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| 2. |
- Haglund, Peter, et al.
(author)
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A modular approach to pressurized liquid extraction with in-cell clean-up
- 2010
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In: LC GC Europe. - Duluth, MN : Advanstar Communications, Inc.. - 1471-6577. ; 28:7, s. 544-
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Journal article (peer-reviewed)abstract
- A new concept for the extraction of solid samples has been developed. The popular pressurized liquid extraction (PLE) technique has been modified so that the extraction cell can be divided, which greatly increases the flexibility and versatility of this technique. The system uses simple adaptors to couple commercially available extraction cells, which may be loaded with either sample or adsorbent(s). These segmented extraction cells make it possible to selectively retain analytes or matrix to achieve simultaneous extraction and clean-up or fractionation. The ultimate aim is to perform simultaneous extraction and clean-up and obtain a purified extract that is ready for instrumental analysis, all in line with current trends in analytical chemistry to automate and streamline the analytical procedures to reduce the analysis costs, solvent consumption, manual labour and increase the quality of analysis. Selected modes of operations are presented and a few recent environmental applications of modular PLE are reviewed.
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| 3. |
- Haglund, Peter, et al.
(author)
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A Modular Approach to Pressurized Liquid Extraction with In-Cell Cleanup
- 2011
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In: LC GC North America. - : Advanstar Communications. - 1527-5949 .- 1939-1889. ; :Suppl., s. 66-72
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Journal article (peer-reviewed)abstract
- A new concept for the extraction of solid samples has been developed. The popular pressurized liquid extraction (PLE) technique has been modified so that the extraction cell can be divided, which greatly increases the flexibility and versatility of this technique. The system uses simple adapters to couple commercially available extraction cells, which can be loaded with either sample or adsorbents. These segmented extraction cells make it possible to selectively retain analytes or matrix to achieve simultaneous extraction and cleanup or fractionation. The ultimate aim is to perform simultaneous extraction and cleanup and obtain a purified extract that is ready for instrumental analysis, all in line with current trends in analytical chemistry to automate and streamline the analytical procedures to reduce the analysis costs, solvent consumption, and manual labor, and increase the quality of analysis. Selected modes of operations are presented and a few recent environmental applications of modular PLE are reviewed.
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| 6. |
- Nording, Malin, et al.
(author)
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Analysis of dioxins in contaminated soils with the calux and caflux bioassays, an immunoassay, and gas chromatography/high-resolution mass spectrometry
- 2007
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In: Environmental Toxicology & Chemistry. ; 26:6, s. 1122-9
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Journal article (peer-reviewed)abstract
- The chemically activated luciferase expression assay, the chemically activated fluorescence expression assay, and the enzyme-linked immunosorbent assay (ELISA) are all bioanalytical methods that have been used for the detection and quantification of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs). However, no comparisons of the results obtained by these three methods have been published analyzing identical replicates of purified sample extracts. Therefore, we have evaluated the performance of each of these methods for analyzing PCDD/Fs in aliquots of extracts from aged-contaminated soil samples and compared the results with those obtained by gas chromatography/high-resolution mass spectrometry (GC/HRMS). The quantitative performance was assessed and the effects of sample purification and data interpretation on the quality of the bioassay results were investigated. Results from the bioanalytical techniques were, in principle, not significantly different from each other or from the GC/HRMS data (p = 0.05). Furthermore, properly used, all of the bioanalytical techniques examined were found to be sufficiently sensitive, selective, and accurate to be used in connection with soil remediation activities when aiming at the remediation goal recommended by the U.S. Environmental Protection Agency (i.e., <1000 pg toxic equivalency/g). However, a site-specific correction factor should be applied with the use of the ELISA to account for differences between the toxic equivalency factors and the ELISA cross-reactivities of the various PCDD/F congeners, which otherwise might significantly underestimate the PCDD/F content.
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| 7. |
- Nording, Malin, et al.
(author)
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Rapid screening of dioxin-contaminated soil by accelerated solvent extraction/purification followed by immunochemical detection
- 2006
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In: Analytical and Bioanalytical Chemistry. - : Springer Science+Business Media B.V.. - 1618-2642 .- 1618-2650. ; 385:2, s. 357-366
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Journal article (peer-reviewed)abstract
- Since soils at industrial sites might be heavily contaminated with polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs), there is a need for large-scale soil pollution surveys and, thus, for cost-efficient, high-throughput dioxin analyses. However, trace analysis of dioxins in complex matrices requires exhaustive extraction, extensive cleanup, and very sensitive detection methods. Traditionally, this has involved the use of Soxhlet extraction and multistep column cleanup, followed by gas chromatography-high-resolution mass spectrometry (GC/HRMS), but bioanalytical techniques may allow much more rapid, cost-effective screening. The study presented here explores the possibility of replacing the conventional method with a novel approach based on simultaneous accelerated solvent extraction (ASE) and purification, followed by an enzyme-linked immunosorbent assay (ELISA). Both the traditional and the novel cleanup and detection approaches were applied to contaminated soil samples, and the results were compared. ELISA and GC/HRMS results for Soxhlet-extracted samples were linearly correlated, although the ELISA method slightly underestimated the dioxin levels. To avoid an unacceptable rate of false-negative results, the use of a safety factor is recommended. It was also noted that the relative abundance of the PCDDs/PCDFs, evaluated by principal component analysis, had an impact on the ELISA performance. To minimize this effect, the results may be corrected for differences between the ELISA cross-reactivities and the corresponding toxic equivalency factor values. Finally, the GC/HRMS and ELISA results obtained following the two sample preparation methods agreed well; and the ELISA and GC/HRMS results for ASE extracts were strongly correlated (correlation coefficient, 0.90). Hence, the ASE procedure combined with ELISA analysis appears to be an efficient approach for high-throughput screening of PCDD-/PCDF-contaminated soil samples.
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