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  • Analytical Chemistry and Spectroscopy  (12)
  • 1
    Digitale Medien
    Digitale Medien
    Electrospray mass spectrometry on a magnetic sector instrument applied to heteropolyacids (1994)
    New York, NY : Wiley-Blackwell
    Rapid Communications in Mass Spectrometry 8 (1994), S. 692-694 
    Details
    ISSN: 0951-4198
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Physik
    Notizen: Electrospray mass spectrometry has been applied to ionic inorganic systems such as heteropolyacids in methanol + water (1/1) or acetonitrile + water (1/1) solutions. Negative-ion mass spectra were obtained on four different heteropolyacids. Heteropolymolybdates H3PMo12O40 and H4PMo11VO40 and heteropolytungstates H3PW12O40 and H4SiW12O40 gave ions with different charges. H3PMo12O40 gave ions of m/z 1822, 912 and 608 which correspond respectively to [PMo12O403- + 2H+], [PMo12O403- + H+]2- and [PMo12O40]3- ions. Resolution of 1:2200 has demonstrated the charge of each ion acquired. Furthermore, the isotope distribution of the observed ions was in good agreement with theory. Thus, electrospray mass spectrometry has become a powerful soft ionization technique for the analysis of such ionic compounds, provided they are soluble and stable in the solvent system used.
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/rcm.1290080905
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  • 2
    Digitale Medien
    Digitale Medien
    A new method for the determination of iron oxidation states by resonant and non-resonant ionization mass spectrometry (1995)
    New York, NY : Wiley-Blackwell
    Rapid Communications in Mass Spectrometry 9 (1995), S. 225-229 
    Details
    ISSN: 0951-4198
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Physik
    Notizen: Different compositions of micrometric particles of powdered iron oxides (Fe1-xO, Fe3O4 and Fe2O3) are examined by time-of-flight laser microprobe mass spectrometry. The positive-ion cluster distributions show a strong correlation with the stoichiometry of iron in the oxide. This correlation is more striking when the resonant process of iron at 293.7 nm is used. The bond dissociation energy of Fe--O in the bulk Fe1-xO also affects the intensity distributions. It is very important to study and to identify the iron oxides because they could play a role in the toxicity of certain molecules which could be removed on the oxides.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/rcm.1290090310
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  • 3
    Digitale Medien
    Digitale Medien
    Laser microprobe fourier transform mass spectrometry. Preliminary results for feasibility and evaluation (1988)
    New York, NY : Wiley-Blackwell
    Rapid Communications in Mass Spectrometry 2 (1988), S. 146-150 
    Details
    ISSN: 0951-4198
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Physik
    Notizen: The feasibility is reported of coupling a laser microprobe sampling system with a Fourier transform mass spectrometer (FTMS) for surface characterization. Analysis of an integrated circuit chip demonstrates capabilities for focusing the laser on a selected spot on a sample surface. Analysis of a model glass sample for which high resolution is required to separate metal ions from metal oxide ions emphasizes the advantages of coupling such a sampling system to an FTMS instrument.
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/rcm.1290020708
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  • 4
    Digitale Medien
    Digitale Medien
    Laser-desorption Fourier-transform mass spectrometry of triazines adsorbed on solid-phase extraction membranesContribution from the 2nd European FTMS Workshop, Antwerp, Belgium, September 1993. (1994)
    New York, NY : Wiley-Blackwell
    Rapid Communications in Mass Spectrometry 8 (1994), S. 22-25 
    Details
    ISSN: 0951-4198
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Physik
    Notizen: Until the present, analysis of aqueous solutions of atrazine has been conducted using a combination of liquid chromatography or gas chromatography with mass spectrometry, after a preconcentration step. We explore herein a new approach for studying support-phase-extracted atrazine and hydroxyatrazine samples. Solid-phase extraction membranes are inserted directly into the cell of a Fourier-transform mass spectrometer for analysis after laser ionization. It appears that atrazine and its metabolite have very different ionization processes. In the case of hydroxyatrazine, the [M + H]+ ion signal can be correlated to the concentration of the extracted solution. These encouraging results might open the route to a quantification method.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/rcm.1290080105
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  • 5
    Digitale Medien
    Digitale Medien
    Etude par RMN de la Structure des Cyano-2 Alcoyl-2 Norbornenes-5 (1970)
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 2 (1970), S. 71-78 
    Details
    ISSN: 0030-4921
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: Interpretation of the NMR spectra of the isomeric 2-cyano-2-alkyl-5-norbornenes allowed the assignment of their respective structures. In the case of the 2-cyano-2-methyl-5-norbornene the structure assignment was confirmed by chemical synthesis (alkaline hydrolysis and iodo-lactonisation).
    Notizen: L'attribution de structure des deux isomères cyano-2 alcoyl-2 norbornène-5 est possible grǎce aux données de la RMN. Une interprétation des spectres de ces dérivés bicycliques set donnée. Dans le cas des cyano-2 méthyl-2 norbornènes-5 une confirmation de structure a pu ětre donnée par voie chimique (hydrolyse basique et iodolactonisation).
