Solvent extraction microwave-assisted

MICROWAVE-ASSISTED SOLVENT EXTRACTION AND A NEW METHOD FOR ISOLATION OF TOTAL PETROLEUM HYDROCARBONS (TPH) FROM PLANTS WITH COLUMN CHROMATOGRAPHY (SILICA GEL AND ALUMINA) AND DETERMINATION WITH SPECTROFLUOROPHOTOMETRY... 

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. 

Microwave-assisted solvent extraction is usually carried out in one of the following modes ... 

Applications The broad industrial analytical applicability of microwave heating was mentioned before (see Section 3.4.4.2). The chemical industry requires extractions of additives (antioxidants, colorants, and slip agents) from plastic resins or vulcanised products. So far there have been relatively few publications on microwave-assisted solvent extraction from polymers (Table 3.5). As may be seen from Tables 3.27 and 3.28, most MAE work has concerned polyolefins. 

MAE has also been used for the extraction of adipate plasticisers from PVC [464]. The efficiency of MAE depends on the kind of solvent, the temperature achieved and the heating time. The final temperature reached depends on the microwave power, number of vessels and irradiation time. Higher recovery values than SEE were reported for both phthalate and adipate. Other reports on microwave-assisted solvent extraction have appeared [465-467]. 

Work is in progress to validate the MAE method, proposed for EPA, in a multi-laboratory evaluation study. Nothing similar has been reported for additives in polymeric matrices. Dean el al. [452] have reviewed microwave-assisted solvent extraction in environmental organic analysis. Chee et al. [468] have reported MAE of phthalate esters (DMP, DEP, DAP, DBP, BBP, DEHP) from marine sediments. The focus to date has centred on extractions from solid samples. However, recent experience suggests that MAE may also be important for extractions from liquids. 

Font N, Hernandez F, Hogendoorn EA, Baumann RA, van Zoonen P. Microwave-assisted solvent extraction and reversed-phase liquid chromatography-UV detection for screening soils for sulfonylurea herbicides. J. Chromatogr. A 1998 798 179-186. 

Pedersen and Lindholst [41] used microwave-assisted solvent extraction followed by SPE to determine octylphenol in liver and muscle of Rainbow trout. 

Flotron, V., J. Houesson, A. Bosio, C. Delteil, A. Bermond, and V. Camel. 2003. Rapid determination of polycyclic aromatic hydrocarbons in sewage sludges using microwave-assisted solvent extraction. Comparison with other extraction methods. J. Chromatogr. A 999 175-184. 

Microwave-assisted solvent extraction is another method that uses intensive wave energy to dispense extraction solution to the inner core... 

Camel, V. Microwave-assisted solvent extraction of environmental samples. Trends Anal. Chem. 19, 229-248 (2000)... 

Alternatively, one could use a Soxhlet or similar apparatus to extract the sample. Other methods to prepare a sample for analysis through extraction include supercritical fluid extraction (SFE), pressurized fluid extraction, and microwave-assisted solvent extraction. 

In microwave-assisted solvent extraction (MASE), the sample and solvent are heated directly rather than in more conventional schemes where the vessel is heated to extract the sample. The sample solvents are placed into a closed vessel that does absorb microwaves. This facilitates the extraction of the samples... 

K. K. Chee, M. K. Wong, H. K. Lee, Optimization of microwave-assisted solvent extraction of polycyclic aromatic hydrocarbons in marine sediments using a microwave extraction system with high-performance liquid chromatography-fluorescence detection and gas chromatography-mass spectrometry. Anal. Chim. Acta. 330 (1996), 217. 

Percent extracted (key equation 18.10), p. 543 Solvent extraction of metal ions-complexes, chelates, p. 544 Accelerated and microwave-assisted solvent extraction, p. 546 Solid-phase extraction, p. 547 Solid-phase microextraction, p. 551... 

Patsias, J., Papadakis, E. N., and Papadopoulou-Mourkidou, E., Analysis of phenoxyalkanoic acid herbicides and their phenolic conversion products in soil by microwave assisted solvent extraction and subsequent analysis of extracts by online SPE-liquid chromatography, J. Chromatogr. A, 959, 153-161, 2002. 

Hogendoom, E. A., Huls, R., Dijkman, E., and Hoogerbmgge, R., Microwave assisted solvent extraction and coupled-column reversed-phase liquid chromatography with UV detection. Use of an anal)4ical restricted-access-medium column for the efficient multi-residue analysis of acidic pesticides in soils, J. Chromatogr. A, 938, 23-33, 2001. 

Chee, K. K., Wong, M. K., and Lee, H. K., Determination of organochlorine pesticides in water by membranous solid-phase extraction, and in sediment by microwave-assisted solvent extraction with gas chromatography and electron capture detector and mass spectrometric detection, J. Chromatogr. A, 736, 211-218, 1996. 

LSE, liquid solid extraction p.b., phosphate buffer MASE, microwave assisted solvent extraction HWE, hot water extraction SPE, solid phase extraction. 

Molins, C., Hogendoom, E. A., Heusinkveld, H. A. G., Van Harten, D. C., Van Zoonen, P., and Baumann, R. A., Microwave assisted solvent extraction (MASE) for the efficient determination of triazines in soil samples with aged residues, Chromatographia, 43, 527-532, 1996. 

Extraction of phthalate esters from sohd samples is mostly performed by Soxhlet extraction or sonication. In addition, microwave assisted solvent extraction, supercritical fluid extraction, and ASE are used to extract phthalate esters from environmental solid matrices (see Table 28.8). 

A microwave-assisted solvent extraction (MASE) method was optimized by Chee et al. to extract phthalate esters from marine sediments, soils, and results were compared with those obtained by the same authors using conventional Soxhlet and sonication techniques. The analysis was performed by GC-ECD or GC-MS. The overall optimal conditions for the extraction of phthalate esters by MASE included the use of 1 1 acetone or hexane at 115°C for 10 min. Recoveries for six individual phthalate esters (DMP, DEP, DAP, DBP, BBP, DEHP) ranged from 71% to 91%, and were better than those obtained with Soxhlet (66% to 90%) or sonication (65% to 89%). The authors stated that advantages of MASE extraction over sonication or Soxhlet are larger sample throughput, lower usage of hazardous solvents, and less laborious cleanup steps. 

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