Accelerated-solvent extraction

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. 

As with ASE, microwave power can be used to extract contaminants from soil samples. The microwaves rapidly heat the solvents producing greater efficiencies in analyte recoveries and reduced extraction times. The solvents used need to 

SFE has a wide range of applications, which include the extraction of PAHs, PCBs, phenols, pesticides, herbicides, and hydrocarbons from environmental samples, contaminants from foods and feeds, and active gradients from cosmetics and pharmaceutical products. Table 3.6 lists some examples from the literature. 

Accelerated solvent extraction (ASE) is also known as pressurized fluid extraction (PFE) or pressurized liquid extraction (PLE). It uses conventional solvents at elevated temperatures (100 to 180°C) and pressures (1500 to 2000 psi) to enhance the extraction of organic analytes from solids. ASE was introduced by Dionex Corp. (Sunnyvale, CA) in 1995. It evolved as a consequence of many years of research on SFE [45], SFE is matrix dependent and often requires the addition of organic modifiers. ASE was developed to overcome these limitations. It was expected that conventional solvents would be less efficient than supercritical fluids, which have higher diffusion coefficients and lower viscosity. However, the results turned out to be quite the opposite. In many cases, extraction was faster and more complete with organic solvents at elevated temperature and pressure than with SFE. Extensive research has been done on the extraction of a variety of samples with ASE. ASE was approved by EPA as a standard method in 1996. 

The elevated pressure and temperature used in ASE affects the solvent, the sample, and their interactions. The solvent boiling point is increased under high pressure, so the extraction can be conducted at higher temperatures. The high pressure also allows the solvent to penetrate deeper into the sample matrix, thus facilitating the extraction of analytes trapped in matrix pores. At elevated temperatures, analyte solubility increases and the mass transfer is faster. The high temperature also weakens the solute matrix bond due to 

Polycyclic aromatic hydrocarbons (PAHs) Standard reference materials (SRMs) 5 

Carbamate pesticides (carbaryl, aldicarb, Filter paper and silica 32 

---

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. 

Shen, J. and Shao, X., Comparison of accelerated solvent extraction, Soxhlet extraction, and ultrasonic-assisted extraction for analysis of terpenoids and sterols in tobacco. Ana/. Bioanal. Chem., 383, 1003, 2005. 

Bergeron, C. et al.. Comparison of the chemical composition of extracts from Scutellaria lateriflora using accelerated solvent extraction and supercritical fluid extraction versus standard hot water or 70% ethanol extraction, J. Agric. Food Chem., 53, 3076, 2005. 

On the other hand, quantitative extraction requires complete and exhaustive extraction and no material can be lost. To assure complete extraction when a food is analyzed for the first time in a laboratory, it is useful to carry out two or three extractions, pool the solvents, and keep separate the next extracts to verify the presence of carotenoids. Usually four to six extractions are enough to remove the carotenoids completely from a sample. The extraction can be carried out in a blender, vortex, or with a mortar and pestle. Accelerated solvent extraction (ASE), an important extraction technique in residue analysis, currently attracts interest due to its short duration, low level of solvent use, and high extraction yield. The average recoveries for all carotenoids with the exception of norbixin ranged from 88.7 to 103.3% using manual extraction and from 91.0 to 99.6% by ASE (70 bar and temperature of 40°C) both extractions were carried out with a mixture of MeOH, EtOAc, and petroleum ether (1 1 1). ... 

Breithanpt, D.E., Simultaneons HPLC determination of carotenoids nsed as food coloring additives applicability of accelerated solvent extraction. Food Chem., 86, 449, 2004. 

In the past decade, new sample extraction techniques have been introduced to meet stricter criteria in the areas of food and agriculture, for example, enviromnentally friendly, non-toxic, fast, automated, robust, and cost-efficient techniques. Accelerated solvent extraction (ASE) and pressurized liquid extraction (PEE) are two methods developed for the extraction of chemicals of interest " and provide high yields and efficiency from a wide range of botanical, - animal, and biological samples. ASE and PLE combine solvents at elevated temperatures (40 to 200°C)... 

Kuriki, K., Tajima, K., and Tokudome, S., Accelerated solvent extraction for quantitative measurement of fatty acids in plasma and erythrocytes. Lipids, 41, 605, 2006. 

Obana, H., Eurata, M., and Tanaka, Y., Analysis of 2-aUcylcyclobutanones with accelerated solvent extraction to detect irradiated meat and fish, J. Agric. Food Chem., 53, 6603, 2005. 

