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  • 1
    Electronic Resource
    Electronic Resource
    Gas chromatographic - mass spectrometric studies of long chain hydroxy acids. - III.1 The mass spectra of the methyl esters trimethylsilyl ethers of aliphatic hydroxy acids. A facile method of double bond location (1968)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 1 (1968), S. 593-611 
    Details
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Trimethylsilylation has proved to be extremely useful in the gas chromatography and the mass spectrometry of hydroxy acid methyl esters. The characteristic mass spectral fragmentation patterns have shown these derivatives to be superior in some respects to others for structural elucidation; in particular, hydroxylation followed by trimethylsilylation provides a useful method of double bond location in unsaturated fatty acid esters.A preliminary presentation of this method has been given by G. Eglinton at the Lecture etting in Combined Gas Chromatography - Mass Spectrometry at the school of Pharmacy, London, August 9, 1967. It has come to the authors' attention that this method simultaneously developed by Dr. P. Capella, Institute di Industria Agrarie, University of Bologna, Italy1c (P. Capella and C. M. Zorzut, Anal. Chem. 41, 1458 (1968).)
    Additional Material: 20 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/oms.1210010413
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  • 2
    Electronic Resource
    Electronic Resource
    Migration of dimethylsilyl substituents upon electron-impact: The fragmentation of methyl 12-dimethylsilyloxyoctadecanoate (1972)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 6 (1972), S. 909-916 
    Details
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Fragmentation of the dimethylsilyl (DMS) derivative of methyl 12-hydroxyoctadecanoate is found to be closely analogous to that of the previously studied trimethylsilyl (TMS) derivative, including migration of the silyl substituent from C-12 to the ester carboxyl function. besides establishing comparable migratory aptitudes of the TMS and DMS substituents, details of several other processes were revealed by use of deuterium labelling of selected positions and compared with related fragmentation of simple long-chain alcanoic esters.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/oms.1210060811
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Studies on the mass fragmentographic determination of plasma estriol (1974)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 1 (1974), S. 332-339 
    Details
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Three mass fragmentatographic methods for the determination of unconjugated estriol in pregnancy plasma and unconjugated and conjugated estriol in plasma of nonpregnant women after estriol administration were developed and tested as to their reliability and practicability. The methods were found to fulfil appropriate reliability criteria especially with regard to specificity. Unconjugated estriol could be assayed without prior chromatography in late pregnancy plasma, but a chromatographic step was needed for plasmas with a low estriol titre, and both a methylation step and chromatography is needed to achieve the required specificity if plasma conjugated estriol is determined or if assays are carried out following estriol administration. Unconjugated estriol in normal late pregnancy plasma was found in concentrations from 4.3 to 9.3 μg/l. The highest value recorded, 16.3 μg/l, was found in a prediabetic subject with mild hypertension, who delivered a child weighing 4150 g by Cesarean section in the 39th week. Low values were found in severe hypertension and in toxemia, and in general the results from the pathological material investigated seemed to correlate well with the clinical findings. However, only a few samples (five to ten) can be processed so rapidly that the results can be obtained the same day, which in addition to the expensive and complicated instrumentation limits the usefulness of the methods in routine clinical chemistry.
    Additional Material: 6 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200010508
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    Paper (German National Licenses)
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