GLORIA

GEOMAR Library Ocean Research Information Access

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    Analytical chemistry 59 (1987), S. 194-197 
    ISSN: 1520-6882
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 2
    ISSN: 1520-6882
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 3
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Rapid Communications in Mass Spectrometry 5 (1991), S. 586-590 
    ISSN: 0951-4198
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: The use 4-hydroxybenzenesulfonic acid as reduction-inhibiting and general purpose matrix in fast-atom bombardment liquid secondary-ion mass spectrometry (FAB/LSIMS) is discussed. Results obtained in a comparative study using the disulfide-bridge containing peptide deaminoarginine-vasopressin and several commonly used matrices indicate that the reduction-inhibitaing efficiency of 4-hydroxybenzenesulfonic acid is comparable to that of 3-nitrobenzyl alcohol while recuction is found to be important in matrices such as thioglycerol and glycerold. Experiments conducted on peptides such as met-enkephalin and bradykinin, nucleosides and other polar compounds reveal that 4-hydroxybenzenesulfonic acid is a good solvent and has physical properties which are similar to those of glycerol. This new matrix material is a radical scavenger, surface active, allows persistent secondary-ion beams and produces a low background signal. The matrix, 4-hydroxy-benzenesulfonic acid, generally yields high quality mass spectra which compare well with those obtained in either glycerol or 3-nitrobenzyl alcohol.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 4
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Rapid Communications in Mass Spectrometry 6 (1992), S. 85-88 
    ISSN: 0951-4198
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: The mass spectral behavior of a series of substituted 2-phenyl-1,3-dioxolanes has been studied by several ionization techniques in order to gain further insight into the basic ionization mechanisms occurring in the fast-atom bombardment mass spectrometry. The results obtained show that in chemical ionization, ions of the type [M+H]+ are predominant while [M—H]+ ions are observed as important species in electron ionization and fast-atom bombardment. Comparison of the gas-phase hydride-ion affinities of thr chemical ionization reagent gases ammonia and isobutane with those of the loquid matrices glycerol and dithiothereitol/dithioerythritol indicates that the predomionant formation of the [M—H]+ ion observed in fast-atom bombardment by hydride abstraction in the gas phase is improbable. Furthermore, comparison of the electron ionization behavior of the cyclic acetals with that observed under fast-atom bombardment suggests that the origin of [M—H]+ in the latter is not related EI gas-phase processes.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 5
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Rapid Communications in Mass Spectrometry 9 (1995), S. 888-894 
    ISSN: 0951-4198
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: The advantages offered by the scanning facility of a multisector hybrid mass spectrometer of E1BE2qQ geometry, with software featuring an ‘experimental design’ function, are used to elucidate the origin of an artefact observed at m/z 290.8 in the linked scan spectrum at constant B/E of the m/z 299 ion of N,N-bissalicylidene 1,2-phenylenediamine, when performed using a forward geometry (EB) instrument. A previously proposed explanation, whereby the artefact peak was thought to originate from a fragmentation in the first field-free region, could not be verified by repeating the scan using an instrument of E1BE2qQ geometry, where E1 and E2 were linked during the scan at constant B/E. Several different scans were performed using an ‘experimental design’ scanning function, which allows analyzers to be scanned and linked by means of user-defined relationships. Thus, a mass-analysed ion kinetic energy (MIKE) (E2) scan, with E1 set to a value of 0.9725E0, revealed a peak at a value of 0.9462E0 which was subsequently determined to be due to an ion with a mass-to-charge ratio of 299, by using the quadrupole mass filter. A recently proposed graphical method, that allows the field values at which the artefact ion is transmitted to be plotted three dimensionally on a cube, illustrates that while the peak will appear in the spectrum obtained using a linked scan at constant B/E using an EB instrument, this will not be the case with an EBE geometry instrument. The EBE arrangement shows that the interference peak at m/z 290.8 appears to be the result of the transition of a higher-mass ion within the first electrostatic sector.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 6
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Rapid Communications in Mass Spectrometry 6 (1992), S. 485-491 
    ISSN: 0951-4198
