Search results for "Salting out"
showing 6 items of 6 documents
Comprehensive analysis of airborne pesticides using hard cap espresso extraction-liquid chromatography-high-resolution mass spectrometry
2017
A hard cap espresso extraction procedure has been developed to recover airborne pesticides in particulate matter trapped in filters. This extraction step was made for 20s at 72°C and 19bar using 50mL of 20% (v/v) acetonitrile in water. After that, based on NaCl salting out, extracts were concentrated 22 times and analysed by ultra-high performance liquid chromatography - high resolution mass spectrometry. 35 pesticides were evaluated, as a proof of concept, being validated the whole methodology and compared the extraction method with that based on microwave assisted extraction for 20min. In short, the method avoids cross-contamination of samples, it is relatively fast and consumes only 10mL…
Ionic Liquid Based Headspace Solid-Phase Microextraction-Gas Chromatography for the Determination of Volatile Polar Organic Compounds
2010
Solid-phase microextraction (SPME) with an ionic liquid (IL) coating was developed for headspace extraction of a group of low molecular weight alcohols (ethanol, n-propanol, butanol, and isopropyl alcohol), acetone, ethyl acetate, and acetonitrile. A first SPME fiber was simply coated with a dedicated IL whose synthesis is described. A second SPME fiber was prepared by gluing silica (Si) particles on which the synthesized IL was chemically bonded. The analytes SPME extraction was optimized for time, temperature, and NaCl salting out content. The headspace extracted analytes were determined by simple temperature desorption into the hot injection port of a gas chromatograph. The coated-IL fib…
Interfacial water structure controls protein conformation.
2007
A phenomenological theory of salt-induced Hofmeister phenomena is presented, based on a relation between protein solubility in salt solutions and protein-water interfacial tension. As a generalization of previous treatments, it implies that both kosmotropic salting out and chaotropic salting in are manifested via salt-induced changes of the hydrophobic/hydrophilic properties of protein-water interfaces. The theory is applied to describe the salt-dependent free energy profiles of proteins as a function of their water-exposed surface area. On this basis, three classes of protein conformations have been distinguished, and their existence experimentally demonstrated using the examples of bacter…
Understanding fat, proteins and saliva impact on aroma release from flavoured ice-creams
2017
Publication également référencée sous le numéro WOS:000437803400018; The release profile of fourteen aroma compounds was studied in ice cream samples varying in fat and protein, both in level and type. In vitro aroma release was monitored by solid phase micro-extraction gas chromatography using an innovative saliva reactor, which imitated human chewing under temperature control. The results showed that the effect of the fat type on aroma release was smaller than that of fat level. Ice creams with low fat level released more hydrophobic aroma compounds than ice creams with high fat level. At low fat level more aroma compounds were released from ice creams with lower protein content. At high …
Retention of aroma compounds: an interlaboratory study on the effect of the composition of food matrices on thermodynamic parameters in comparison wi…
2010
BACKGROUND: Partition coefficients give an indication of the retention of aroma compounds by the food matrix. Data in the literature are obtained by various methods, under various conditions and expressed in various units, and it is thus difficult to compare the results. The aim of the present study was first to obtain gas/water and gas/matrix partition coefficients of selected aroma compounds, at different temperatures, in order to calculate thermodynamic parameters and second to compare the retention of these aroma compounds in different food matrices. RESULTS: Yogurts containing lipids and proteins induced a higher retention of aroma compounds than model gel matrices. The observed effect…
An integrated approach for the HCl and metals recovery from waste pickling solutions: pilot plant and design operations
2021
Abstract Continuous regeneration of industrial pickling solutions and recovery of valuable materials are implemented in a pilot-scale plant including diffusion dialysis (DD), where HCl is recovered, membrane distillation (MD), where HCl is concentrated, and reactive precipitation (CSTR), where metal ions are recovered in different forms. The integration of the three processes allows to minimize waste streams generation and to accomplish a closed-loop process, thus increasing the environmental sustainability and economic impact of the galvanizing industry. Process reliability was proved through the operation of a demonstrator in the real industrial environment of the Tecnozinco SrL hot-dip g…