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  • 1
    Electronic Resource
    Electronic Resource
    Dihydromatricariate-based triglycerides, glyceride ethers, and waxes in the australian soldier beetle,Chauliognathus lugubris (Coleoptera: Cantharidae) (1988)
    Springer
    Journal of chemical ecology 14 (1988), S. 411-423 
    Details
    ISSN: 1573-1561
    Keywords: Dihydromatricaria acid ; triglyceride ; (Z)-dec-8-ene-4,6-diynoic acid ; glyceride ethers ; waxes ; antifeedant ; Chauliognathus lugubris ; Coleoptera ; Cantharidae ; accessory glands ; defense
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The soldier beetleChauliognathus lugubris is shown to contain triglycerides and glyceride ethers of 8-dihydromatricaria acid, and waxes of the C12 homolog, of this acid, as well as the previously reported free acid. The triglycerides contain one, two, or three dihydromatricariate moieties, with any remaining positions esterified with normal fatty acids. The glyceride ethers were monostearyl ethers of glycerol esterified with dihydromatricaria acid and oleic or linoleic acid. The waxes, which also include a dihydromatricaria chromophore in the alcohol moiety, occur only in the females and are present in paired accessory glands in the abdomen. The ethers are restricted to females and appear to be associated with developing eggs. The triglycerides are much more abundant in females than males. Triglycerides, glyceride ethers, and waxes represent about 95% of the dihydromatricariate moiety (average, ca. 590 μg) in females with free acid the remainder; in males free acid is present to over 50% (ca. 22 μg) and the remainder is triglyceride (ca. 15 μg). Larvae contain mainly tridihydromatricariate-substituted triglyceride and a smaller quantity of the free acid.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01013893
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  • 2
    Electronic Resource
    Electronic Resource
    Comparison of electrospray ionization and plasma desorption mass spectra of peptides and proteins (1990)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 19 (1990), S. 286-294 
    Details
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The electrospray ionization (ESI) and plasma desorption (PD) mass spectra of over 20 peptides and proteins, with molecular weights (Mr) ranging between 1182 and 143000, have been directly compared. Both techniques produced molecular ions for the majority of materials studied; however, neither approach proved to be universally applicable. PD failed for a number of proteins that were successfully analyzed by ESI, including some of very high Mr. On the other hand, ESI failed for proteins that apparently could not acquire a sufficient number of positive charges to allow transmission through the quadrupole mass filter. A non-covalently bound adduct, ribonuclease S, did not survive either method intact and a simple glycoprotein, ribonuclease B, did not yield the expected molecular ion with either approach. The mass measurement accuracy of quadrupole ESI is five to tenfold better than obtained with a commercial time-of-flight PD mass spectrometer. Furthermore, ESI's superior mass resolution (with quadrupole mass spectrometers) will prove to be particularly helpful for the characterization of mixtures of closely related materials. Sensitivity was only compared qualitatively but is highly compound dependent with both techniques. In favorable cases, ESI spectra can be obtained on low femtomolar quantities of proteins while PD typically requires several hundred femtomoles to high picomoles, depending on a number of factors including Mr.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200190503
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  • 3
    Electronic Resource
    Electronic Resource
    Plasma-desorption mass spectrometry of intact enzymes and proenzymes (1989)
    New York, NY : Wiley-Blackwell
    Rapid Communications in Mass Spectrometry 3 (1989), S. 323-328 
    Details
    ISSN: 0951-4198
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: The plasma desorption (PD) mass spectra of several enzymes and proenzymes are reported. Chymotrypsin and chymotrypsinogen both yield usable PD mass spectra; however, the single-chain chymotrypsinogen exhibits better sensitivity and less fragmentation than the multi-chain chymotrypsin. Porcine pepsinogen contains 11 more basic residues (lysine and arginine) than porcine pepsin, but this does not lead to an increase in positive ion response. In fact, the additional basic residues may hinder response by increasing the strength of the interaction between the protein and the nitrocellulose surface. A series of subtilisins showed comparable PD mass spectrometric, response despite the fact that they differ considerably in primary sequence. Finally, PD mass spectrometry was used to correct the previously reported mass of a heat-stable protease, a value that we found to be in error by almost 5000 Da.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/rcm.1290030914
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  • 4
    Electronic Resource
    Electronic Resource
    Capillary-zone electrophoresis with fraction collection for desorption mass spectrometry (1990)
    New York, NY : Wiley-Blackwell
    Rapid Communications in Mass Spectrometry 4 (1990), S. 24-29 
    Details
    ISSN: 0951-4198
