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  • 1
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 17 (1994), S. 713-718 
    ISSN: 0935-6304
    Keywords: Electrophoretic capillary chromatography ; Organic modifiers ; Hydrophobic association ; Capacity factors ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Very good separations of non-ionic organic compounds have been achieved by capillary zone electrophoresis (CZE) using a tetrahep-tylammonium salt as an additive in aqueous acetonitrile as solvent. A systematic study was undertaken to determine the effect of experimental parameters on electroosmotic mobility and electro-phoretic mobility. It was found that pH, acetonitrile concentration, and the type and concentration of quaternary ammonium salt are important experimental variables. Under appropriate conditions, the separation window was enlarged and a broad range of electrically neutral organics, including very hydrophobic compounds (e. g. poly-cyclic aromatic hydrocarbons) and fairly hydrophilic compounds were separated in a relatively short time. By adjusting the separation conditions, high resolution CZE of a specific group of neutral organic compounds could be achieved. A method for calculation of capacity factor was proposed and capacity factors for a variety of non-lonic organic compounds were calculated.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 15 (1992), S. 569-569 
    ISSN: 0935-6304
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 13 (1990), S. 561-564 
    ISSN: 0935-6304
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 14 (1991), S. 656-660 
    ISSN: 0935-6304
    Keywords: Capillary GC ; Selectivity ; Compound group separation ; Clean-up ; Adsorption of basic compounds ; Sulfonated resin ; Quantitation ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A small amount of a lightly sulfonated non-porous resin placed in the liner of the injection splitter of a gas chromatograph retains basic organic compounds but allows neutral compounds to be chromatographed normally. The organic bases in the gaseous state react with sulfonic acid groups on the resin surface to form protonated ions. Abstraction of bases is complete at a base: neutral molar ratio as high as 200:1 and a large number of samples can be injected before the sulfonated resins need to be replaced.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 15 (1992), S. 605-608 
    ISSN: 0935-6304
    Keywords: Capillary GC ; Selectivity ; Compound group separation ; Clean-up ; Adsorption of sulfur compounds ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A small amount of mercuric non-porous resin placed in the liner of the injection splitter of a gas chromatograph retains mercaptans but allows other organic sulfur and non-sulfur compounds to be chromatographed normally: mercaptans in the gaseous state are retained by the mercuric resin. The method works well at 200°C but an increasing number of impurity peaks are observed as the temperature is increased to 250°C.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 0749-1581
    Keywords: 15N NMR ; Hydrazides ; 15N-1H coupling constants ; 13C-1H coupling constants ; Rotamer distribution ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Trifluoroacethydrazide is unstable even in the solid state with respect to hydrazonium N,N′-ditrifluoroacetyl hydrazinate, as shown by 15N and 13C NMR spectroscopy. The 1H, 13C and 15N NMR data and rotamer distributions of formyl-, acet- and trifluoroacet-hydrazide and of N,N′-diformyl-, N,N′-diacetyl- and N,N′-ditrifluoroacetyl-hydrazine are reported and compared with the results of earlier investigations. A conformational dependence is observed for 1J(NH) and 2J(NH) in the formylhydrazides and of 1J(NH), 2J(NH) 3J(NH) in the N,N′-diformylhydrazines. The conformational dependence of 2J(CH) in formamide, reported in the literature, however, could not be confirmed.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
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