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  • 1
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    Journal of chemical information and modeling 34 (1994), S. 179-183 
    ISSN: 1520-5142
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    European food research and technology 192 (1991), S. 19-23 
    ISSN: 1438-2385
    Source: Springer Online Journal Archives 1860-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Description / Table of Contents: Summary Eighteen chemical and physical parameters of nectar and honeydew honeys were determined and the results were analysed statistically by the method of principal component analysis. On the plots of principal component loadings, the honeys were divided into the following groups: (1) acacia honey; (2) rape honey; (3) linden, floral (nectar coming from various plants) and heather honeys; (4) honeydew honey. The samples which were a blend of nectar and honeydew honeys may be considered as a separate group between 3 and 4. The most important first principal component was strongly associated with the value of electrical conductivity, the contents of ash, free acids and proline, as well as with the pH and the diastase number. The principal component loadings and linear correlation suggested that these parameters contributed much more to the classification of honeys than apparent reducing sugars, apparent sucrose, mono-, di-, and trisaccharides, glucose and fructose. The classification of honeys by the method of principal component analysis may serve as an additional tool in specifying samples on the basis of their chemical composition.
    Notes: Zusammenfassung 18 chemische und physikalische Parameter der Nektar- und Honigtauhonige wurden bestimmt und die Ergebnisse statistisch mit Hilfe der Hauptkomponentenanalyse ausgewertet. Danach konnten die Honige in folgende Gruppen unterteilt werden: 1) Akazienhonige, 2) Rapshonige, 3) Linden-, Blüten-und Heidehonige, 4) Honigtauhonige. Zwischen dem Nektarhonig und Honigtauhonig lagen wahrscheinlich die Proben von Mischhonigen aus Blüten- und Waldtracht. Die bedeutendste erste Hauptkomponente war mit folgenden Parametern verbunden: elektrischer Leitfähigkeitswert und Aschegehalt, Gehalt an freien Säuren und Prolin sowie der pH-Wert und Diastasezahl. Aufgrund der Hauptkomponentenladungen und der linearen Korrelation kann angenommen werden, daß diese Parameter für die Honigklassifizierung von größerer Bedeutung sind als der Gehalt an reduzierenden Zuckern, scheinbarer Saccharose, Mono-, Di- und Trisaccharide, Glucose und Fructose. Die Klassifizierung der Honige mit Hilfe der Hauptkomponentenanalyse kann bei der Spezifikation einer Honigprobe aufgrund ihrer chemischen Zusammensetzung von Nutzen sein.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 16 (1981), S. 328-329 
    ISSN: 0030-493X
    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
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  • 4
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 16 (1981), S. 375-375 
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 16 (1981), S. 52-52 
    ISSN: 0030-493X
    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
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  • 6
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 2 (1989), S. 232-242 
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Characteristic vector analysis of a set of six physical and empirical parameters of 103 commonly used organic solvents (bp, ∊r, μ, nD, ETN, and δ) gives four vectors describing 95% of the total data variability. Non-hierarchical cluster analysis, applied to our results, leads to ten separate classes of organic solvents.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 30 (1992), S. 45-57 
    ISSN: 0749-1581
    Keywords: 13C NMR substituent effects ; Principal component analysis ; Electronegativity correlation ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Principal component (PC) or factor analysis was applied to 13C substituent effects (literature SCS values) in α to δ positions of 47 aliphatic frameworks with 4-13 different substituents X. Two PC terms for each substituent X are sufficient to describe 99.3% of all C-α shifts within 〈 ± 0.6 ppm, even in the largest data matrix containing 13 × 47 = 611 shifts; shifts in β. γ and δ positions require a third PC term for a similar percentage SCS accuracy. Scaling problems with the different order of magnitudes between α to δ SCS variations are avoided by analysing the corresponding data sets separately; this approach, together with the large data base, leads to a dominating first PC term for C-α which unambiguously correlates with substituent electronegativities (EN), in contrast to an earlier factor analysis. The same result is obtained by direct comparison of α-SCS with different EN scales, including for the first time group electronegativities. PCs for β to γ SCS indicate only less consistent trends, which again agree partially with results from direct correlations, but not with EN values. The present PC analysis did not include stereochemical descriptors, but furnishes clear distinctions between clusters of (pseudo-) equatorially or axially substituted compounds. The PC loadings for C-α also lead to the unambiguous distinction of primary, secondary, tertiary and quaternary carbon atoms.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
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