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  • 1
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 10 (1987), S. 137-140 
    ISSN: 0935-6304
    Keywords: Liquid chromatography, Micro-HPLC ; Purpurea glycosides ; Digitalis purpurea ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A micro high-performance liquid chromatographic (micro-HPLC) method was developed for the determination of purpurea glycoside A, purpurea glycoside B, and glucogitaloxin in Digitalis purpurea leaves. The extract of dry leaf powder was applied to a Sep-Pak silica cartridge followed by preparative thin-layer chromatography prior to micro-HPLC analysis. The analysis was performed on an ODS micro column, using acetonitrile-methanol-water (21:20:45) and ultraviolet detection (220 nm). The amounts of purpurea glycoside A, purpurea glycoside B, and glucogitaloxin per 100 mg of dry leaf powder were estimated to be 52.6, 50.7, and 108.6 μg, respectively.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
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  • 2
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 544 (1987), S. 7-20 
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zur Struktur von GraphitfluoridDie Struktur von Graphitfluorid, (C2F)n, wurde mittels Röntgenanalyse, 19F-Festkörper-NMR und Elektronenmikroskopie an gut charakterisierten und kristallisierten Proben von natürlichem Graphit und HOPG (highly oriented pyrolytic graphite) untersucht. Aufgrund dieser Ergebnisse und den in vorhergehenden Arbeiten erhaltenen strukturellen Eigenschaften hat (C2F)n eine Schichtstruktur der 2. Stufe, die zum hexagonalen System mit der Symmetrie C3h gehört. Detallierte Diskussionen zur Symmetrie sowohl für (CF)n wie für (C2F)n haben zur möglichen Stapelsequenz geführt, die jede Einheitszelle des Graphitfluorids erfordern sollte. Die Idealstruktur ist ein hexagonales Kristallgitter mit a = b 2,5 Å; c = 16,2 Å und einer plausiblen Stapelsequenz von AB/B′A′/ mit der Identitätsperiode Ic = 8,09 Å. Die Schichtstruktur von (CF)n ist von 1. Stufe mit der Stapelsequenz A/A′/.
    Notes: The structure of graphite fluoride, (C2F)n has been investigated by X-ray analyses, solid state 19F-n.m.r., and electron microscopy for well characterized and crystallized samples obtained from natural graphite or HOPG (highly oriented pyrolytic graphite). On the basis of the present results and structural properties derived from previous works, (C2F)n has a layered structure of stage-2 which belongs hexagonal to the system with C3h symmetry. Detailed discussions on the symmetry both for (CF)n and (C2F)n have led to possible stacking sequences each unit cell of graphite fluoride should require. The ideal structure of (C2F)n is a hexagonal crystal lattice with a = b = 2.5 Å; c = 16.2 Å, and a plausible stacking sequence of AB/B′A′/ with Ic (identity period) = 8.09 Å. The layered structure of (CF)n is of stage-1 with A/A′/ stacking sequence.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
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