Sonication extraction

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. 

On a laboratory scale, generally an ultrasonic probe (horn) and an ultrasonic cleaner are used. The ultrasonic field in an ultrasonic cleaner is not homogeneous. Sonication extraction uses ultrasonic frequencies to disrupt or detach the target analyte from the matrix. Horn type sonic probes operate at pulsed powers of 400-600 W in the sample solvent container. Ultrasonic extraction works by agitating the solution and producing cavitation in the... 

Brandt [200] has extracted tri(nonylphenyl) phosphite (TNPP) from a styrene-butadiene polymer using iso-octane. Brown [211] has reported US extraction of acrylic acid monomer from polyacrylates. Ultrasonication was also shown to be a fast and efficient extraction method for organophosphate ester flame retardants and plasticisers [212]. Greenpeace [213] has recently reported the concentration of phthalate esters in 72 toys (mostly made in China) using shaking and sonication extraction methods. Extraction and analytical procedures were carefully quality controlled. QC procedures and acceptance criteria were based on USEPA method 606 for the analysis of phthalates in water samples [214]. Extraction efficiency was tested by spiking blank matrix and by standard addition to phthalate-containing samples. For removal of fatty acids from the surface of EVA pellets a lmin ultrasonic bath treatment in isopropanol is sufficient [215]. It has been noticed that the experimental ultrasonic extraction conditions are often ill defined and do not allow independent verification. 

It is not uncommon that extraction techniques are unfairly compared. Appropriate interlaboratory studies are few. Soxhlet and sonication extraction (EPA methods 3540 and 3550, respectively) were compared in an interlaboratory study (129 participants) for PCBs in soil. Results from laboratories using Soxhlet extraction were significantly more accurate than those obtained using sonication, especially at higher concentrations, but with equal precision [196]. This is rationalised by the observation that the Soxhlet procedure presents the sample with fresh solvent so that the extraction solvent is never saturated, unlike the sonication procedure. Sonication is very sensitive to the solvent polarity, nonpolar solvents producing considerably less accurate results than polar solvents. It is not as sensitive to clean-up procedures as... 

Dunnivant, F.M. and A.W. Elzerman. 1988. Determination of polychlorinated biphenyls in sediments, using sonication extraction and capillary column gas chromatography-electron capture detection with internal standard calibration. Jour. Assoc. Offic. Anal. Chem. 71 551-556. 

Sonication extraction with 1 1 dichloromethane/acetone. Dried extracts with sodium sulfate, concentrated. Solvent exchanged to MTBE. 

One of the new techniques that has emerged in recent years is sonication extraction. A short overview of the application of this method to alkylphenols and APEO has been given recently by Petrovic et al. [3]. The reduction in extraction time and solvent use for sonication compared with Soxhlet extraction are substantial, and recoveries are comparable or better. 

Sedi ment Sonication extraction GC/ECD and No data 98.6 (solvent Onuska et... 

Soil, sludge, or solid waste Extracted by soxhlet or sonication, extract subjected to column chromatographic cleanup and concentrated GC-MS (EPA Method 8250A) 1.5 mg/kg (0.43c+1.26)/c x 100 where c is the actual concentration EPA 1994a... 

Soxhlet extraction (EPA SW-846 3540) is a very efficient extraction process that is commonly used for semivolatile petroleum constituents. In the method, the solvent is heated and refluxed (recirculated) through the soil sample continuously for 16 hours, or overnight. This method generates a relatively large volume of extract that needs to be concentrated. Thus, it is more appropriate for semivolatile constituents than for volatile constituents. Sonication extraction (EPA SW-846 3550) can also be used for semivolatile compounds, and as the name suggests, involves the use of sound waves to enhance analyte transfer from sample to solvent. Sonication is a faster technique than Soxhlet extraction and can require less solvent. 

Oostdyk TS, Grob RL, Snyder JL, et al. 1995. Supercritical fluid extraction of primary aromatic amines from characterized soil samples comparison with sonication extraction. J Environ Sci Health A30(4) 783-816. 

