Search results for "Extraction"
showing 10 items of 2072 documents
Development of a Multifunctional Bioerodible Nanocomposite Containing Metronidazole and Curcumin to Apply on L-PRF Clot to Promote Tissue Regeneratio…
2020
Teeth extractions are often followed by alveolar bone reabsorption, although an adequate level of bone is required for reliable rehabilitations by dental implants. Leukocyte and platelet-rich fibrin (L-PRF) has been widely applied in regenerative procedures and with antibiotic and antioxidant agents could play an essential role in hard and soft tissue healing. In this work, a nanocomposite (Sponge-C-MTR) consisting of a hyaluronate-based sponge loaded with metronidazole (MTR) and nanostructured lipid carriers containing curcumin (CUR-NLC) was designed to be wrapped in the L-PRF&trade
Enhancing extraction performance of organophosphorus flame retardants in water samples using titanium hierarchical porous silica materials as sorbent…
2021
Abstract A sorbent for the extraction of organophosphorus flame retardants has been proposed, based on UVM-7 (University of Valencia Materials) mesoporous silica doped with titanium. Designed cartridges have been applied to the extraction and preconcentration of flame retardants in water samples, followed by gas chromatography coupled to a mass spectrometry detector. Firstly, UVM-7 materials with different contents of titanium were synthesized and characterized by several techniques, thus confirming the proper mesoporous architecture. The potential of these materials was assessed in comparison with their morphological properties, resulting Ti50-UVM-7 the best solid phase. Several extraction…
Over-evaluation of total flavonoids in grape skin extracts containing sulphur dioxide
2015
Abstract Sulphur dioxide (SO 2 ) proved to increase absorbance at 280 nm of grape skin and seed extracts containing it, diluted with ethanol–HCl to assess total flavonoids and anthocyanins in the same analysis. Additional absorbance at 280 nm was also observed in acetone:H 2 O extracts, if the acetone had not completely evaporated before the extracts were diluted with a solvent. Flavonoids were correctly quantified in the extracts when SO 2 or acetone were removed by solid-phase extraction with a C 18 RP as sorbent and methanol as eluting solvent.
Dispersive solid-phase extraction based on oleic acid-coated magnetic nanoparticles followed by gas chromatography-mass spectrometry for UV-filter de…
2011
Abstract A sensitive analytical method to concentrate and determine extensively used UV filters in cosmetic products at (ultra)trace levels in water samples is presented. The method is based on a sample treatment using dispersive solid-phase extraction (dSPE) with laboratory-made chemisorbed oleic acid-coated cobalt ferrite (CoFe 2 O 4 @oleic acid) magnetic nanoparticles (MNPs) as optimized sorbent for the target analytes. The variables involved in dSPE were studied and optimized in terms of sensitivity, and the optimum conditions were: mass of sorbent, 100 mg; donor phase volume, 75 mL; pH, 3; and sodium chloride concentration, 30% (w/v). After dSPE, the MNPs were eluted twice with 1.5 mL …
Isolation of human milk whey proteins by solid phase extraction with a polymeric material modified with gold nanoparticles
2017
Abstract This work describes a method for the isolation of human milk whey proteins by solid-phase extraction (SPE) with a polymeric material modified with gold nanoparticles. Human serum albumin, α-lactalbumin, lactoferrin and lysozyme were selected as target proteins to establish the performance of SPE support. Several experimental variables (pH and ionic strength) that affect the SPE protocol were investigated to achieve the maximum extraction efficiency. Under optimal conditions, the SPE sorbent gave excellent recoveries, and offered a high permeability and reusability (> 20 times). The feasibility of this methodology was successfully demonstrated by isolating the target proteins in a m…
Poly(ethylene glycol) diacrylate-based solid-phase extraction for determination of sulfonamides in meat samples
2020
Abstract In this work, a sorbent based on poly(ethylene glycol) diacrylate (PEGDA) polymer has been synthesized for solid-phase extraction (SPE) of sulfonamides (sulfaguanidine, sulfadiazine, sulfathiazole, sulfapyridine, sulfamethazine, sulfamonomethoxine, sulfamethoxazole, sulfisoxazole) from different meat matrices, which were subsequently determined by HPLC-DAD. Several extraction parameters such as loading and elution solvents as well as other variables (loading capacity, breakthrough volume and reusability) influencing on the analytical performance of the sorbent were optimized. Under the optimal conditions, the developed method was successfully applied to determine the eight sulfonam…
Retention of carbaryl by polyether type polyurethane foam: a critical study
2000
This paper reports the retention of carbaryl by polyether type polyurethane foam in a dynamic mode. Several parameters that can influence the extraction of carbaryl from water samples were investigated such as concentration of carbaryl, mass of sorbent in the column, sample pH, saline concentration, solvent washing and sample flow rate. Results show that it is possible to achieve quantitative extractions when the sample flow rate is maintained up to 2.4 mL min−1, a mass of foam of 300 mg and a sample volume of 30 mL in 0.5 NaCl are employed. They also indicate that there is an ether-like solvent extraction mechanism controlling the sorption of the substance by the foam. Some recovery tests …
Methylone determination in oral fluid using microextraction by packed sorbent coupled to ion mobility spectrometry
2020
Abstract A methodology based on microextraction by packed sorbent (MEPS) followed by ion mobility spectrometry (IMS) has been developed for the simple and automated determination of methylone in oral fluids. MEPS was carried out using a 100 µL eVol® XR hand-held automated analytical syringe filled with octadecyl silica sorbent. The effect of main experimental parameters of MEPS such as sample pH and ionic strength, number of aspirating/dispensing cycles, and elution solvent was studied to obtain a quantitative extraction of methylone. Oral fluid samples were spiked with methylone at different concentration levels from 50 to 400 µg L−1 and analyzed by the proposed MEPS-IMS procedure, giving …
Application of matrix solid-phase dispersion to the determination of a new generation of fungicides in fruits and vegetables.
2002
A method based on matrix solid-phase dispersion (MSPD) and gas chromatography to determine eight fungicides in fruits and vegetables is described. Fungicide residues were identified and quantified using nitrogen-phosphorus detection and electron-capture detection connected in parallel and confirmed by mass spectrometric detection. The method required 0.5 g of sample, C18 bonded silica as dispersant sorbent, silica as clean-up sorbent and ethyl acetate as eluting solvent. Recoveries from spiked orange, apple, tomato, artichoke, carrot and courgette samples ranged from 62 to 102% and relative standard deviations were less than 15% in the concentration range 0.05-10 mg kg(-1). Detection and qu…
Current trends in solid-phase-based extraction techniques for the determination of pesticides in food and environment
2006
Solid-phase extraction (SPE) procedures for pesticide residues in food and environment are reviewed and discussed. The use of these procedures, which include several approaches such as: matrix solid-phase dispersion (MSPD), solid-phase micro-extraction (SPME) and stir-bar sorptive extraction (SBSE), represents an opportunity to reduce analysis time, solvent consumption, and overall cost. SPE techniques differ from solvent extraction depending on the interactions between a sorbent and the pesticide. This interaction may be specific for a particular pesticide, as in the interaction with an immunosorbent, or non-specific, as in the way a number of different pesticides are adsorbed on apolar or…