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: A simple method for off-line coupling of desorption mass spectrometry and capillary-zone electrophoresis (CZE) is described. Use of a “porous glass joint”, near the cathodic end of the CZE column, facilitates fraction collection in a manner similar to that used with liquid chromatography. This method allows independent optimization of both the CZE and mass spectrometry parts of the experiment. It is directly applicable to a number of desorption mass spectrometry methods (including plasma desorption (PD) and UV laser desorption (LD)). In the present study, PD mass spectrometry was used for eluant characterization. The fraction collection procedure is described, as is mass transfer through the porous glass joint. Detection limits are discussed and the approach is illustrated by analysis of a simple mixture of bradykinin derivatives. Finally, a brief comparison to current on-line CZE/mass spectrometric methods is presented.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/rcm.1290040108
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  • 5
    Electronic Resource
    Electronic Resource
    The effects of gas-phase basicity and surface activity on the formation of fast-atom bombardment mass spectraThis work is dedicated to the memory of David E. Chapman. (1989)
    New York, NY : Wiley-Blackwell
    Rapid Communications in Mass Spectrometry 3 (1989), S. 46-50 
    Details
    ISSN: 0951-4198
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/rcm.1290030212
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  • 6
    Electronic Resource
    Electronic Resource
    Valence-change in the mass spectra of metal complexes (1972)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 6 (1972), S. 931-937 
    Details
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A review article is presented relating to the concept of valence-change in the mass spectra of metal-containing compounds. It is found that the modes of ion dissociation in these spectra are markedly dependent on the oxidation states normally assumed by the metal concerned and it is postulated that electron-transfer may be possible between the complexed metal atom and its ligands in the ion, such that the odd- or even-electron character of the ion is inter-changeable. Ion reactions such as the consecutive loss of two radicals are normally of low probability in the mass spectra of organic compounds, but are often observed in the mass spectra of metal-containing compounds and can be rationalized in terms of the valence-change concept. Convincing evidence for valence-change in some spectra is provided by the occurrence of reactions leading to the bare metal ion, or to the loss of neutral fragments containing the metal atom in a lower oxidation state than in the precursor molecule. Further applications of the concept may be found in the rationalization of the mass spectra of inorganic and organometallic compounds.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/oms.1210060814
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  • 7
    Electronic Resource
    Electronic Resource
    Chemical ionisation mass spectra of explosives (1974)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 9 (1974), S. 359-364 
    Details
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The chemical ionisation mass spectra of a number of representative explosives have been obtained using hydrogen as reagent gas. Fragmentation modes of the protonated molecular ions tend to be simple although some rearrangements have been noted. Loss of a radical from an even electron parent ion has been observed. The use of ‘ghost spectra’ for confirmation of the molecular weight of the sample is stressed: these consist of ions of low abundance resulting from reactions between sample ions and sample molecules. Labelling studies were carried out using deuterium as reagent gas.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/oms.1210090317
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  • 8
    Electronic Resource
    Electronic Resource
    The mass spectra of metal complexes of dibenzoylmethane (1968)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 1 (1968), S. 115-126 
    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 a series of metal complexes of dibenzoylmethane have been rationalized. The paths of novel rearrangement reactions involving both hydrogen and oxygen migration may differ according to the type of metal atom in the complex. Further examples are proposed of the effect of metal valency changes in ion reactions.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/oms.1210010111
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  • 9
    Electronic Resource
    Electronic Resource
    Loss of CH2O and H2O by stepwise mechanisms in mass spectrometry (1971)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 5 (1971), S. 1391-1397 
    Details
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Experimental evidence demonstrating reversible hydrogen transfer between specific positions in the molecular ions of anisole and o-toluic acid suggests stepwise mechanisms for the loss of CH2O and H2O, respectively. Added support for a stepwise mechanism for the loss of CH2O is found in the mass spectra of pyridine and quinoline analogues.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/oms.1210051206
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  • 10
    Electronic Resource
    Electronic Resource
    Hydrogen randomization and the loss of CH3N in the mass spectra of 2-dimethylaminopyridines (1976)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 11 (1976), S. 848-856 
    Details
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The electron impact mass spectra of some deuterium labelled 2-dimethylaminopyridines are consistent with hydrogen randomization within the dimethylamino group prior to the loss of the elements of methylenimine.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/oms.1210110810
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