Initial Discoveries. Xylose isomerase activity was initially found in 1953 in extracts of Lactobacillus pentosus (14), followed by similar activities in extracts of Pseudomonas hydrophila and Pasteurella pestis in the mid-1950s (15-17). An enzyme activity that was found to convert glucose to fructose was discovered in 1957 (18). This activity, found in sonicated extracts from Pseudomonas hydrophila, was enhanced in the presence of... 

Polyalcohols Sonication, extraction with HjO, (chicory, toffees)/ Carbopac PA 100-quaternary amine NaOH solution PAD [75] ... 

Probe sonication extraction with (CH3)2C0 centrifugation filtration... 

A comparison of extraction methods for primary aromatic amines including 1,4-phenylenediamine, 2,4-diaminotoluene, benzidine, 4,4 -methylenebis (2-chloroanilme), 3,3 -dimethylbenzidine, and 3,3 -dichlorobenzidine from solid matrices was conducted. Supercritical fluid extraction (SEE) was evaluated and compared with the classical method, sonication extraction (Oost-dyk et al., 1993). 

EPA. 1986 Method 3550. Sonication extraction. In Test methods for evaluating solid waste. Vol IB, Laboratory manual, Physical/chemical methods. SW846. U.S. Environmental Protection Agency, Office of Solid Waste and Emergency Response, Washington DC, 3rd ed. 

Dunnivant, F. M. M.S. Thesis ( Determination of Polychlorinated Biphenyl Concentrations in Selected Sediments Using a Sonication Extraction Technique ), Clemson University, Clemson, SC, 1985. 

To check recovery of compound from the medium, he ran a labeling study. Radiolabeled sample was added to runoff water at 5 ppt, it was sonicated, extracted with a wetted SPE, eluted as before, and counted. He found a 97% recovery of radiolabel from the SFE. 

Soils, sediments, and solid samples mixed with anhydrous Na2S04 and then methylene chloride sonicated extract cleaned by acid-base partitioning and analyzed as above. 

Solid matrices mixed with anhydrous Na C/, followed by methylene chloride sonicated extract cleaned by acid-based partitioning and analyzed by GC-NPD, GC-F1D, or GC/MS. 

Extraction of solid samples Homogenization extractions Sonication extractions Microwave assisted extractions Soxhlet extractions Accelerated solvent extractions Supercritical fluid extractions Extraction of liquid samples Liquid-liquid extractions Solid phase extractions (SPE)... 

The Chromatium transhydrogenase was isolated by Keister and Hemmes 16) from a sonicated extract of Chromatium strain D. After high-speed centrifugation and ammonium sulfate precipitation, two subsequent steps of DEAE-cellulose chromatography were employed. The purity of the preparation was tested for various reductase.and dehydrogenase activities. 

Supercritical fluid extraction is a modern sample preparation technique of great interest and utility for complex matrices, primarily considered as an alternative for Soxhlet and sonication extraction for solid and semisolid matrices. 

Sonication extraction with 2-butoxyethanol (recovery for spiking experiments 40-122%) followed by ion-exchange HPLC-ICP-MS or HG-ICP-MS... 

Ultrasound extraction (sonication) is based on the conversion of AC current at 50/60 Hz into electrical energy at 20 kHz and its transformation in mechanical vibrations. Due to the cavity, microscopical vapor bubbles are formed and, after implosion, they produce strong shockwaves into the sample. For isolating the (semi)volatile organic compounds, the liquid-liquid ultrasound technique is applied to samples such as soils, sediments, coal, etc. The process is also useful for the biological materials destruction (Loconto, 2001). Sonication extraction is faster than Soxhlet extraction (30-60 min per sample) and allows extraction of a large amount of sample with a relatively low cost, but it still uses about as much solvent as Soxhlet extraction, is labor intensive, and filtration is required after extraction. 

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