Accelerated solvent extraction systems

Dionex Corporation - Manufacturers of liquid chromatography systems (IC and HPLC), chromatography software data systems, reversed-phase and ion-exchange columns, and accelerated solvent extraction systems... http //www.dionex.com. 

FIGURE 6 Schematic representation of an accelerated solvent-extraction system, showing pneumatic and fluidic pathways. 

An Accelerated Solvent Extraction system (ASE 200 from Dionex Corp. Sunnyvale, CA, USA) equipped with a solvent controller unit was used to perform all the extractions. 

Ghana. H.. Kikuchi, K.. Okihashi, M, and Hori, S. (1997), Deierminaiion of organophosphorus pesticides in foods using a accelerated. solvent extraction system, Anafy.vf 122, 217-220. 

Richter, B. E., J. L. Ezzell, D. Felix, K. A. Roberts, and D. W. Later. 1995. An Accelerated Solvent Extraction System for the Rapid Preparation of Environmental Organic Compotmds in Soil, American Laboratory, vol. 7, pp. 24-28. 

Accelerated solvent extraction (ASE), capillary chromatography sample preparation, 4 609, 610 Accelerated temperature, humidity, and bias (THB) tests, 10 9 Accelerated weathering tests, 19 584 Acceleration, exponents of dimensions in absolute, gravitational, and engineering systems, <5 584t Accelerators, 9 554-555 10 411, 713 22 61 23 861-862 for cement, 5 485... 

Some of the newer procedures use the same basic principles as the older extraction methods but provide fast and easy-to-use options and generally consume less organic solvent. For the most part, they have higher initial purchase price than the traditional methods. Examples include supercritical fluid extraction, accelerated solvent extraction, and automated solid-phase extraction and microextraction. Modular systems are now readily available that automate these proce-... 

Wennrich et al. [167] investigated the capabilities of coupling accelerated solvent extraction with water as the extraction solvent and solid-phase microextraction to determine chlorophenols in polluted soils. Subcritical water extraction was performed using a commercially available accelerated solvent extractor. This system solves the problem of the analytes partitioning back to the soil matrix, which can occur in straightforward subcritical water extraction because in the Wennrich et al. method [167] the aqueous phase and the soil are separated under the extraction conditions. 

Phase separation in all solvent extraction systems, including CSSX, is greatly enhanced by the application of relatively high centrifugal forces that are generated in the separating zone of centrifugal solvent extraction contactors. Typical acceleration fields... 

The ground plant samples are weighed (typically 7 to 20 g, depending on plant part) and extracted in a semi-automated process utilizing a Dionex ASE300 accelerated solvent extractor system. The samples are placed in stainless steel cells and sealed. Approximately 33 to 66 mL of 95% EtOH are added and the cells are placed under 1500 PSI, preheated for 5 min to 40°C and held at this temperature... 

The accelerated solvent extraction (ASE) system introduced by Dionex uses standard solvents at elevated temperatures and pressures to increase extraction efficiency. Samples are placed in stainless-steel extraction vessels that are loaded into the ASE that has been programmed for the extraction protocol. The instrument allows for the unattended extraction of 24 samples. The initial units allowed for solvent blending by premixing solvents before they were placed into the ASE. Recent modifications allow solvent blending to be accomplished in-line. There has been some controversy about the use of the name ASE because it points to instrumentation from one company and other companies have introduced competing products. It has been proposed that the ASE technology be more correctly referred to as pressurized fluid extraction because ASE denotes a commercial device. 

Since pressurized fluid extraction (PFE), also known as accelerated solvent extraction (ASE ), is a relatively new technique, the commercial availability of PFE instruments is limited. A commercial PFE system ( ASE 200 ) currently available is a fully automated sequential extractor developed by the Dionex Corporation, USA. This mainly consists of a solvent-supply system, extraction cell, oven, collection system and purge system, all of which are under computer control. A schematic diagram of a PFE system is shown in Figure 7.15. This system (ASE 200) can operate with up to 24 sample-containing extraction vessels and up to 26 collection vials, plus an additional four vial positions for rinse/waste collection. 

Accelerated solvent extraction is a closed system of extraction which utilises higher temperature and pressure. Closed systems are designed to minimise the loss of volatiles, improve the efficiency and increase the throughput. The elevated temperature improves analyte solubility. For example, anthracene, a PAH, is 15 times more soluble in methylene chloride at 150°C than at 50°C. High temperature also helps to overcome sample extraction matrix effects and gives faster desorption kinetics. The lower solvent viscosity allows diffusion of the solvent into the matrix to occur more quickly than other extraction techniques. Increased pressure also elevates the boiling point of the solvent. 

OTHER COMMENTS used in organic synthesis for introducing the methylamino group intermediate for accelerators, dyes, pharmaceuticals, insecticides, and fungicides useful as a fuel additive, polymerization inhibitor, component of paint removers, photographic developer, rocket propellant, and solvent possible uses in solvent extraction systems. 

The classical approach to extract PAHs from lipophilic compounds which are abundant in marine matrices is by means of saponification in basic (NaOH or KOH) alcoholic solution [indicatively see (Webster et al. 2006 Rank 2(X)9)] or the Soxhlet extraction with organic solvents mainly acetone, n-hexane and DCM [indicatively see (Vorkamp et al. 2010 Yoshimine et al. 2012)]. Both methods are widespread, but time consuming. For this reason more fast methods which reduce time, labour and solvent use were pursued by researchers. These include Sonication Assisted Extraction (Maioli et al. 2010 Dsikowitzky et al. 2011), Microwave Assisted Liquid Extraction (MAE) (Cortazar et al. 2008 Zuloaga et al. 2009), and Accelerated Solvent Extraction or Pressurized Liquid Extraction (ASE) usually conducted with the Dionex system (Sloan et al. 2004). Finally the matrix solid-phase dispersion (MSPD) has also been applied to extract PAHs from mussels even in miniaturized scale (Campins-Falco et al. 2008). 

Table 2.3 as a completely worked out example using quantitative solvent extraction, ash content determination, TGA, FTIR, XRF, GC-MS, HS-GC-MS, PyFTIR, ICP, and s-NMR. Information on the cure and antidegradant systems was obtained (assigned species/possible origin), as follows cyclohexane thiol/CBS accelerator benzothiazole/MBT, MBTS or CBS accelerators N, A-dimethylformamide/TMTD accelerator phthalim-ide/Santoguard PVI and IV-phenylbenzene amine/possi-bly a diphenyl/acetone amine antioxidant. 

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