Ultrasonic liquid-solid extraction

Ultrasonic extraction is a well-known commercial method to increase mass transfer rate by cavitation forces. Bubbles in the liquid-solid extraction using UE can explosively collapse and produce localized pressure, improving the interaction between the intracellular substances and the solvent to facilitate the extraction of the phytochemical. 

PLE pressurized liquid extraction, SPE solid phase extraction, UE ultrasonic extraction, DSPE dispersive solid phase extraction, SBSE stir bar sorptive extraction, TD-GC-MS thermal desorption-gas chromatography-mass spectrometry, LAS linear alkylbenzene sulfonates, CDEAs coconut diethanol amides, NPEOs nonylphenol ethoxylates, DP degradation products, SPC sulphenyl carboxylates, PCDD dibenzo-p-dioxins (PCDD), PCDF dibenzofurans, PCBs biphenyls... 

Sonication helps improve solid-liquid extractions. Usually a finely ground sample is covered with solvent and placed in an ultrasonic bath. The ultrasonic action facilitates dissolution, and the heating aids the extraction. There are many EPA methods for solids such as soils and sludges that use sonication for extraction. The type of solvent used is determined by the nature of the analytes. This technique is still in widespread use because of its simplicity and good extraction efficiency. For example, in research to determine the amount of pesticide in air after application to rice paddy systems, air samples collected on PUF were extracted by sonication, using acetone as the solvent. The extraction recoveries were between 92% and 103% [21]. 

Lipids from liquid samples or cell suspensions may be extracted directly into organic solvents but solid samples will require prior treatment, such as homogenization or ultrasonication. The solvents are chosen with reference to the nature of the lipids present and to some extent, the type of sample, e.g. animal or vegetable tissue. Ethanol-diethyl ether (3 1) with subsequent extraction... 

The variations concern pH, temperature, time of processing, and, in the last case additionally, possible ultrasonic treatment. The following step consists in a liquid-phase or solid-phase extraction (SPE). However, other extraction methods like SFE ° also have been used prior to the detection procedure. The final choice of the workup procedure is mainly dependent on the chemical stability of the analyte e.g., benzodiazepines are highly unstable under alkaline conditions, but they are also affected under acid conditions. Alkaline hydrolysis should be avoided for cocaine - however, morphine can be extracted after acid or alkaline hydrolysis. ... 

Spray desolvation involves spraying a polymer solution onto a desolvating liquid. For example, microparticles can be made by spraying a PVA solution onto an acetone bath. Here, the polymer solvent (water) is extracted into acetone, and PVA precipitates to form solid micro-particles.f In another example, bovine serum albumin (BSA) was encapsulated in poly(lactic-co-glycolic acid) (PLGA) by this method. The micronized drug was suspended in a PLGA-acetone solution and atomized ultrasonically into ethanol bath. ° ... 

Other manual methods include a solid-liquid extraction, which consists of placing the solvent in a tube with sample and shaking the sample and filtering. This method is also called the shake-filter method. The solvent may be heated to improve extraction efficiency. Several other simple methods include sonica-tion of the sample with an ultrasonic probe and heated solvent, and dissolution of the sample directly with solvent (Majors, 1996). 

Extraction Shaking, ultrasonication, Soxhlet, liquid-liquid partitioning, solid-phase extraction To extract analytes from sample matrix into solution... 

Sun, F., Littlejohn, D., and Gibson, M. D., Ultrasonication extraction and solid phase extraction clean-up for determination of U.S. EPA 16 priority pollutant polycyclic aromatic hydrocarbons in solids by reversed-phase liquid chromatography with ultraviolet detection. Anal. Chim. Acta, 364, 1-11, 1998. 

There are several solvents that are used for the extraction of PCBs from sediment and soil. The most common are -hexane, ° dichloromethane, " cyclohexane, and mixtures of them. Ultrasonic treatment can improve the interaction between the solid and the liquid phase. 

Ultrasonic LSE is most applicable to the isolation of semivolatile and nonvolatile organic compounds from solid matrices such as soil, sediment, clays, sand, coal tar, and other related solid wastes. U-LSE is also very useful for the disruption of biological material such as serum or tissue. U-LSE can be coupled with solid-phase extraction (SPE) to give a very robust sample preparation method at relatively low cost in comparison to MAE and ASE approaches. The author has utilized U-LSE/SPE to isolate and recover 9,10-dimethyl-l,2-benzanthracene from animal bedding. A 89% recovery was obtained for bedding that was spiked with this polycyclic aromatic hydrocarbon (PAH) of interest to toxicologists (20). An ultrasonic horn and tip are immersed into a mixture of liquid extractant and solid sample and sonicated at some percent of full power for a finite length of time, either continuously or pulsed. 

A, acaricide AV, avicide I, insecticide F, fungicide H, herbicide GR, growth regulator N, nematocide R, rodenticide US, ultrasonication LLE, liquid-liquid extraction CU, cleanup ImCU, immuno cleanup SPE, solid-phase extraction MSPD, matrix solid-phase dispersion SBSE, stir bar sorptive extraction SD, steam distillation FMSE, focused microwave Soxhiet extraction PFE, pressurized fluid extraction ASE, assisted solvent extraction ScFE, subcritical fluid extraction SFE, supercritical fluid extraction SEC, size-exclusion chromatography LC, liquid chromatography (fraction collection) LTLP, low temperature lipid precipitation. 

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