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  • 1970-1974  (5)
  • 1965-1969  (3)
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  • 1
    Electronic Resource
    Electronic Resource
    Mass-spectrometric determination of metal chelates (1971)
    Springer
    Fresenius' Zeitschrift für analytische Chemie 257 (1971), S. 177-183 
    Details
    ISSN: 1618-2650
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Summary A rapid and accurate (3% rel.) mass-spectrometric determination of some poly-isotopic transition metals as their chelates with 2-thenoyltrifluoroacetone has been developed. The analysis of nanogram amounts of zinc, nickel and chromium has been accomplished using enriched stable metal isotopes as the internal standard. The mass spectra are generally well-defined and simple allowing simultaneous determinations in mixtures. The influence of other transition metals (Cu, Co, Fe and Mn) on the determination is discussed together with the analytical consequences of metal-metal chelate exchange reactions in the ion-source for determinations of iron and cobalt.
    Notes: Zusammenfassung Ein schnelles und genaues (3% rel.) massenspektrometrisches Verfahren zur Bestimmung von ng-Mengen Zink, Nickel und Chrom als Komplexe mit 2-Thenoyltrifluoraceton wird beschrieben. Als innerer Standard werden angereicherte stabile Metallisotope benutzt. Die Massenspektren sind im allgemeinen eindeutig und einfach, so daß sich auch gleichzeitige Bestimmungen in Gemischen durchführen lassen. Der Einfluß anderer Übergangsmetalle (Cu, Co, Fe und Mn) wird diskutiert zusammen mit den analytischen Konsequenzen von Metall-Metallkomplex-Austauschreaktionen in der Ionenquelle für die Bestimmung von Kobalt und Eisen.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00423909
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Mass-spectrometric determination of metal chelates (1970)
    Springer
    Fresenius' Zeitschrift für analytische Chemie 249 (1970), S. 296-301 
    Details
    ISSN: 1618-2650
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Summary A method has been developed for the determination of copper as copper acetylacetonate using electron-impact mass spectrometry with electrical detection. The use of completely deuterated copper acetylacetonate as an internal standard allows a simple and rapid determination. As might be expected, ligand exchange appears to occur, however without interfering effect. The determination is performed by comparing corresponding peak intensities of unknown and reference compounds. The accuracy and reproducibility in the nanogram range are about 3%. The method can be easily extended to the determination of other metals according to the same principle.
    Notes: Zusammenfassung Es wird über ein Verfahren zur Bestimmung von Nanogramm-Mengen Kupfer als Kupfer-Acetylacetonat unter Verwendung der Elektronenstoßionisations-Massenspektrometrie mit elektrischer Detektion berichtet. Die Anwendung von völlig Deuterium-markiertem Kupfer-Acetylacetonat als innerer Standard erlaubt eine einfache und schnelle Bestimmung. Wie erwartet, tritt bei der Anwendung dieses Standards ein beträchtlicher Ligandenaustausch auf, jedoch ohne Störung des Verfahrens. Zur Bestimmung erfolgt ein Intensitätvergleich der entsprechenden Peaks von unbekannter Probe und Standard. Die Genauigkeit und Reproduzierbarkeit der Methode liegen bei ungefähr 3% rel. Das Verfahren kann leicht zur Bestimmung anderer Metalle ausgebaut werden.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00456859
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    The electron-impact-induced fragmentation of n-alkyl cyanides (1969)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 2 (1969), S. 1103-1115 
    Details
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The mass spectra of the alkyl cyanides up to n-pentyl cyanide were studied. Using metastablel ion transitions, appearance potentials and deuterium labelling, the fragmentation patterns, spectral characteristics and trends for this series can be given. The investigation of labelled compounds demonstrates the specificity of rearrangement and normal decomposition processes. Alkyl ions in nitriles are produced by simple cleavage of the carbon-carbon bond, while ions of the type [M -alkyl]+, which at the first sight could originate in the same way, are presumably formed via cyclic intermediates and are in fact rearrangement ions.Apart from the known γ and δ-hydrogen rearrangements, there is novel evidence for a β-hydrogen rearrangement via a five-membered ring transition state.
