نتایج جستجو برای: sfe
تعداد نتایج: 815 فیلتر نتایج به سال:
Recent genetic studies attribute the negative correlation between population genetic diversity and distance from Africa to a serial founder effects (SFE) evolutionary process. A recent linguistic study concluded that a similar decay in phoneme inventories in human languages was also the product of the SFE process. However, the SFE process makes additional predictions for patterns of neutral gen...
Various beneficial properties has been attributed to Nigella sativa, including its antioxidant potential. Previously, it was reported that supercritical fluid extraction (SFE) could be used to obtain N. sativa extract rich in antioxidants. In the present study, N. sativa extracts prepared using the previously optimized SFE as well as the traditional Soxhlet extraction approaches were analyzed f...
With the aid of gas chromatography-mass spectrometry (GC-MS), a systematical and analytical evaluation method called Taguchi’s quality engineering has been applied to the in-situ supercritical fluid extraction (SFE) and chemical derivatization (ChD) of amphetamines from water to afford the optimal experimental conditions and hence achieved the highest recoveries of the analytes (as their triflu...
In this study, the effect of tensile test temperature (148 to 673 K) on the microstructural evolutions and the mechanical properties of high manganese twinning induced plasticity (TWIP) steel with the chemical composition of Fe- 31Mn-3Al-3Si (wt. %) was investigated. XRD, SEM and TEM were used to study the microstructural evolutions. Stacking fault energy (SFE) of the alloy was also calculated ...
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...
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