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  • 1995-1999
  • 1985-1989  (6)
  • Analytical Chemistry and Spectroscopy  (6)
  • 1
    Electronic Resource
    Electronic Resource
    FAB and tandem mass spectrometry for endorphin- and ACTH peptides of molecular weight to 2000 (1988)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 15 (1988), S. 649-657 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Four β-endorphins (β-endorphin 6-17, 2-17, 1-16, and 1-17) and two adrenocorticotropic hormone (ACTH) peptides (ACTH 1-10 and (1-16)-NH2) were studied by using fast atom bombardment coupled with tandem mass spectrometry. The capability to reproduce metastable ion and collisionally activated decomposition spectra on two different commercial sector mass spectrometers in two different laboratories was found to be acceptable (deviations in relative abundance are less than ± 50%). The endorphin peptides fragment metastably or upon collisional activation to give abundant B-series ions as well as Y-series ions, whereas Y-series ions are the principal ionic species produced upon the desorption by fast atom bombardment. The ACTH peptides also fragment to give Y-series ions, but of relatively low abundance compared to those from the endorphins. For both sets of peptides, high-energy collisionally activated decomposition and metastable ion decomposition daughter ion spectra are precise, structurally informative - even for peptides up to m/z 2000 - and complementary to spectra of daughter ions produced by desorption ionization alone.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200151203
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Fast atom bombardment and tandem mass spectrometry for structure determination: Remote site fragmentation of steroid conjugates and bile salts (1988)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 15 (1988), S. 89-98 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A series of 35 steroid conjugates (sulfates and glucuronides) and bile salts were investigated by using fast atom bombardment and tandem mass spectrometry. Collisional activation of the [M - H]- anions of sulfate conjugates and bile salts predominantly yields fragment ions arising by reactions occurring remote from the charge site. These reactions are sometimes sensitive to differences in stereochemistry at positions remote from the charge site and are useful for positional isomer differentiation. On the other hand, collisional activation of the [M - H]- anions of the glucouronide conjugates leads primarily to charge-driven fragementations.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200150206
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Elucidation of some fragmentations of small peptides using sequential mass spectrometry on a hybrid instrument (1989)
    New York, NY : Wiley-Blackwell
    Rapid Communications in Mass Spectrometry 3 (1989), S. 217-221 
    Details
    ISSN: 0951-4198
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: Sequential daughter-ion-scanning analyses of small peptides have been performed using a hybrid tandem instrument of BEqQ configuration. Precursor ions are selected by B and allowed or induced (by high-energy collisional activation) to decompose in the region preceding E. Decoupling of E from the accelerating voltage permits the selection of the first-generation daughter ion whilst retaining appropriate float voltages for the quadrupole assemblies. The daughter ion selected by E is further subjected to low-energy collisional-activation dissociation (CAD) in q and the fragment-ion spectrum is obtained by scanning Q. The sequential daughter-ion-scanning technique has been used to establish that ‘internal’ fragments of the types, (AY′) and (BY′), are formed via initial Y-type cleavage. Fragmentation of a protonated peptide (angiotensin III) by loss of the C-terminal amino acid residue, yielding a (Bn′ + OH) ion, is reported for the first time. This process is analogous to that previously described for metal-cationized peptides.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/rcm.1290030704
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    Paper (German National Licenses)
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  • 4
    Electronic Resource
    Electronic Resource
    Elemental compositions from daughter ion spectra of m1+ and [m1 + 1]+: Some applications of the method (1988)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 23 (1988), S. 712-718 
    Details
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The elemental compositions of ions can be determined in tandem mass spectrometry by comparing the daughter ion spectra of the m1+ and [m1 + 1]+ ions. The method is demonstrated for mass-analyzed ion kinetic energy spectra but is applicable to all types of daughter ion spectra, including complex collisionally activated dissociation spectra. In this work, the method is applied to compounds that produce daughter ions of known elemental compositions, and the errors and limitations are evaluated. Following that test, the procedure is applied to a compound that may produce daughters of more than one possible elemental composition. The method is sometimes useful even if the formula of the parent is not known; that is, the formulae of unknown parent and daughter ions may be found. Locating a specific atom in an isotopically labeled molecule is another capability of the method. The basic equation of the method was generalized and incorporated into a computer program for performing the calculations.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/oms.1210231007
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    Paper (German National Licenses)
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  • 5
    Electronic Resource
    Electronic Resource
    A mass spectral study of stable neutral enols (1986)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 21 (1986), S. 565-569 
    Details
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The high-resolution mass spectra of two stable enol tautomers, 4,6-diethanoyl-1-methyl-5-phenyl-3-cyclohex-ene-1,3-diol (2) and 4-ethanoyl-5-hydroxy-2-(1-hydroxyethylidene)-5-methyl-3-phenylcyclohexanone (3), and the corresponding diketone tautomer, 2,4-diethanoyl-5-hydroxy-5-methyl-3-phenylcyclohexanone (1), are reported. Collisional activation of the molecular ions and major ionic fragments is used to assign decomposition pathways and to compare ion structures. Ionized 1 and 2 do not interconvert by a keto-enol tautomerism, but isomerize to a common intermediate. This isomerization probably involves opening of the cyclohexanone ring and transfer of the enolizable hydrogen, and is followed by elimination of water. The radical cation of 3 does not interconvert with [1]+· and [2]+· Instead, [3]+· dissociates by loss of an acetyl radical and eliminates water via a higher-energy pathway. As a result, the mass spectra of 1 and 2 are similar, whereas the mass spectrum of 3 is unique.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/oms.1210210907
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    Paper (German National Licenses)
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  • 6
    Electronic Resource
    Electronic Resource
    The cycloaddition of the 1,3-butadiene radical cation with acrolein and methyl vinyl ketone (1989)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 24 (1989), S. 637-646 
    Details
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The 1,3-butadiene radical cation reacts with acrolein and methyl vinyl ketone to produce ‘stable’ adducts. The nature of the reaction and the structures of the adducts were investigated by collisional activation decomposition (CAD) combined with tandem mass spectrometry (MS/MS), and also by Fourier transform mass spectrometry. The CAD spectra of gas-phase adducts were compared with those of suitable model compounds. On that basis, it was determined that the 1,3-butadiene radical cation undergoes a cycloaddition with these α,β-unsaturated carbonyl compounds. The butadiene radical cation serves as the ‘ene’, and the acrolein and methyl vinyl ketone react as dienes, forming cycloadducts having 2-ethenyl-2,3-dihydropyran radical cation structures.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/oms.1210240821
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    Paper (German National Licenses)
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