    Zusätzliches Material: 2 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/mrc.1270020109
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  • 6
    Digitale Medien
    Digitale Medien
    Etude du couplage 2J(N15—H) en série hétérocyclique. Application à la détermination des constantes d'équilibres prototropiques rapides (1974)
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 6 (1974), S. 224-225 
    Details
    ISSN: 0030-4921
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: The fast tautomeric equilibrium of (N15)-4-phenylisoxazolin-5-one (2) has been investigated by a study of 2J(N15—H3) coupling. Comparison of the observed values for 2 and for the two fixed forms (N15)-2-methyl-4-phenylisoxazolin-5-one (3) and (N15)-4-phenyl-5-methoxyisoxazol (4) indicates a considerable amount of enolic type structure for 2 in basic media.
    Notizen: La comparasion des constantes de couplage 2J(N15—H3) présentées par la (N15)-4-phénylisoxazoline-5-one (2) et par deux de ses formes fixes, la (N15)-2-méthyl-4-phénylisoxazoline-5-one (3) et le (N15)-4-phényl-5-méthoxyisoxazole (4), indique une participation élevée de structure énolique (et/ou ionique) dans les milieux basiques.
    Zusätzliches Material: 1 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/mrc.1270060408
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  • 7
    Digitale Medien
    Digitale Medien
    Application of low energy CID in the determination of structures of [M - halogen]+ ions obtained from diethyl halosuccinates under electron impact (1987)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 22 (1987), S. 61-63 
    Details
    ISSN: 0030-493X
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Low energy collision induced dissociation (CID) spectra indicate that m/z 173 ions formed by the loss of a halogen atom from diethyl chloro- and bromo-succinate under electron impact are mixtures of O-protonated diethyl maleate (〉90%) and fumarate (〈10 %). Hydrogen migration precedes the C-halogen bond cleavage in these cases. The low energy CID spectrum of the m/z 173 [M—I]+ ion obtained from diethyl iodosuccinate shows that only a small fraction of the [M—I]+ ions are the O-protonated species formed by hydrogen migration. The results of this study demonstrate the potential of low energy CID in the determination of structure (including configuration) of gas phase ions.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/oms.1210220202
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  • 8
    Digitale Medien
    Digitale Medien
    Aluminium-27 MAS NMR of Al2Ge2O7 and LaAlGe2O7: Two pentacoordinated aluminium environments (1990)
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 28 (1990), S. S82 
    Details
    ISSN: 0749-1581
    Schlagwort(e): 27 Al MAS NMR ; Quadruopolar interaction parameters ; Isotropic chemical shfits ; Spectral simulation ; Al2Ge2O7 ; LaAlGe2O7 ; Pentacoordinated aluminium environment ; Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Characterization by 27Al MAS NMR of two pentacoordinated environments of aluminium has been carried out in different fields and at different spinning speeds for Al2Ge2O7 and LaAlGe2O7. Complete simulations of the spectra have been performed, including computation of the individual shape and intensity of each spinning side band, which lead to the determination of both the quadrupolar interaction parameters and isotropic chemical shifts, and enable the detection of impurities in the material. The parameters determined are: .
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/mrc.1260281314
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  • 9
    Digitale Medien
    Digitale Medien
    13C and proton nuclear magnetic resonance spectra of trans-[arylbromobis(triethyl phosphine)palladium(II)] and related compounds. The π-donor ability of the Ni(PEt3)2X, Pd(PEt3)2X and Pt(PEt3)2X groups (1986)
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 24 (1986), S. 243-246 
    Details
    ISSN: 0749-1581
    Schlagwort(e): 13C NMR ; 1H NMR ; Ni-Pd-Pt series ; Ni-Pd-Pt substituent effects ; Ni/Pd/Pt-induced paramagnetic shifts ; M(PEt3)2X substituents ; Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: 13C and proton NMR spectra of several arylpalladium and some arylnickel and arylplatinum complexes have been compared. The Ni(PEt3)2X and Pd(PEt3)2X substituents induce a paramagnetic shift of Cipso (of the phenyl ring) which is much larger than that induced by Pt(PEt3)2X. However, there are no significant differences along the Ni/Pd/Pt series for the ortho, meta and para positions. For the six compounds of general formula trans-[ArPdBr(PEt3)2] reported here, the mean Δ(δ)C values induced on the ArH by the introduction of the PdBr(PEt3)2 substituent are found to be 26.9 (Cipso), 7.2 (Cortho), -1.1 (Cmeta), -5.5 (Cpara), -0.03 (Hortho), -0.28 (Hmeta) and -0.38 ppm (Hpara).
    Zusätzliches Material: 4 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/mrc.1260240311
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  • 10
    Digitale Medien
    Digitale Medien
    Conformational changes of amino acids monitored by deuterium nuclear relaxation rate (1986)
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 24 (1986), S. 284-286 
    Details
    ISSN: 0749-1581
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: As an extension of previous work on simple amino acids, deuterium nuclear relaxation rates were used to study the molecular dynamics of γ-2,2-[2H2]aminobutyric acid, d,l-2-[2H1]glutamic acid and d,l-2-[2H1]lysine, and also model compounds 2,2,2-[2H3]acetic acid and 1,1-[2H2]butylamine. This study was carried out in aqueous solution in the pH range ca 0-14. From the observed rotational correlation times and solution viscosities, molecular volumes of various ionic forms were calculated using the Gierer and Wirtz model. The results obtained are in good agreement with conformational changes expected in the pH range investigated.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/mrc.1260240403
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