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  • 1
    Electronic Resource
    Electronic Resource
    Micellar electrokinetic capillary chromatography of algal toxins (1997)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 20 (1997), S. 34-38 
    Details
    ISSN: 0935-6304
    Keywords: Micellar electrokinetic capillary chromatography, MECC ; Algal toxins ; Microcystin LR, YR, RR ; Nodularin ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Recent methods employed for the analysis of algal toxins have focused on high performance liquid chromatography. However these methods suffer from poor resolution, poor efficiency, and long analysis times. This study involves the investigation of a number of toxins including nodularin, microcystin LR, YR, and RR which are cyclic peptides produced by strains of blue-green algae. The electroseparation mode was micellar electrokinetic capillary chromatography (MECC) using a borate buffer containing sodium dodecyl sulfate (SDS) as the surgactant of choice. The method was optimized with standard toxin compounds and employed for the screening opf toxins in supercritical fluid extracts (SFE) of freeze-thawed algal scum samples.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jhrc.1240200107
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  • 2
    Electronic Resource
    Electronic Resource
    Unified multidimensional microcolumn chromatography (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Microcolumn Separations 1 (1989), S. 63-70 
    Details
    ISSN: 1040-7685
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mcs.1220010205
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  • 3
    Electronic Resource
    Electronic Resource
    Modifier addition in microcolumn supercritical fluid chromatography (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Microcolumn Separations 7 (1995), S. 375-381 
    Details
    ISSN: 1040-7685
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Recent advances in techniques for the packing of microcolumns of down to 50 μm inner diameter using supercritical CO2 have led to rapid growth in the use of high efficiency packed capillary columns in SFC. Maximization of the usefulness and applications of these techniques requires gradient elution chromatography and the development of pumps capable of delivering 0.1 to 1 μl per minute of modifier. A micro SFC-LC pump has been tested in the isocratic and gradient elution mode with CO2 as the supercritical fluid and methanol as the modifier. The pump was tested using the EPA priority PAHs as the test mixture with a specially treated ODS column and UV detection. Results are presented for testing in the isocratic and gradient elution modes and the retention times are shown to have a coefficient of variation of less than 2%. The application of this system to the analysis of PAHs in coal derivatives is shown. The problems encountered in the use of formic acid as a modifier in SFC are discussed. © 1995 John Wiley & Sons, Inc.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mcs.1220070410
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  • 4
    Electronic Resource
    Electronic Resource
    Microcolumn supercritical fluid chromatography with on-line Fourier transform infrared detection (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Microcolumn Separations 1 (1989), S. 101-109 
    Details
    ISSN: 1040-7685
    Keywords: capillary supercritical fluid chromatography ; Fourier transform infrared spectrometry ; flow cell ; ultraviolet curing inks and coatings ; carbon dioxide ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The combination of capillary supercritical fluid chromatography (SFC) and Fourier transform infrared spectrometry (FTIR) is demonstrated using a low-volume (0.8 μL) flow cell capable of withstanding high pressures. The design of the interface is presented, and its effect on peak shape and detector sensitivity is discussed. In order to optimize the system for use with 50-μ i.d. capillary columns, makeup fluid is added to the column effluent before it passes through the flow cell to a flame ionization detector (FID). Loss in chromatographic resolution caused by the cell's dead volume is therefore minimized, which is clearly demonstrated by the analysis of two ultraviolet curing coatings using carbon dioxide as a mobile phase. This application highlights the analytical power of the system for separating and identifying reactive monomers, oligomers, and photoinitiators in low- to medium-molecular-weight polymer systems.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mcs.1220010210
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  • 5
    Electronic Resource
    Electronic Resource
    Xenon as a mobile phase in supercritical fluid chromatography (1991)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Microcolumn Separations 3 (1991), S. 337-347 
    Details
    ISSN: 1040-7685
    Keywords: supercritical fluid chromatography ; mobile phases ; xenon ; SFC-FTIR ; polynuclear aromatic hydrocarbons ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Supercritical xenon and CO2 are compared as solvents by means of solubilities (calculated by means of the Peng-Robinson equation of state) and chromatographic behavior for some polynuclear aromatic hydrocarbons; reasons for the apparent superiority of xenon are discussed. The advantages of the use of xenon as a mobile phase in coupled supercritical fluid chromatography-Fourier transform infrared spectrometry are evaluated from analyses of monomer and oligomer mixtures.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mcs.1220030408
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  • 6
    Electronic Resource
    Electronic Resource
    Stopped-flow FTIR detection in capillary supercritical fluid chromatography (1990)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Microcolumn Separations 2 (1990), S. 300-303 
    Details
    ISSN: 1040-7685