    Additional Material: 7 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/oms.1210021108
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  • 4
    Electronic Resource
    Electronic Resource
    Ion-molecule reactions in alkyl cyanides: Identification of reactive hydrogen in precursor ions (1970)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 3 (1970), S. 379-386 
    Details
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The relative abundance of [M + H]+ ions in the spectra of different nitriles depends on the nature of the nitrile. A new method for the identification of ion-molecule reactions has been applied, by determining the [M + D]+ ion intensity with respect to the [M + H]+ ion intensity in the spectra of partially deuteriated alkyl cyanides. This intensity ratio is correlated with the hydrogen-deuterium content of the suspected primary ions. In addition not only the reacting primary ions, but also the reactive hydrogen atom in the primary ion could be indicated. There is clear evidence that the proton attached to the nitrogen atom in the H2C=C=N+·—H rearrangement ion is transferred to the nitrile molecule.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/oms.1210030312
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    Paper (German National Licenses)
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  • 5
    Electronic Resource
    Electronic Resource
    Pattern recognition. An application to the identification of some stereoisomeric N-acetylhexosamines by mass spectrometry (1974)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 9 (1974), S. 536-547 
    Details
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A method is reported for the identification of trimethylsilylated stereoisomeric N-acetyl-hexosamines by application of a pattern recognition procedure to mass spectral data. The selection of characteristic mass spectral data and the pattern recognition procedure are discussed.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/oms.1210090511
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    Paper (German National Licenses)
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  • 6
    Electronic Resource
    Electronic Resource
    The electron-impact-induced fragmentation of some alkyl isocyanides and α-branched alkyl cyanides (1970)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 3 (1970), S. 1439-1456 
    Details
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The HRP mass spectra of some alkyl isocyanides (R—NC in which R equals CH3, C2H5, n-C3H7, n-C4H9 and t-C4H9) and two methyl branched alkyl cyanides (R—CN in which R equals i-C3H7 and t-C4H9) have been studied. Using metastable ion transitions and appearance potentials, the fragmentation patterns and spectral characteristics of the isocyanides can be given. A comparison has been made with the mass spectral data of the corresponding cyanides.Although the mass spectra of alkyl cyanides and isocyanides show close relationship, evidence could be obtained that this resemblance is not caused by rearrangement of the isocyanide into cyanide molecules. The main difference between the spectra of both compounds is caused by the strength of the α-bond, being weaker in the case of the isocyanides. The abundance of ions formed by α-bond cleavage decreases with increasing size of the alkyl group.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/oms.1210031113
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    Paper (German National Licenses)
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  • 7
    Electronic Resource
    Electronic Resource
    Amino-acid sequence study in peptides by mass spectometry-IIFor Part I see Ref. 3.. Investigation of pentadeuterobenzoyl-peptide methyl esters (1968)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 1 (1968), S. 345-350 
    Details
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The utility of benzoyl and pentadeuterobenzoyl derivatives of peptide methyl esters for mass spectrometric analysis was investigated. The mass spectra of the glu-his and the val-tyr-pro derivatives are discussed. Treatment of the peptide methyl esters with the mixed benzoic-ethyl-carbonic anhydride did in some cases lead to benzoyl derivatives as well as to ethoxycarbonyl derivatives.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/oms.1210010304
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    Paper (German National Licenses)
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  • 8
    Electronic Resource
    Electronic Resource
    Amino-acid sequence study in peptides by mass spectometry - IIIIn Part II see preceding paper. Investigation of ethyoxycarbonyl-peptide methyl esters (1968)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 1 (1968), S. 351-364 
    Details
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The utility of ethoxycarbonyl-peptide methyl esters for mass spectrometric analysis is described. The ethoxycarbonyl group has important advantages over other protecting groups which are in use. The derivatives have high intensity; this greatly facilitates the interpretation of the fragmentation pattern. The spentra of the methyl esters of the ethoxycarbonyl derivatives of pro-val, trp-gly, gly-ser, (cys)2, glutation (GSH), glu-his-phe, val-tyr-pro and val-lys-val-tyr-pro are given.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/oms.1210010305
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    Paper (German National Licenses)
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