chromatographic separation and detection. For fat and oil samples, dissolving the lipids in an appropriate solvent is usually the first treatment. This has been achieved by melting the fat at 90°C followed by LLE or direct solid liquid extraction (SEE) with an apolar solvent [37], column extraction with a mixture of apolar solvents after drying of the sample with anhydrous Na2S04, Soxhlet extraction and/or sonication with apolar solvents. Typically, sample intake is between 0.5 g and 1 g and quantitative recoveries >60% have been reported. 

Vegetable juice add dihydrophylloquinone (internal standard) to sample. Extract with 2-PrOH/hexane (3 + 2) and water aided by sonication and vortexing. Silica solid-phase extraction in the sample cleanup mode. Milk as described for vegetable juice followed by liquid-phase reductive extraction for removal of lipids. 

Aqueous samples are extracted with methylene chloride using a separatory funnel or a continuous liquid-liquid extractor. Solid samples are extracted with methylene chloride-acetone mixture (1 1) by either sonication or Soxhlett extraction. The methylene chloride extract should be finally exchanged to hexane or iso-octane or methyl tert-butyl ether. The latter solvents should be mixed with acetone during solvent exchange. The extracts should then be cleaned up by Florisil. Often Florisil cleanup reduces the percent recovery of analyte to less than 85%. A preliminary screening of the extract should, therefore, be done to determine the presence of interference and the necessity of florisil cleanup. Gel permeation cleanup also lowers the analyte recovery and thus is not recommended. If a FPD is used in the GC analysis, the presence of elemental sulfur can mask the analyte peaks. In such a case, sulfur cleanup should be performed. Sample extraction and cleanup procedures are described in Chapter 1.5. 

Aqueous samples are extracted with methylene chloride by liquid-liquid extraction. The extract is concentrated and then exchanged to hexane. Soils, sediments, and solid wastes are extracted by sonication or Soxhlett extraction. Samples should be spiked with one or more surrogate standard solution to determine the accuracy of analysis. Some of the internal standards mentioned above may also be used as surrogates. If only the PCBs are to be analyzed, hexane instead of methylene chloride may be used throughout. Oil samples may be... 

LLE liquid-liquid extraction, SPE solid phase extraction, LPME liquid-phase microextraction, ESI electrospray ionization, APCI atmospheric pressure chemical ionization, SSI sonic spray ionization, Q quadrupole, QqQ triple quadrupole, TOF time-of-flight, IT ion trap, IS internal standard, CV coefficient of variation, MRE mean relative error, LOD limit of detection, LLOQ lower limit of quantification... 

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