Search results for "Solvent extraction"
showing 10 items of 37 documents
Pressurized liquid extraction of organic contaminants in environmental and food samples
2015
Pressurized liquid extraction (PLE) is an automated technique that uses elevated temperature and pressure to achieve exhaustive extraction from solid matrices, so reducing solvent consumption and enhancing sample throughput when compared with traditional procedures. Hence, it can be considered an environment-friendly technique, generating small volumes of waste and reducing costs and time. This review focuses on application of this green technique to the analysis of organic contaminants in food and environmental matrices for monitoring purposes. We examine fundamentals and key aspects of the development of a PLE method, including pressurized hot-water extraction, together with some relevant…
Studies of short-lived fission products by means of the multistage solvent extraction system SISAK
1990
The multistage solvent extraction system SISAK is described. The system is used for online studies of nuclides with half-lives down to ∼1 s. Some of the chemical separation procedures are presented, and a survey is given on the results obtained so far. The possiblity to gain access to nuclides with even shorter half-lives is also discussed.
Silymarin compounds: Chemistry, innovative extraction techniques and synthesis
2020
Abstract Silymarin complex consisting of four flavonolignans (silychristin, silydianin, silibinin and taxifolin) has been used from ancient times in both traditional European and Asian medicine for liver disorders treatment. Moreover, over the last years, the anticancer activity of these compounds against various types of cancer cells (e.g., breast, skin, colon, cervix, ovary, prostate, lung and hepatocellular cancers, among others) has been demonstrated. Therefore, at this stage of development, food and pharmaceutical interest have shown an increased interested in the recovery of these molecules. Conventional solvent extraction has been traditionally used to recover silymarin complex from …
Separation and identification of petroporphyrins extracted from the oil shales of Tarfaya: geochemical study
2002
Abstract Vanadyl and nickel porphyrins were isolated from the oil shales of Tarfaya (Morocco) by extraction followed by column chromatography. The ratios and characteristics of these porphyrin complexes were essentially obtained on the basis of UV–visible and mass spectrometry data. Geochemical information could be drawn from these data. The nature and the contents of the metals coordinated and non-coordinated to porphyrin systems were also determined in this study.
Efficiency of QuEChERS approach for determining 52 pesticide residues in honey and honey bees
2016
A comparison between QuEChERS and other pesticide extraction procedures for honey and honey bee matrices is discussed. Honey bee matrix was extracted by solvent based procedure whereas solid phase extraction was the protocol for the honey matrix. The citrate buffered QuEChERS method was used for both matrices. The methods were evaluated regarding cost (equipment and reagents), time, accuracy, precision, sensitivity and versatility. The results proved that the QuEChERS protocol was the most efficient method for the extraction of the selected pesticides in both matrices. QuEChERS is the most economical and less time-consuming procedure.SPE and solvent-based extraction procedures show equivale…
An ultrasonic-assisted process for copper recovery in a des solvent: Leaching and re-deposition
2017
Abstract The continuous growth of the electronic equipment market has led to an increased amount of scraping that it becomes necessary to recover. A hydrometallurgical method for copper and precious metal recovery from e-waste must consist of a number of steps: leaching, ion separation and subsequent electrochemical re-deposition of the target metal. Although this task is achievable in aqueous solutions, it requires strong acid or cyanide solutions. The aim of the study is to develop a new environmentally benign process by using a Deep Eutectic Solvent (DES), a form of cheap and safe ionic liquid, as an electrolyte for both leaching and electrodeposition. The experiments were conducted in a…
An improved system for fast, continuous chemical separations (“SISAK 2”) in nuclear spectroscopic studies
1980
Abstract An improved rapid, continuous solvent extraction system (“SISAK 2”) is described. The system is connected to a gas-jet installed at the Mainz reactor. It allows single or multistage chemical separations of liquid phases by means of specially designed centrifuges within ∼1 s per stage. The application of this system to study short-lived nuclides is exemplified for neutron-rich lanthanum and cerium isotopes produced by fission.
Rapid Radiochemical Separation Procedures from Aqueous Solutions
1992
The state-of-the-art in the field of rapid radiochemical separation procedures is illustrated by two systems using aqueous solutions as input: ARCA, an apparatus for repetitive separations, and SISAK, a centrifuge system for continuous separations. Applications presented are: Solvent extraction of element 105 investigated with 34-s 262105 using ARCA, and decay scheme studies of the fission product 1.0-s 110Tc by means of SISAK.
Accelerated solvent extraction of ochratoxin a from rice samples.
2005
In this paper, accelerated solvent extraction (ASE) for the analysis of ochratoxin A (OTA) is applied for the first time. Optimization of the method is given for the extraction of OTA from rice samples. Several parameters such as type of solvent, temperature, pressure, static time, and cell size were investigated thoroughly to find the optimal extraction conditions. The optimum ASE operating conditions were methanol as extraction solvent, 1500 psi, 40 degrees C, 5 min of static time, 50% flush volume, 60 s of purge, 1 cycle, and 11 mL cell size. The total extraction time was approximately 15 min. OTA was determined by liquid chromatography coupled with a fluorescence detector and confirmed …
Ochratoxin A in rice on the Moroccan retail market
2008
One hundred (100) samples of rice purchased from retail markets in five different cities (Rabat, Témara, Salé, Casablanca and Méknès) in Morocco from January to October 2006 were surveyed for the presence of ochratoxin A (OTA) using Accelerated Solvent Extraction (ASE) coupled to liquid chromatography with fluorescence detection. The identification of OTA in positive rice samples was confirmed by methyl ester derivatization. Analytical results showed a frequency of contamination of 26% of total analyzed rice samples. The percentage of contamination of samples was 24, 26.6, 16.6, 27.7 and 30% in Rabat, Témara, Méknès, Salé and Casablanca respectively. Levels of OTA in positive samples ranged…