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  • 1
    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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  • 2
    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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  • 3
    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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  • 4
    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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