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: An Approach which allows the determination of the specific effects of experimental parameters on the extent of reduction observed in fast-atom bombardment/liquid-assisted secondary-ion mass spectrometry (FAB/LSIMS) has been developed. The methodology is based on the isolation of the different components-background, reduction extent, and isotopic abundances - which contribute to peak intensities in the molecular-ion cluster. The individual contributions of reduction and background are calculated by an algorithm SRBC (simulated reduction and background calculations) which utilizes a Monte-Carlo method to optimize the values obtained for these variables. This approach has been used to examine the effects of analyte concentration, primary-beam energy and beam density on the extent of reduction in FAB/SIMS experiments. The results obtained indicate that the beam energy has no significant effect on the apparent reduction, as measured by the experimental (A+2)/A isotope peak ratio, while analyte concentration and beam density effects are obseerved. However, background and reduction data generated by SRBC demonstrate that in some cases there is little effect of these parameters on the true reduction of the analyte and that the increase in apparent reduction with the variation in these parameters results mainly from an artefact created by an increase in the background signal at lower concentrations and higher beam densities.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 7
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Rapid Communications in Mass Spectrometry 9 (1995), S. 1310-1314 
    ISSN: 0951-4198
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: The possible presence of artefact peaks in mass-analyzed ion kinetic energy (MIKE) spectra has been recognized when such scans are performed using a two-sector instrument of reverse (BE) configuration. Since the presence of an artefact peak can be misleading when interpreting a spectrum, a new scan is proposed which allows these artefacts to be identified. This scan involves linking and scanning the two electrostatic sectors of an E1BE2 geometry instrument, while maintaining the magnet at the mass selected for the MIKE scan. This selected mass-analyzed ion kinetic energy (SMIKE) scan at E1=E2 results in a spectrum containing only artefact peaks that can be present in the corresponding MIKE spectrum.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 8
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Rapid Communications in Mass Spectrometry 9 (1995), S. 387-396 
    ISSN: 0951-4198
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: The problem of artefact peaks, in spectra obtained from various tandem mass spectrometric scans on instruments of both forward and reverse geometry, is examined. The filtering conditions imposed by additional analyzers are investigated, in order to evaluate the potential of several different triple sector geometries to reduce specific interferences. No previous evaluation of the rejection ability for artefacts of different origins has been presented with respect to the various geometries. In order to gain a better insight into the origin of various artefacts, and to more easily explain their occurrence in certain geometries, a new graphical representation was developed in order to take into account the effects of three analyzer fields. This approach allows different linked scans to be projected within a cube, while also qualitatively proposing an explanation for the presence or absence of artefact peaks. New scans can also be conceived by means of this method, as is the case with a new selected mass ion kinetic energy (SMIKE) scan, which allows artefacts present in MIKE scans performed using reverse geometry instruments to be determined.
    Additional Material: 15 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 9
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 19 (1990), S. 13-26 
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The determination of the amino acid composition and sequence of a peptide, using both conventional and tandem fast atom bombardment mass spectrometry, is presented. First a list of potential empirical formulae is generated using the accurate mass and isotopic peak intensity ratios from the molecular ion cluster. The formulae are mathematically analyzed to ensure that they correspond to linear peptides composed of 19 common amino acids. Then using the ions below m/z 160 Da, which are characteristic of the amino acid content of the peptide, the formulae are decomposed into possible amino acid compositions. From each composition sequences are generated and their predicted fragment ions are compared to ions present in the mass spectrum. A score based on the intensities and the occurrence of consecutive sequence fragments is calculated. Finally sequences with the ten highest scores are retained. Analyses performed on typical peptides with molecular weights below 1500 Da indicate that identification can generally be achieved using this approach.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 10
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 25 (1990), S. 435-437 
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...