Richter, B.E. et al.. Accelerated solvent extraction a technique for sample preparation. Anal. Chem., 68, 1033, 1996. 

The first step for the determination of PAHs is removal from the matrix by solvent extraction, which preferably is performed with boiling toluene or benzene (hot solvent extraction by refluxing see Jacob and Grimmer 1994), although other solvents (e.g. tol-uene/acetone, acetone, and dichloromethane) and other extraction procedures (ultrasonic treatment, Soxhlet extraction, and accelerated solvent extraction) can also be applied. 

Accelerated solvent extraction (ASE) is a technique which attempts to merge the beneficial solvation properties of SFE with traditional organic solvents. Specifically, the sample is placed in an extraction vessel which can withstand high pressures while being maintained at a constant temperature. Extraction is carried out by pumping the extraction solvent through the samples for a limited time. As an example of the use of ASE, Richter and Covino extracted PCBs from a 10-g fish tissue sample with hexane... 

The need to understand the fate of pesticides in the environment has necessitated the development of analytical methods for the determination of residues in environmental media. Adoption of methods utilizing instrumentation such as gas chro-matography/mass spectrometry (GC/MS), liquid chromatography/mass spectrometry (LC/MS), liquid chromatography/tandem mass spectrometry (LC/MS/MS), or enzyme-linked immunosorbent assay (ELISA) has allowed the detection of minute amounts of pesticides and their degradation products in environmental samples. Sample preparation techniques such as solid-phase extraction (SPE), accelerated solvent extraction (ASE), or solid-phase microextraction (SPME) have also been important in the development of more reliable and sensitive analytical methods. 

Soxhlet extraction Ultrasonic disruption Supercritical fluid extraction Accelerated solvent extraction... 

MAE simply involves placing the sample with the solvent in specialized containers and heating the solvent using microwave energy. MAE is also sometimes called MASE, which can stand for microwave-assisted solvent extraction or microwave-accelerated solvent extraction. In any event, the extraction process is more rapid than Soxhlet extractions, can be run in batches, and reduces solvent consumption. As in the case of sonication, MAE may overcome retention of the analyte by the matrix, but analyte degradation can be a problem at higher temperatures in certain applications. 

B. Richter, J. EzzeU, and D. Felix, Single Laboratory Method Validation Report Extraction of Organo-phosphorus Agrochemicals, Chlorinated Herbicides and Polychlorinated Biphenyls Using Accelerated Solvent Extraction (ASE) with Analytical Validation by GC/NPD and GC/ECD, Document 101124, Dionex Sunnyvale, CA (1994). 

Table 3.4 summarises the main characteristics of a variety of sample preparation modes for in-polymer additive analysis. Table 3.5 is a short literature evaluation of various extraction techniques. Majors [91] has recently reviewed the changing role of extraction in preparation of solid samples. Vandenburg and Clifford [4] and others [6,91-95] have reviewed several sample preparation techniques, including polymer dissolution, LSE and SEE, microwave dissolution, ultra-sonication and accelerated solvent extraction. 

Figure 3.19 Accelerated solvent extraction of Irganox 1010 from PP with 2-propanol at various temperatures. Points, experimental data solid lines, curve fitted using the hot-ball model. After Vandenburg et al. [37], Reprinted with permission from HJ. Vandenburg et al., Analytical Chemistry, 70, 1943-1948 (1998). Copyright (1998) American Chemical Society...

The main drawback of this technique is solvent and time-consuming. In the last decade, there have been efforts to develop extraction techniques that allow efficient extraction and reduced solvent volumes in shorter times, incorporating high levels of automation, such as pressurized liquid extraction (PLE) [commonly known as accelerated solvent extraction (ASE)]. 

Ding Y, Zhang W, Gu C, Xagoraraki I, Li H (2011) Determination of pharmaceuticals in biosolids using accelerated solvent extraction and liquid chromatography/tandem mass spectrometry. J Chromatogr A 1218 10-16... 

Difrancesco etal. [18] 22 FMs including PCMs and NMs Digested sewage sludge U.S. - Accelerated solvent extraction with dichloromethane - Silica gel chromatography - GC-MS... 

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... 

Zuloaga O, Etxebarria N, Fernandez LA, Madariaga J. Comparison of accelerated solvent extraction with microwave-assisted extraction and Soxhlet for the extraction of chlorinated biphenyls in soil samples. Trends Anal. Chem. 1998 17 642-647. 

---