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Title: Analytical supercritical fluid extraction of adsorbent materials

Abstract

The use of supercritical fluids for the analytical extraction of semivolatile and higher molecular weight materials from various adsorbent and particulate matrices was investigated. Instrumentation was designed to allow gram quantities of the matrix to be extracted at pressures up to 400 bar and temperatures to 235 /sup 0/C with collection of the effluent in a sealed liquid-nitrogen-cooled flask. Carbon dioxide, isobutane, and methanol modified (20 mol %) carbon dioxide fluid systems were evaluated and compared to liquid Soxhlet extraction. Supercritical fluid extraction (SFE) provided very rapid (approx. =30 min) extraction with comparable efficiency to the Soxhlet methods, and both more rapid and more efficient extractions appear feasible. The more polar carbon dioxide-methanol fluid system gave higher extraction efficiencies for the more polar adsorbates and the isobutane system was more efficient for the higher molecular weight and less polar compounds.

Authors:
; ; ;
Publication Date:
Research Org.:
Pacific Northwest Lab., Richland, WA
OSTI Identifier:
7006321
DOE Contract Number:
AC06-76RL01830
Resource Type:
Journal Article
Resource Relation:
Journal Name: Anal. Chem.; (United States); Journal Volume: 59:1
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; 2-METHYLPROPANE; SOLVENT PROPERTIES; AIR; SOLVENT EXTRACTION; CARBON DIOXIDE; METHANOL; PARTICULATES; POLYCYCLIC AROMATIC HYDROCARBONS; EFFICIENCY; EXPERIMENTAL DATA; HIGH PRESSURE; HIGH TEMPERATURE; ALCOHOLS; ALKANES; AROMATICS; CARBON COMPOUNDS; CARBON OXIDES; CHALCOGENIDES; DATA; EXTRACTION; FLUIDS; GASES; HYDROCARBONS; HYDROXY COMPOUNDS; INFORMATION; NUMERICAL DATA; ORGANIC COMPOUNDS; OXIDES; OXYGEN COMPOUNDS; PARTICLES; SEPARATION PROCESSES; 400105* - Separation Procedures

