Soxhlet solvent extraction

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. 

Extraction of residues from soil samples is much more difficult than their extraction from plant or water samples. The pesticide residues in the soil exist often in several forms as bound residue , which may affect the extraction efficiency of pesticides from the soil. Then, various extraction methods such as organic solvent extraction, Soxhlet extraction, sonication extraction, microwave dissolution and supercritical fluid extraction (SEE) are used. Some extraction methods are described in the following. 

The composition and yield of curcuminoids extracted using the existing techniques, e.g. hydrodistillation, low-pressure solvent extraction, soxhlet and SC-C02 extraction, were compared (Braga et al., 2003). The highest yield was obtained using soxhlet extraction with ethanol and the lowest (2.1%) with hydrodistillation. The best solvent for SC-C02 extraction is a mixture of ethanol and isopropanol. ar-Curcumene, z-(y)-atlantone and ( )-(y)-atlantone constituted about 60% of the light fraction. 

Several standard methods for the quantitative analysis of food samples are based on measuring the sample s mass following a selective solvent extraction. For example, the crude fat content in chocolate can be determined by extracting with ether for 16 h in a Soxhlet extractor. After the extraction is complete, the ether is allowed to evaporate, and the residue is weighed after drying at 100 °C. This analysis has also been accomplished indirectly by weighing a sample before and after extracting with supercritical GO2. 

For extraction of solid materials with a solvent, a Soxhlet extractor is commonly used. This technique is applied, for example, in the alcohol extraction of dyes to free them from insoluble contaminants such as sodium chloride or sodium sulfate. 

Cobalt (II) meso-5.10,15,20-tetraphenylporphine complex [14172-90-8] M 671.7. Brown crystals from Et20 or CHCl3-MeOH (cf iron chloride complex). Recrystd by extraction (Soxhlet) with CgHg. Sol in most organic solvents except MeOH and pet ether. [UV, IR J Am Chem Soc 70 1808 7948 81 5111 7959.]... 

Braga et al. ° compared the efficiencies of several processes, i.e., hydrodistillation, low pressnre solvent extraction, and Soxhlet and supercritical fluid extraction. For each process, the inflnences of several parameters (duration, temperature, nature of solvent) were also evalnated. These authors concluded that the Soxhlet method performed with ethanol/isopropanol 1/100 v/v for 2 hr and 30 min was the most effective. Snn et al. nsed solid phase extraction to concentrate (nine times) a... 

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. 

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. 

Solvent degassing (LC) 553 Solvent demixing (TLC) 660 Solvent effects, splitless injection (GC) 250 Solvent extraction 753 applications 766 hoBogenizer 761 i plitgers 756 micTMethods 764 microwave 761 optimization 753 shake flask 761 solvent reduction 763 Soxhlet 762 Solvent (LC)... 

Figure 8.6 Apparatus used for saeple preparation involving solvent extraction. A, heavier-than-water continuous liquid-liquid extractor B, pressurized Soxhlet extractor for use with supercritical fluids C, Kudema-Danlsh evaporative concentrator 0, autonated evaporative concentrator.

The classical methods of solvent extraction of polymers can be conveniently divided into those for which heat is required (Soxhlet/Soxtec ), and those methods for which no heat is added, but which utilise some form of agitation, i.e. shaking or sonication (Table 3.3). Other LSE procedures consist in soaking the polymer in boiling solvents [84,85] and cold LSE [80,86]. These methods are also time-consuming, use large amounts of solvents which are scheduled to be restricted in the future, and exhibit other limitations when analytes are present in small quantities, where they may actually be lost in concentration steps following extraction. Many norms are still based on such standard procedures [87,88],... 

An important QC analysis in the fibre and textile industry is the surface finish determination by Soxhlet extraction (AATCC Test Method 94-1992). Solvent extraction is used on textile materials to determine naturally occurring oily and waxy materials that have not been completely removed from the fibres (ASTM Method D 2257-96). Meanwhile, environmental, safety... 

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. 

David and Seilier [1] compared the efficiencies of various extraction techniques including supercritical fluid [2], high pressure solvent and Soxhlet extraction for the removal of organophosphorus hydraulic fluids from soil. High pressure solvent extraction was at temperatures up to 200°C and pressures up to 170 bar was the favoured technique. Extraction efficiencies were similar in all three methods, but the favoured method was more rapid and cheaper to operate. 

Nowicki et al. [51] point out that in the development of a Soxhlet sample preparation technique for sediment samples, the empty paper Soxhlet thimbles contained organic contaminants which adversely affected results. Glass thimbles were tried and found to be satisfactory. The authors detail the identification of organics solvent-extracted from paper and glass Soxhlet thimbles, and discuss the stability for multiple use of the two materials for trace organic sample preparation. 

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