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  • Electronic Resource  (31)
  • Analytical Chemistry and Spectroscopy  (17)
  • General Chemistry  (9)
  • Organic Chemistry  (5)
  • 1
    Electronic Resource
    Electronic Resource
    π-Orbital Interactions in Möbius-Type Molecules as Studied by Photoelectron Spectroscopy (1982)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 65 (1982), S. 1743-1751 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Some benzobarrelenes were studied by photoelectron (PE.) spectroscopy. The results can be interpreted by considering dominant through-space interaction of the π-molecular fragments in a Möbius-fashion, Some chemical features of the substrates are rationalized on the basis of these findings.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19820650609
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  • 2
    Electronic Resource
    Electronic Resource
    De l'action de quelques chlorures dérivés de l'acide carbonique sur la diméthylaniline (1925)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 8 (1925), S. 490-500 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19250080174
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  • 3
    Electronic Resource
    Electronic Resource
    Mechanisms of Diazo Coupling Reactions. Part XXXII. The Diazoamino Rearrangement in 20% Acetonitrile/Aqueous BuffersPart XXXI: [1]. (1982)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 65 (1982), S. 122-132 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The rearrangements of 4′-methoxy-N-methyl- and N-methyl-4′-nitro-diatzoaminobenzene have been studied in 20% acetonitrile/aqueous buffers. The reactions are specifically acid catalyzed and involve pre-equilibrium formation of amine and diazonium salt followed by rate-limiting attack of the diazonium ion at a C-atom (C-coupling) to give the corresponding aminoazo compounds. There is no evidence to suggest that, under the present conditions, mechanisms other than the established Friswell-Green mechanism occur. The traditional two-stage synthesis of aminoazo compounds via isolated diazoamino compounds can therefore be replaced by a one stage process for amines which undergo initial attack at a N-atom by diazonium ion (N-coupling).
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19820650112
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  • 4
    Electronic Resource
    Electronic Resource
    Transport Properties of H+-Selective Membranes Containing Amine-Derivative Ionophores and Mobile Sites (1993)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 76 (1993), S. 407-415 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Transport processes in plasticized PVC membranes containing the H+ chromoionophore ETH 5294 and additional tetraphenylborate-type mobile sites were analyzed by employing the potential-step method. Using chronoamperometry, impedance spectroscopy, and UV/VIS absorbance measurements, it is shown that the ionophore behaves as a carrier for protons, when the membranes are immersed between two aqueous solutions. It was possible to document the changes in the concentration profiles of both free ionophores and ionic species in some of the membranes. There is no evidence of proton hopping between the ionophores.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19930760124
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  • 5
    Electronic Resource
    Electronic Resource
    Capillary gas chromatography/mass spectrometry of cholesteryl esters with negative ammonia chemical ionization (1987)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 14 (1987), S. 131-140 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Mixtures of both synthetic and naturally occurring (human plasma) cholesteryl esters have been examined by capillary gas chromatography/mass spectrometry (GC/MS). A magnetic sector mass spectrometer was used and a variety of ionization modes were assessed with a view to obtaining structural information on intact cholesteryl esters. By employing ammonia as reagent gas, with negative ion scanning, spectra were produced from which the nature of steryl and fatty acyl moieties could be readily deduced. Analyses were performed at an ion source temperature of 300°C in order to maintain the integrity of the gas chromatographic profile. The technique described is of general use for the GC/MS analysis of steryl esters, particularly in conjunction with magnetic sector instruments.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200140307
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  • 6
    Electronic Resource
    Electronic Resource
    Nitroxide mediated free radical polymerization process - autopolymerization (1995)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 8 (1995), S. 301-305 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The autopolymerization of styrene in the presence of TEMPO (2,2,6,6-tetramethyl-1-piperidinyloxy free radical), with and without organic acids, such as benzoic acid and camphorsulfonic acid, was studied. Broad polydispersities are obtained in the absence of acid, whereas narrower polydispersities are obtained in their presence. The significance of these results for the synthesis of narrow polydispersity polystyrene by the TEMPO-mediated living polymerization process is discussed.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610080413
