نتایج جستجو برای: extraction of pahs by sfe

تعداد نتایج: 21627770  

2009
Masturah Markom Wan Ramli Wan Daud Masitah Hasan

Fractionation of plant compounds to produce active purified fractions is a multi-step process, time-consuming and sometimes very expensive. This paper presents a single-step fractionation of tannins from a local plant, Phyllanthus niruri Linn. using supercritical fluid extraction (SFE) method. The effects of operating conditions (pressure, temperature, flow rate, cosolvent content and ethanol-w...

2003

Solid phase extraction (SPE) and supercritical fluid extraction (SFE) have become established in the field of analytical chemistry over the last five years. Both techniques are alternatives to classical analytical extraction methods used to separate analytes from solid and liquid matrices. SFE is an alternative to traditional liquid-solid extraction methods, the two most common being soxhlet an...

2007
Scott L. Taylor

The total oil content of soyflakes, canola seed and wetmilled corn germ were determined by analytical supercritical fluid extraction (SFE) with carbon dioxide as the extraction solvent. Results obtained by SFE were in excellent agreement with those obtained by a conventional Soxhlet technique with organic solvents. The analyticalscale SFE technique yielded average means within one standard devi...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه شهید بهشتی - دانشکده علوم 1372

a simple, sensitive and selective method for solvent extraction and spectrophotemetric determination of lanthanum (ii) europium (iii), and cerium (iii) is described , the rare earth metals are extracted into chloroform solution of n-phenylbenzohydroxamic acid (pbha) at ph 9-10 various parameters are studied to optimize the extraction conditions. the molar absorptivity is found to increase from ...

Journal: :Journal of analytical toxicology 2000
D L Allen J S Oliver

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...

2006
J. W. King

Optimizing the extracted analyte collection step in analytical supercritical fluid extraction (SFE) is of key importance in achieving high analyte recoveries and extraction efficiencies. Whereas the extraction step in SFE has been well characterized both theoretically and experimentally; the analyte collection step after SFE has few theoretical guidelines, aside from a few empirical studies whi...

Journal: :Journal of analytical toxicology 1997
K S Scott J S Oliver

A supercritical fluid extraction (SFE) procedure for the analysis of temazepam from whole blood was developed. Quantitative recoveries were obtained by high-performance liquid chromatography using prazepam as an internal standard and carefully monitoring the extraction temperature and pressure. The results were found to compare well with those obtained by solid-phase extraction techniques, but ...

Journal: :Journal of environmental quality 2010
Xiaoxuan Ma Yong Ran Jian Gong Diyun Chen

Sixteen USEPA priority polycyclic aromatic hydrocarbons (PAHs) extracted by Soxhlet extraction (S-PAHs) with dichloromethane and routine accelerated solvent extraction (A-PAHs) with 1:1 toluene/methanol, respectively, were investigated in 24 soil samples from two cities in the center of the Pearl River Delta, South China. Polycyclic aromatic hydrocarbons, methylphenanthrene and perylene, in two...

Abstract Polycyclic aromatic hydrocarbons (PAHs) are classified as persistent and carcinogenic organic pollutants. PAHs contamination has been reported in water. Many of relevant regulatory bodies such as EU and EPA have regulated the limit levels for PAHs in drinking water. In this study, 13 priority polycyclic aromatic hydrocarbons (PAHs) were determined in tap water samples of Tehran and wat...

Abstract Polycyclic aromatic hydrocarbons (PAHs) are classified as persistent and carcinogenic organic pollutants. PAHs contamination has been reported in water. Many of relevant regulatory bodies such as EU and EPA have regulated the limit levels for PAHs in drinking water. In this study, 13 priority polycyclic aromatic hydrocarbons (PAHs) were determined in tap water samples of Tehran and wat...

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