Sonication-assisted extraction

Aparicio I, Santos JL, Alonso E (2007) Simultaneous sonication-assisted extraction, and determination by gas chromatography-mass spectrometry, of di-(2-ethylhexyl)phthalate, nonylphenol, nonylphenol ethoxylates and polychlorinated biphenyls in sludge from waste-water treatment plants. Anal Chim Acta 584 455 161... 

Sanchez-Brunete C, Miguel E, Tadeo J. Rapid method for the determination of polycyclic aromatic hydrocarbons in agricultural soils by sonication-assisted extraction in small columns. J. Sep. Sci. 2006 29 2166-2172. 

Kjartannson, G.T., S. Zivanovic, K. Kristbergsson and J. Weiss, Sonication-Assisted Extraction of Chitin from Shells of Fresh Water Prawns, Journal of Agriculture and Food Chemistry, 54, 3317-3323 (2006). 

This overview is focused on the on-line coupling of pressurized liquid extraction (PLE), microwave-assisted extraction (MAE), supercritical fluid extraction (SEE) and sonication-assisted extraction (SAE) with liquid and gas chromatography for the analysis of solid agricultural and food samples. In addition, head-space techniques and direct thermal extraction are discussed. 

In the sample preparation of semi- and nonvolatile compounds, solvent extraction is typically used for extracting the analytes of interest from a sample matrix. For volatile analytes, head-space or thermal extraction are good alternatives to solvent-based techniques. Several novel extraction systems that utilize elevated temperatures of pressures in the extraction have been developed particularly for solvent-based extraction methods. These new methods typically are much faster and often more selective than older methods and consume smaller amounts of organic solvents and reagents. Commercially available systems with the ability to heat and pressurize liquids include pressurized liquid extraction (PLE), microwave-assisted extinction (MAE) and supercritical fluid extraction (SFE). Also sonication-assisted extraction (SAE) has given promising results. 

In sonication assisted extraction (SAE), acoustic vibrations with frequencies above 20 kHz are applied to the sample. The vibrations cause cavitation in the liquid that is, bubbles with a negative pressure are formed. When the cavitation bubbles collapse, shock waves are generated, which enhance the removal of analytes from the matrix surface. Moreover, implosion of cavities creates microenvironments of high temperatures and pressures. Traditionally, SAE is performed in static mode. In on-line combinations, the extraction is dynamic 27,28). 

Sanchez-Brunete, C., Rodriguez, A., and Tadeo, J. L., Multiresidue analysis of carbamate pesticides in soil by sonication assisted extraction in small columns and liquid chromatography, J. Chromatogr. A, 1007, 85-91, 2003. 

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. 

Several options are available for the analysis of flame retardants in environmental samples. Good results can be obtained with most of the methods, as has been shown in several interlaboratory studies.For example, in an interlaboratory study of PBDEs in sediments and biological samples, various methods were used both for sample pretreatment and final analysis. In the extraction, Soxhlet, PLE, sonication assisted extraction, and SFE were used, utilizing different solvents. The cleanup procedures varied largely as well. In the final analysis, GC-MS with either HRMS or LRMS was used, with varying column dimensions and stationary phases. The results agreed well with all the methods used, although some problems were noticed in the analysis of BDE-209. ... 

Although conventional extraction methods, such as Soxhlet, do provide accurate results, it can be assumed that the faster and less laborious extraction techniques such as PLE, sonication assisted extraction, and SFE will gain popularity. The relevant figures of merit of the techniques utilized in the extraction of FRs in environmental samples are summarized in Table 31.9. Gas chromatography is the obvious choice for the final separation of the analytes. Selective and sensitive detection, i.e., MS or ECD, is required, as the levels of the FRs tend to be very low and other compounds are typically present in much higher concentrations. 

Kjartansson GT, Zivanovic S, Kristbergsson K et al (2006) Sonication-assisted extraction of chitin from shells of fresh water prawns (Macrobrachium rosenbergii). J Agr Food Chem 54 3317-3323... 

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). 

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