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  • 7
    Electronic Resource
    Electronic Resource
    The determination of sequence information in homologously related proteins by mass spectrometry (1974)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 1 (1974), S. 269-273 
    Details
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: An azurin, a small respiratory copper protein from the bacterium Pseudomonas fluorescens biotype G, has been studied by mass spectrometry to determine sequence information. The study of homologously related proteins by mass spectiometry is particularly attractive, since the correct nature of major parts of the deduced sequences can be confirmed by comparison with the sequences of the protein from related organisms. An oxidized tryptohan residue has been identified amongst the products from a cyanogen bromide digest of this wild type azurin. In the same digest, a product is also found to arise from cleavage of the peptide chain at the C-terminal side of the same tryptophan residue. These results are rationalized.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200010411
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  • 8
    Electronic Resource
    Electronic Resource
    High-performance liquid chromatography/mass spectrometry with thermospray lonization of free ecdysteroids (1993)
    New York, NY : Wiley-Blackwell
    Rapid Communications in Mass Spectrometry 7 (1993), S. 477-481 
    Details
    ISSN: 0951-4198
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: High-performance liquid chromatography/mass spectrometry (HPLC/MS) with thermospray ionization has been applied to the analysis of free ecdysteroids (polyhydroxylated steroids that serve as arthropod moulting hormones). Of a range of analytical conditions that were tested, optimum results were obtained by the use of re versed-phase HPLC using a methanol + water mixture containing 0.1 M ammonium acetate. The positive-ion spectra of ecdysteroids showed pseudo-molecular ions, [M + H]+, and fragment ions corresponding to the sequential losses of hydroxyl groups. The [M + H - H2O]+ and [M + H - H2O]+ ions were the most abundant for all the compounds tested. Ecdysteroids bearing a C-20 hydroxyl group (e.g. 20-hydroxyecdysone) showed ions characteristic of cleavage of the side-chain from the steroid nucleus. This mode of fragmentation was much less obvious in the case of ecdysteroids lacking C-20 hydroxylation (e.g. ecdysone). Full-scan mass spectra were readily obtained from 1 μg of free ecdysteroids, while a limit of detection of 5 ng (signal-to-noise ratio 3) was attained in the selected-ion monitoring mode. The application of HPLC/MS to the study of ecdysteroids in biological materials is demonstrated by the analysis of extracts of newly laid eggs of the desert locust (Schistocerca gregaria) and pupae of the cotton leafworm (Spodoptera litoralis).
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/rcm.1290070615
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  • 9
    Electronic Resource
    Electronic Resource
    Detection of nucleotide bases in ancient seeds using gas chromatography/mass spectrometry and gas chromatography/mass spectrometry/mass spectrometry (1994)
    New York, NY : Wiley-Blackwell
    Rapid Communications in Mass Spectrometry 8 (1994), S. 503-508 
    Details
    ISSN: 0951-4198
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: Nucleic acid extracts from 1400-year-old radish seeds recovered from excavations at Qasr Ibrim, Upper Egypt, have been analysed by gas chromatography/mass spectrometry and gas chromatography/mass spectrometry/mass spectrometry. tert-Butyldimethyisilyl derivatives of the purine and pyrimidine bases were prepared, after treatment of the nucleic acid extracts with concentrated formic acid. Under electron ionization these derivatives yield prominent [M-57]+ ions that were found to be of value for use in analyses employing selected-ion monitoring and product-ion studies. These two techniques were used in the sensitive and selective detection of nucieotide bases in crude extracts of ancient seeds. The results obtained were supported by complementary analyses of hydrolysates of ancient nucleic acids and authentic bases by means of retention time and spectral comparisons. This work demonstrates for the first time that mass spectrometry can be used in the direct chemical examination of nucleotide bases in ancient materials. This analytical approach is currently being used to address questions regarding the possible chemical (diagenetic) changes occurring in the nucleic acids of ancient biological material.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/rcm.1290080702
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  • 10
    Electronic Resource
    Electronic Resource
    A novel inexpensive device for the electrochemical generation of metallic emitters for field desorption (1977)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 4 (1977), S. 52-54 
    Details
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Details for the construction of a novel, inexpensive device for the electrochemical generation of metallic emitters for field desorption mass spectrometry are described. Use of the device for the generation of cobalt and nickel emitters is demonstrated.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200040107
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