Search results for "CHEMICAL FRACTIONATION"
showing 10 items of 54 documents
Aqueous enzymatic process assisted by microwave extraction of oil from yellow horn (Xanthoceras sorbifolia Bunge.) seed kernels and its quality evalu…
2013
Abstract In this study, aqueous enzymatic process (AEP) assisted by microwave extraction (ME) of oil from yellow horn ( Xanthoceras sorbifolia Bunge.) seed kernel was investigated. Central composite design (CCD) and response surface methodology (RSM) were used to optimise an enzyme cocktail (cellulase, hemicellulase, pectinase) for AEP. The main factors of ME were also studied. A maximal oil extraction yield of 55.8% was achieved under optimal conditions. Moreover, scanning electron microscope (SEM) was applied to characterise the extraction process. Analysing chemical composition of the extracted oil by GC–MS showed that the content of unsaturated fatty acids by this emerging method (91.18…
Amphetamine-type stimulants analysis in oral fluid based on molecularly imprinting extraction
2018
Abstract A methamphetamine-based molecularly imprinted polymer (MIP) has been prepared by bulk polymerization to recognize new psychoactive substances (NPS) of the amphetamine, cathinones and 2C families in oral fluid samples, being the first precedent of a synthetized MIP for the extraction and preconcentration 32 NPS including amphetamine type substances and synthetic cathinones from oral fluids. Pre-polymerization complex and resulting materials were appropriately characterized by infrared spectroscopy, scanning electron microscopy, and nitrogen adsorption-desorption isotherms. Appropriateness of the material for the specific recognition of the target analytes was also evaluated through …
Swimming pool water--fractionation and genotoxicological characterization of organic constituents.
2005
Swimming pool water treatment in general includes flocculation, sand filtration, and subsequent disinfection with chlorine. The continuous chlorination and input of organic material by bathers in combination with recirculation of the pool water leads to an accumulation of disinfection by-products (DBPs) in the water. Several DBPs have been identified as human carcinogens and are thought to cause allergic asthma. Therefore, the elimination of DBPs is one major aim of pool water treatment. Using membrane filtration as an alternative treatment technology, DBPs can be removed more efficiently than with conventional treatment. In this study membrane filtration and genotoxicity testing were appli…
Influence of15N enrichment on the net isotopic fractionation factor during the reduction of nitrate to nitrous oxide in soil
2007
5 pages; International audience; Nitrous oxide, a greenhouse gas, is mainly emitted from soils during the denitrification process. Nitrogen stable-isotope investigations can help to characterise the N(2)O source and N(2)O production mechanisms. The stable-isotope approach is increasingly used with (15)N natural abundance or relatively low (15)N enrichment levels and requires a good knowledge of the isotopic fractionation effect inherent to this biological mechanism. This paper reports the measurement of the net and instantaneous isotopic fractionation factor (alpha(s/p) (i)) during the denitrification of NO(3) (-) to N(2)O over a range of (15)N substrate enrichments (0.37 to 1.00 atom% (15)…
Maturation of a Key Resource – The Germanium-68/Gallium-68 Generator: Development and New Insights
2011
(68)Ge/(68)Ga radionuclide generators have been investigated for almost fifty years, since the cyclotron-independent availability of positron emitting (68)Ga via the (68)Ge/(68)Ga system had always attracted researches working in basic nuclear chemistry as well as radiopharmaceutical chemistry. However, it took decades and generations of research (and researchers) to finally reach a level of (68)Ge/(68)Ga radionuclide generator designs adequate to the modern requirements of radiometal labelling chemistry. Nevertheless, most of the existing commercial generator systems address aspects of (68)Ge breakthrough and safe synthesis of (68)Ga radiopharmaceuticals by adopting eluate post-processing …
Kaempferol as a dietary anti-inflammatory agent: current therapeutic standing
2020
Inflammation is a physiological response to different pathological, cellular or vascular damages due to physical, chemical or mechanical trauma. It is characterized by pain, redness, heat and swelling. Current natural drugs are carefully chosen as a novel therapeutic strategy for the management of inflammatory diseases. Different phytochemical constituents are present in natural products. These phytochemicals have high efficacy both in vivo and in vitro. Among them, flavonoids occur in many foods, vegetables and herbal medicines and are considered as the most active constituent, having the ability to attenuate inflammation. Kaempferol is a polyphenol that is richly found in fruits, vegetabl…
Sample preparation methods for the determination of pesticides in foods using CE-UV/MS.
2010
Much progress has been made in pesticide analysis over the past decade, during this time hyphenated techniques involving highly efficient separation with sensitive detection have become the techniques of choice. Among these, methods based on separation with mass spectrometric detection have resulted in greater likelihood of identification and are acknowledged to be extremely useful and authoritative methods for the determination of pesticide residues but the inherent advantages of the use of CE as a separation technique are well-known and can be summarized as high separation efficiency, low analysis time, high resolution power, and low consumption of samples and reagents. Although UV is the…
Analytical comparison and sensory representativity of SAFE, SPME, and Purge and Trap extracts of volatile compounds from pea flour
2012
Pisum sativum is of great economic and nutritional interest due to its protein content. Nevertheless, pea products are underused as a protein source in human food because of their strong beany flavour. Therefore, the objective of this study was to select an efficient and representative method to extract volatile molecules of pea flour. In the first step, three extraction methods were chosen: solid phase micro extraction (SPME); Purge and Trap extraction and solvent assisted flavour evaporation (SAFE). The corresponding extracts were analysed by gas chromatography coupled with mass spectrometry. In the second step, the sensory representativity of the extracts was assessed either by direct ga…
Determination at low ppm levels of dithiocarbamate residues in foodstuff by vapour phase-liquid phase microextraction-infrared spectroscopy
2010
Abstract A methodology based on the vapour phase (VP) generation of carbon disulphide from non-volatile dithiocarbamate compounds has been developed for determination of pesticide residues in foodstuff at low ppm levels. The method involves a selective reaction combined with liquid phase microextraction (LPME) and transmission infrared measurements. The use of a home made transmission cell improved the detection limits (LOD) compared to the use of attenuated total reflectance measurements by a factor of approximately 80. Using the most appropriate experimental conditions for the CS2 generation and LPME preconcentration, the precision of the methodology, expressed as the relative standard de…
Tuning the surface of nanoparticles: Impact of poly(2-ethyl-2-oxazoline) on protein adsorption in serum and cellular uptake
2016
Item does not contain fulltext Due to the adsorption of biomolecules, the control of the biodistribution of nanoparticles is still one of the major challenges of nanomedicine. Poly(2-ethyl-2-oxazoline) (PEtOx) for surface modification of nanoparticles is applied and both protein adsorption and cellular uptake of PEtOxylated nanoparticles versus nanoparticles coated with poly(ethylene glycol) (PEG) and non-coated positively and negatively charged nanoparticles are compared. Therefore, fluorescent poly(organosiloxane) nanoparticles of 15 nm radius are synthesized, which are used as a scaffold for surface modification in a grafting onto approach. With multi-angle dynamic light scattering, asym…