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  • 1
    ISSN: 0951-4198
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: A new mass spectrometry technique using an inductively coupled plasma (ICP) ionization source and an ion-trap mass spectrometer (ITMS) detector is described and evaluated for elemental and isotopic analysis. Initial results obtained with the ICP-ITMS technique include sub-ppb detection of bare ions for, most elements, complete destruction of typical polyatomic matrix ions (e.g., CIO+, ArO+, and ArCl+), and effective neutralization of strong Ar+ ion currents. The latter effects allow observation of clearer mass spectra at m/z 〈 80 and potentially improved detection of ‘problem’ elements in ICP-MS (e.g., K, Ca, V, Fe, As, and Se). Formation of poly-oxide and -hydroxide ions of metals with high oxide bond strengths were observed and require system modifications to alleviate.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Mass Spectrometry Reviews 13 (1994), S. 287-339 
    ISSN: 0277-7037
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Additional Material: 28 Ill.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 22 (1987), S. 224-228 
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: An abundant loss of hydroxyl in decompositions of ortho-substituted nitroarene cations is commonly observed when the substituent contains one or more labile hydrogen atoms. The major loss of hydroxyl also takes place from many but not all of the corresponding molecular anions. Data are reported for the collisionally activated decompositions of the cations and anions of o-nitrotoiuene, o-nitrophenol and o-nitroaniline. Data for some dinitro ions are also reported. The results can be rationalized on the basis of a greater degree of charge developed at the substituent in the transition state of the anions that leads to a rearranged ion. It is from this structure tint hydroxyl is lost via simple bond cleavage. This can be viewed most simply as a proton transfer from the substituent to the nitro group in the anion as opposed to hydrogen transfer in the analogous step for the cation. The degree to which hydroxyl loss occurs is therefore largely determined by the tendency for hydrogen (cations), or proton (anions), transfer from the substituent to the nitro group.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Microcolumn Separations 7 (1995), S. 461-469 
    ISSN: 1040-7685
    Keywords: mass spectrometry ; on-line capillary electrophoresis ; MS / MS analysis ; sheathless electrospray source ; peptides ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The sensitivity that can be obtained with the quadrupole ion trap for on-line CE analysis using a sheathless electrospray interface and gold-tipped columns is examined. Capillaries of different i.d. are compared in continuous infusion experiments and the effects of sheath solvents on the signal for some peptides and proteins are illustrated. The sheathless CE/ITMS system using 20 μm i.d. columns is shown to provide mid-attomole detection levels for leucine enkephalin in total ion electropherograms under full scan conditions. Good quality MS/MS spectra are also obtained for low femtomole injections of this peptide.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 30 (1995), S. 1222-1229 
    ISSN: 1076-5174
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Tandem mass spectra of a variety of adenine-containing deoxynucleic acid anions obtained using collisional activation in a quadrupole ion trap are described. Data are reported for singly charged mono-, di- and trinucleotide species, and also for multiply charged anions derived from tri-, tetra-, penta- and hexanucleotides. Attention is focused on the first step in the unimolecular decomposition of these species, namely the loss of the nucleobase. Specifically, the competition between the loss of the nucleobase as a neutral versus its loss as an anion is addressed within the context of a proposed proton-bound intermediate consisting of the nucleobase and a phosphodiester linkage. The data are interpreted on the basis of the energy surface involved in the break-up of the proton-bound intermediate, which can explain why the competition between loss of a neutral versus charged base is strongly dependent upon the charge of the parent ion.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 18 (1995), S. 439-442 
    ISSN: 0935-6304
    Keywords: Electrokinetic chromatography (EKC) ; Pseudo-stationary phase ; Electroosmotic flow ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 24 (1989), S. 470-478 
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The scan modes that can be used to obtain daughter ion, parent ion, and constant neutral-loss spectra on hybrid mass spectrometers are derived for instruments with a quadrupole combined with a magnetic and/or electric sector. All combinations of sector/quadrupole and quadrupole/sector instruments are discussed. The advantages or lack thereof of the various scans are presented with respect to operation, resolution and potential artifacts.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 23 (1985), S. 939-944 
    ISSN: 0749-1581
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A key intermediate in porphyrin and corrin biosynthesis is the trisubstituted pyrrole porphobilinogen (PBG). The fate of PBG in the biosynthesis of porphyrins and corrins has been monitored by NMR spectroscopy in vivo and in vitro employing various nuclei. The syntheses of highly tritiated PBG and its immediate precursor 5-aminolevulinic acid (ALA) are reported, together with 3H, 1H and 13C assignments.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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