Citation Formats

Wright, B.W., Wright, C.W., Gale, R.W., and Smith, R.D.. Analytical supercritical fluid extraction of adsorbent materials. United States: N. p., 1987. Web. doi:10.1021/ac00128a008.
Wright, B.W., Wright, C.W., Gale, R.W., & Smith, R.D.. Analytical supercritical fluid extraction of adsorbent materials. United States. doi:10.1021/ac00128a008.
Wright, B.W., Wright, C.W., Gale, R.W., and Smith, R.D.. 1987. "Analytical supercritical fluid extraction of adsorbent materials". United States. doi:10.1021/ac00128a008.
@article{osti_7006321,
title = {Analytical supercritical fluid extraction of adsorbent materials},
author = {Wright, B.W. and Wright, C.W. and Gale, R.W. and Smith, R.D.},
abstractNote = {The use of supercritical fluids for the analytical extraction of semivolatile and higher molecular weight materials from various adsorbent and particulate matrices was investigated. Instrumentation was designed to allow gram quantities of the matrix to be extracted at pressures up to 400 bar and temperatures to 235 /sup 0/C with collection of the effluent in a sealed liquid-nitrogen-cooled flask. Carbon dioxide, isobutane, and methanol modified (20 mol %) carbon dioxide fluid systems were evaluated and compared to liquid Soxhlet extraction. Supercritical fluid extraction (SFE) provided very rapid (approx. =30 min) extraction with comparable efficiency to the Soxhlet methods, and both more rapid and more efficient extractions appear feasible. The more polar carbon dioxide-methanol fluid system gave higher extraction efficiencies for the more polar adsorbates and the isobutane system was more efficient for the higher molecular weight and less polar compounds.},
doi = {10.1021/ac00128a008},
journal = {Anal. Chem.; (United States)},
number = ,
volume = 59:1,
place = {United States},
year = 1987,
month = 1
}
  • Supercritical fluid extraction (SFE) using eight different CO[sub 2] + organic modifier mixtures and one ternary mixture (CO[sub 2] + methanol/toluene) at two different concentrations (1 and 10% v/v) was performed on two certified reference materials including polychlorinated biphenyls (PCBs) from river sediment and polycyclic aromatic hydrocarbons (PAHs) from urban air particulate matter. The modifier identity was more important than modifier concentration for increasing extraction efficiencies. Acidic/basic modifiers including methanol, acetic acid, and aniline greatly enhanced the extraction of PCBs. Low molecular weight PAHs were best extracted with modifiers including aniline, acetic acid, acetonitrile, methanol/toluene, hexane, and diethylamine. In contrast,more » modifiers capable of dipole-induced dipole interactions and [pi]-[pi] interactions such as toluene, diethylamine, and methylene chloride were the best modifiers to use for SFE of high molecular weight PAHs from air particulates. 37 refs., 6 tabs.« less
  • The physical properties of supercritical fluids allow similar solvent strengths as liquids, but with higher diffusion coefficients, lower viscosities, and an extended temperature range that provides the potential for more-rapid and efficient extraction rates than possible with liquids. The report describes expanded studies conducted to evaluate the applicability and efficiency of analytical supercritical fluid extraction and related methodologies. These studies included the development of quantitative off-line supercritical fluid extraction methodology and a comparison to traditional Soxhlet extraction, the development and evaluation of on-line supercritical fluid extraction-gas chromatography for combined sample preparation and analysis, and direct supercritical fluid extraction-mass spectrometry formore » the monitoring of specific extraction profiles as a function of time. The sample matrices included an air particulate sample and XAD-2 resin, polyurethane foam, and Spherocarb adsorbents that were spiked with various model compounds. Carbon dioxide, isobutane, and methanol modified (20 mole %) carbon dioxide were utilized as supercritical fluid systems. Related studies on the evaluation of the quantitative analysis capability of a fluorescence detection supercritical fluid chromatography method and the development of viable solute focusing methods for capillary supercritical fluid chromatography were also conducted.« less
  • The report is a summary of work performed by PNL on the extraction of semivolatile organic materials (SVOCs), for example, polynuclear aromatic compounds, from various adsorbents and environmental matrices, using supercritical fluids (SCFs) as extractants. The results of the work show that supercritical fluids are effective extractants for many SVOCs, and are often competitive with conventional Soxhlet extraction. Advantages of SCFs over conventional methods include higher extraction efficiency, more rapid extraction, and reduced decomposition of thermally labile compounds.
  • In this review we examine the related fields of supercritical fluid chromatography (SFC) and supercritical fluid extraction (SFE). We reviewed the published literature in the period from November 2003 to November 2005. Well over 300 papers were published in this period. This large body of work indicates continuing active growth of the field, but an exhaustive review is beyond the scope of this work. We have chosen to include a sampling of publications that best represent the continuing trends and new ideas in the field. In keeping with past reviews on this subject1, we have broadened our scope to includemore » fluid systems operating at high temperature and pressure, but below the critical point. Various terms have been applied to this state: sub-critical fluid extraction, pressurized liquid extraction, and accelerated solvent extraction. The term accelerated solvent extraction has been used by instrument manufacturers to refer to this process, but we will use the more descriptive term pressurized liquid extraction (PLE) to refer to these systems. Most of the research in the field is of an “evolutionary” rather than “revolutionary” nature. As in the previous review period, applications papers make up a majority of the published work. Pharmaceutical applications continue to be a strong theme. Most of the pharmaceutical work has centered on preparative, rather than analytical, separations. Chiral separations are an exception, as analytical scale separations of chiral compounds are an area of intense interest. Food and natural products represent the next largest body of work. Major themes are the isolation and characterization of high-value added foodstuffs, fragrances, and flavor compounds from novel natural materials or agricultural by-products. The areas of food, natural products, and pharmaceutical separation science converge in the area of so-called nutraceuticals. These are typically high-value products, either sold alone or as part of a fortified food, that are regulated as food supplements but are intended to treat disease or maintain health. Antioxidants and beneficial lipid products are major examples in this category. The final major category consists of environmental applications, both as an extraction technique for environmental analysis, and as a possible remediation strategy for removing contaminants that would otherwise be too expensive to recover. Most of the work in this area has focused on non-polar compounds, such as polyaromatic hydrocarbons (PAHs) and poly-chlorinated biphenyls (PCB’s), where non-polar supercritical (SC) CO2 offers high extraction efficiencies. Co-solvent systems combining CO2 with one or more modifiers extend the utility of SC CO2 to polar and even ionic compounds. Supercritical water can extract polar compounds, and it has the additional advantage of combining extraction and destruction of contaminants via the supercritical water oxidation (SUWOX) process. Supercritical fluids are also useful in various niche applications. Fuel extraction, conversion, and analysis is one such application. Extraction of metals from various matrixes is also an area of continuing interest. The application of supercritical fluid (SCF) technology to production of nano-structured materials is a new area likely to see rapid growth in the next few years.« less
  • No significant differences have been found in the separation behavior of oligomers of monodisperse polystyrene samples when using n-pentane as the mobile phase and a phenyl or an n-octadecyl bonded stationary phase. For low-molecular weight polystyrenes used in this study, there was no evidence of steric exclusion effects when using non-derivatized silica. In all cases, the addition of either isopropanol or cyclohexane as a moderator was found to produce more nearly complete elution of the polystyrene oligomers from the stationary phases. Concentrations of isopropanol above 5% v/v caused no further change while increasingly higher percentages of cyclohexane caused capacity ratiosmore » of higher molecular weight species to decrease. Finally, non-linear pressure programming was found to produce more nearly regular elution of an oligomeric series while linear downward temperature programming was found to produce irregular elution behavior near the critical temperature. 14 figures, 2 tables.« less