نتایج جستجو برای: مدل تعادل تابع عرضه sfe
تعداد نتایج: 148514 فیلتر نتایج به سال:
The water resources of the western United States depend heavily on snowpack to store part of the wintertime precipitation into the drier summer months. A well-documented shift toward earlier runoff in recent decades has been attributed to 1) more precipitation falling as rain instead of snow and 2) earlier snowmelt. The present study addresses the former, documenting a regional trend toward sma...
Background: Orange peel essential oils were obtained using supercritical fluid extraction. This method is an important high scaling extraction methods that used for extraction of plant and animal extracts. Methodology: The experimental parameters of SFE such as temperature, pressure, and extraction time and modifier volume were optimized using a central composite design after a 24-1fractional ...
Calophyllum brasiliense is a rich source of bioactive coumarins, xanthones and biflavonoids. The aim of the study was to compare the phenol contents and the antioxidant activity of C. brasiliense extracts obtained by conventional and supercritical fluid extraction (SFE) methods, as well as the quantification of crude extracts and (-)-mammea A/BB yields. Dichloromethane and hexane were used as s...
In the present work supercritical fluid extraction (SFE) using CO2, was applied for the pre-treatment of mandarin peels. Two-step extraction, combining SFE and conventional extraction, was investigated. During the first extraction step supercritical CO2 at temperatures 25, 40 and 60°C and pressures from 100 to 300 bar was applied to remove the non-polar components from the extracting material. ...
A multiresidue analysis of pesticides in tea using supercritical fluid extraction (SFE) and GC-MS was developed. The preprocessing using SFE shortened the total analysis time. The SFE extract contained less matrices than the extract obtained with organic solvents. However, these matrices disturbed instrumental analysis. So, the extract was cleaned up with ENVI™-Carb/NH2 and InertSep™ SI cartrid...
The development of automatized hyphenated systems is attractive to avoid sampling error, save time and reduce costs. Among these systems, on-line SFE-SFC allows the extraction, separation, detection molecules in an efficient, quick eco-friendly way. After a historical introduction explanation on use supercritical fluids for extraction or analysis, principles fluid (SFE) chromatography (SFC) wil...
This work was aimed to extract and characterise the essential oils presented in the leaves of Moringa Oleifera using supercritical fluid extraction (SFE) and compare the results against those using the conventional Soxhlet extraction method. The oils extracted were analysed using GC-MS. The compounds were identified according to their retention indices and mass spectra (EI, 70eV). The effects o...
Alpinia officinarum has been confirmed to possess bioactivities against some pests. In this work, a sample was obtained from A. officinarum rhizomes by supercritical fluid CO₂ extraction (SFE). According to GC-MS analysis, the main chemical components for SFE-sample included benzylacetone (26.77%), 1,7-diphenyl-5-hydroxy-3-heptanone (17.78%), guaiacylacetone (10.03%) and benzenepropanal (7.42%)...
The application of supercritical fluid extraction to cocaine and its metabolites in blood and urine.
Supercritical fluid extraction (SFE) is emerging as a valuable analytical technique for use as an alternative to conventional solid-phase (SPE) and liquid-liquid extraction techniques. It is a relatively new technique based on the use of supercritical fluids for the isolation of analytes from various matrices and is attracting great interest because of the increasing need for a simple, rapid, e...
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