Search results for "upe"

Determination of alinidine in human plasma by high-performance liquid chromatography.

1981

Supercritical fluid extraction of pesticides

1989

The extraction behaviour of 10 μg samples of five pesticides and some related compounds from glass wool with supercritical CO2 has been investigated under several conditions (10 MPa, 20 MPa extraction pressure, 313 K, dry and water saturated CO2). The extraction fluid was decompressed over a line of little columns, filled with 3μ Si60 or RP18, and the amount of deposited material was analyzed by HPLC for each of these columns. Due to the progressive pressure/density reduction along the line, the solubility diminishes and hence the compounds are deposited according to their polarity/vapor pressure earlier or later on the line. Thus extraction and prefractionation of compounds of different po…

Role of Phase Behavior and Atomization in the Supercritical Antisolvent Precipitation

2003

An experimental study on supercritical antisolvent (SAS) precipitation has been performed to gain insight into the role of phase behavior and atomization in controlling morphology and dimension of precipitates. The mixture yttrium acetate/dimethyl sulfoxide has been used as the main model system and supercritical CO 2 has been used as the antisolvent. Two SAS apparatuses (laboratory and pilot scale) with two injector arrangements and operating with various injector diameters in the range 60-500 μm have been used. The results showed that operating above the mixture critical point (MCP) of the ternary mixture yttrium acetate/dimethyl sulfoxide/ carbon dioxide, sub-micrometric particles are ge…

High-pressure solubility data of system ethanol (1)+catechin (2)+CO2 (3)

2001

Abstract Supercritical fluid extraction posses several advantages over traditional liquid–solvent-based extraction methods including improved selectivity, expeditiousness, automation and environmental safety. Fluid phase equilibrium data is essential for study the viability of supercritical extraction and the design of the extraction columns often used for this type of separations. During the past few years it has been demonstrated that phenolic compounds, such catechins and procyanidins from seeds, contribute to both the flavour properties and the pharmacological effects of wine. The extraction of catechin using supercritical CO2 is not possible, it only extracts traces of product, probabl…

High-pressure solubility data of the system resveratrol (3)+ethanol (2)+CO2 (1)

2001

Abstract Supercritical fluid extraction possesses several advantages over traditional liquid-solvent-based extraction methods, including improved selectivity, expeditiousness, automation and environmental safety. Fluid-phase equilibrium data are essential for studying the viability of supercritical extraction and the design of the extraction columns often used for this type of separation. Resveratrol has been correlated with serum lipid reduction and inhibition of platelet aggregation, and its cancer chemopreventive activity has recently been reported. The extraction of resveratrol using supercritical CO 2 is not possible; it only extracts traces of product, probably due to its polar nature…

Experimental and fluid dynamic study of continuous supercritical water gasification of glucose

2016

Abstract The supercritical water gasification (SCWG) of glucose as a model compound for H 2 production is studied in term of process development at 25 MPa and 650 °C. Gasification has been investigated using a laboratory scale continuous plant comprising a continuous down flow reactor with a volume of 200 cm 3 , a heat recovery section and pre-heat of the biomass to simulate more closely an industrial design. Feed streams (pure water and glucose solution) are introduced at the top of the vessel and products are extracted from the bottom. The reactor is equipped with various inlet points that allow to modify the inlet position of reacting streams in order to study the effect of stream mixing…

Study of kinetics of the d-pinitol extraction from carob pods using supercritical CO2

2014

Abstract There is a growing interest in the use of d -pinitol ( d -3-O-methyl-chiro-inositol) as a food supplement, thus the use of green and efficient process, such as the supercritical fluid extraction (SFE), to isolate d -pinitol from vegetable raw materials is also an interesting area of research and development. The objective of this work was to study the influence of operating conditions on the SFE of d -pinitol from carob pods. The crucial parameters in SFE, like temperature, pressure, CO 2 flow rate and duration of the process, have been studied. Finally, Naik and Barton models have successfully tested in order to fit the experimental extraction curves.

Pressurized liquid extraction of organic contaminants in environmental and food samples

2015

Pressurized liquid extraction (PLE) is an automated technique that uses elevated temperature and pressure to achieve exhaustive extraction from solid matrices, so reducing solvent consumption and enhancing sample throughput when compared with traditional procedures. Hence, it can be considered an environment-friendly technique, generating small volumes of waste and reducing costs and time. This review focuses on application of this green technique to the analysis of organic contaminants in food and environmental matrices for monitoring purposes. We examine fundamentals and key aspects of the development of a PLE method, including pressurized hot-water extraction, together with some relevant…

Determination of pesticides and their degradation products in soil: critical review and comparison of methods

2004

18 páginas, 5 figuras, 5 tablas.

Supercritical CO2 extraction of essential oils from orange peel

1996

The supercritical fluid extraction of orange essential oil was studied using dehydrated orange peel (0.0538 kg H2O kg−1 dm) from naveline cultivars as raw material and CO2 as solvent. The effect of operation conditions was analyzed in a series of experiments at 313 and 323 K and pressures between 1 and 25 MPa. Furthermore, the effect of CO2 flow rate and particle size of orange peel was studied in the range of 0.5 to 3.5 kg h−1 and 0.1 to 10 mm. The subcritical CO2 dissolves hardly any essential oils, however, on reaching the critical point, the amount of essential oils dissolved increased with pressure, within the range of pressures considered in this study. Increasing solvent mass flow de…