    Keywords: capillary supercritical fluid Chromatography ; Fourier transform infrared spectrometry ; flow cell ; stopped flow ; polymer additives ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A stopped-flow procedure for capillary supercritical fluid Chromatography with Fourier transform infrared detection is described. The flow of mobile phase is stopped so that the analyte peak is held under liquid conditions in the flow cell while FTIR scans are recorded. An increase in the IR spectrum signal-to-noise ratio is demonstrated during the analysis of a polymer additive.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mcs.1220020608
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  • 7
    Electronic Resource
    Electronic Resource
    Electrospray micro liquid chromatography - Fourier transform infrared micro spectrometry (1992)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 15 (1992), S. 361-366 
    Details
    ISSN: 0935-6304
    Keywords: Micro liquid chromatography ; Electrospray nebulization ; Fourier transform infrared (FTIR) ; Micro spectroscopy ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Microcolumn liquid chromatography has been interfaced with infrared microspectrometry by means of a novel technique involving electrospray nebulization. The eluent from the LC column is subjected to a high positive potential relative to the surroundings and the electric field generated charges the surface of the emerging liquid causing it to disintegrate into charged droplets which are attracted to an earthed, infrared-transparent, zinc selenide deposition plate. Nitrogen sheath gas is used to evaporate the solvent in the droplets, and the separated components are deposited on the zinc selenide plate for subsequent analysis by means of a Fourier transform infrared microscope and spectrometer. Provided low flow rates (∼4 μl/min) are used, total elimination of the solvent is achieved and easily identifiable infrared spectra can be measured from less than 500 pg of sample (caffeine).
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jhrc.1240150602
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  • 8
    Electronic Resource
    Electronic Resource
    Capillary supercritical fluid chromatography of limonoids (1993)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 16 (1993), S. 469-472 
    Details
    ISSN: 0935-6304
    Keywords: Supercritical fluid chromatography ; Capillary column ; Carbon dioxide ; Limonoid ; Entandrophragma delevoyii ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Capillary supercritical fluid chromatography (SFC) with carbon dioxide as the mobile phase has been used to separate a mixture of limonoid standards. Chromatographic conditions were optimized to enable analysis of plant extracts. The seed of Aphanamixis polystacha (Meliaceae) and the stem bark of Harpephyllum caffrum (Anacardiaceae) were extracted with hexane and the extracts were analyzed by SFC to demonstrate the potential of the technique as a screening tool. SFC analysis indicated the presence of limonoids in the hexane extract of the bark of Entandrophragma delevoyii (Meliaceae). One limonoid and two protolimonoids isolated from the extract were separated by SFC.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jhrc.1240160805
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  • 9
    Electronic Resource
    Electronic Resource
    Open tubular supercritical fluid chromatography of triterpene acids from Dysoxylum pettigrewianum (Meliaceae) (1995)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 18 (1995), S. 363-366 
    Details
    ISSN: 0935-6304
    Keywords: Supercritical fluid chromatography ; Open tubular column ; Carbon dioxide ; Dysoxylum pettigrewianum (Meliaceae) ; Dysoxylic acid ; Liquid crystalline stationary phase ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Open tubular supercritical fluid chromatography (SFC) with carben dioxide as the mobile phase has been investigated for the separation of four triterpene acids, two of which were structural isomers. These compounds, isolated from Dysoxylum pettigrewianum (Meliaceae), were chromatographed on three stationary phases with different selectivities. 30%-biphenylmethylpolysiloxane and polyethylene glycol (Carbowax 20M) phases exhibited poor chromatographic selectivity for the compounds. The separation was improved by employing the shape selectivity of a liquid crystalline biphenylcarboxylate ester polysiloxane and utilizing simultaneous temperature and pressure programming. The elution order was explained on the basis of the molecular structures of the triterpene acids, and their interaction with the liquid crystal phase.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jhrc.1240180608
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  • 10
    Electronic Resource
    Electronic Resource
    On-line capillary supercritical fluid chromatography-inductively coupled plasma mass spectrometry for the analysis of organometallic compounds (1995)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 18 (1995), S. 33-37 
    Details
    ISSN: 0935-6304
    Keywords: Capillary supercritical fluid chromatography ; Inductively coupled plasma-mass spectrometry ; On-line SFC-ICPMS ; Organometallic compounds ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Supercritical fluid chromatography with inductively coupled plasma-mass spectrometric detection is a new and useful technique for the analysis of organometallic compounds. An interface has been developed for coupling these techniques. The interface is compact, easy to assembel, and causes minimal disruption to either instrument. A series of organotin, organoarsenic, and organorion compounds has been used to evaluate the interface and ICPMS as a detector for SFC. The effect of analyte concentration and restrictor temperature on peak intensity has been investigated and the effect of the mobile phase on the plasma has also been studied to assess background interference from changes in the plasma.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jhrc.1240180108
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