Search results for "Saponification"
showing 9 items of 29 documents
An efficient acetylation of dextran using in situ activated acetic anhydride with iodine
2010
A facile, efficient, cost-effective and solvent-free acetylation method has been developed for the acetylation of dextran. Dextran acetates were successfully synthesized using different molar ratios of acetic anhydride in the presence of iodine as a catalyst without the use of any solvent. The reactions were realized at 50?C for 3 h under stirring and nitrogen. This efficient method yielded highly pure and organosoluble dextran esters. The reaction appears highly effective for obtaining higher degrees of substitution (DS) with great efficiency. Under solvent-free conditions, dextran triacetates were efficiently synthesized. It was also observed that the molar ratio can easily control the DS…
Darstellung, eigenschaften und umsetzungen von polyvinylsulfofluoriden
1960
Vinylsulfofluorid wurde mit Azo-bis-isobutyronitril polymerisiert. Es wurden Polymerisationsgrade bis 390 erreicht. Die Molekulargewichte wurden durch Viskositatsmessungen an den durch Verseifung der Polyvinylsulfofluoride gewonnenen Natriumsalzen der Polyvinylsulfonsaure ermittelt. Die Polyvinylsulfofluoride wurden mit Ammoniak, aliphatischen und aromatischen Aminen umgesetzt. Dabei wurden Umsatze bis zu 80 Mol% erreicht. Vinylsulfofluoride was polymerized with azo-bis-isobutyronitrile. The degree of polymerisation was up to 390. The molecular-weights were determined by measuring the viscosity of the sodium-salts of polyvinylsulfonic acids obtained by saponification of polyvinylsulfofluori…
Analysis of Contaminants in Beverages
2019
Abstract The main purpose of our researches, in the last years, was to develop reliable methods for the determination of emerging and old contaminants (Pt, Rh, V, Mo, polycyclic aromatic hydrocarbons (PAHs), etc.), at trace levels, in the solutions obtained from the mineralization or extraction of environmental and food matrices, because, in particular for metals, some of them cannot be readily analyzed using traditional method, for example, inductively coupled plasma-optical emission spectrometry and inductively coupled plasma with mass spectrometry techniques. Few data are available on the evaluations of Pt, Rh, V, and Mo concentrations, in food matrices, because have ever been carried ou…
Effect of a physical pre-treatment and drying on carotenoids of goji berries ( Lycium barbarum L.)
2018
In order to evaluate the influence of an abrasive pre-treatment and drying at 50 °C, 60 °C, 70 °C of goji fruits (Lycium barbarum L.), changes in colour and carotenoids were studied. An extraction method was modified and adapted to assay the main carotenoid esters and saponified carotenoids of goji berries, before and after treatments. Goji berries were confirmed as a high source of zeaxanthin, with zeaxanthin-dipalmitate at about 2 g/kg dry weight. The reliability of the analytical method was confirmed by the high quantitative recoveries, about 100%, a higher repeatability than reference methods and a good reproducibility (lower than 5%). After drying, significant but small carotenoid loss…
Sterol oxidation in ready-to-eat infant foods during storage.
2008
The effect of storage on sterol oxidation of ready-to-eat infant foods was evaluated. Two different flavor (honey -LH- or fruits-LF-) liquid infant foods, prepared with milk and cereals, were stored for 0, 2, 4, 7 and 9 months, at 25ºC. Sterol oxidation products (SOP) were extracted by cold saponification, purified by silica solid-phase and analyzed by gas chromatography (GC) and GC-mass spectrometry. -sitosterol was the most representative sterol, followed by cholesterol and campesterol. No significant differences in the total and single SOP content (0.8-1 mg/kg of product) were observed with respect to storage time and type of sample; the main SOP found was 7-ketositosterol (< …
Determination of sterols, oxysterols, and fatty acids of phospholipids in cells and lipoproteins: A one-sample method
1998
In addition to fatty acids, especially polyunsaturated species, cholesterol oxidizes and leads to various oxygenated derivatives, named oxysterols. They display a wide range of adverse biological properties. Monitoring oxysterols is important in the evaluation of the potential risks associated with lipid oxidation. In the present study, a quick and reliable method was developed for analysis of oxysterols, sterols, and fatty acid composition of phospholipids in the same biological sample. Total lipid extraction was determined after addition of several internal standards (epicoprostanol for sterols, 19-hydroxy-cholesterol for oxysterol and di-heptadecanoyl-phosphatidylcholine for phospholipid…
Patterning of a Surface Immobilized ATRP Initiator with an Inkjet Printer
2010
A new technique for patterning polymer brushes on the micrometer scale has been developed in which an inkjet printer was used to deposit droplets of acid on a surface-immobilized initiator for atom transfer radical polymerization (ATRP). The acid cleaved an ester bond in the ATRP initiator in a saponification reaction. As a result, the ATRP initiator was rendered inactive. To control the degree of defunctionalization, a new initiator containing a weak ester bond was derived from a tertiary alcohol. Comparison to an established ATRP initiator, derived from a primary alcohol, showed that the novel initiator was defunctionalized with a higher efficiency. Control of the reaction time allowed to…
ChemInform Abstract: Convenient High Yielding Gram Scale Solution Synthesis of Methionine-Enkephalin.
2010
A simple, large-scale synthesis of a cytokine, methionine-enkephalin, Tyr-Gly-Gly-Phe-Met, has been elaborated. Classical solution peptide chemistry methods without protection of amino acid side-chain functions and 1+(2+2) segment condensation were used. A nine-step synthesis from commercial amino acid derivatives was developed with yields ranging from 86% to 99%, averaging 92%. The purity of all intermediates was found to be 99.0-100% by HPLC. The process has been used to prepare greater than 150 g quantities of the pentapeptide as a monohydrate of 100% purity. Hydantoin formation was observed during saponification of Boc-Tyr-Gly-Gly-Phe-Met-OMe and minimised.
Convenient High Yielding Gram Scale Solution Synthesis of Methionine-Enkephalin.
1998
A simple, large-scale synthesis of a cytokine, methionine-enkephalin, Tyr-Gly-Gly-Phe-Met, has been elaborated. Classical solution peptide chemistry methods without protection of amino acid side-chain functions and 1+(2+2) segment condensation were used. A nine-step synthesis from commercial amino acid derivatives was developed with yields ranging from 86% to 99%, averaging 92%. The purity of all intermediates was found to be 99.0-100% by HPLC. The process has been used to prepare greater than 150 g quantities of the pentapeptide as a monohydrate of 100% purity. Hydantoin formation was observed during saponification of Boc-Tyr-Gly-Gly-Phe-Met-OMe and minimised.