ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
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
    An assay for 2-amino-3,8-dimethylimidazo[4,5-ƒ]-quinoxaline and 2-amino-3,4,8-trimethylimidazo-[4,5-ƒ]quinoxaline in fried beef using capillary column gas chromatography electron capture negative Ion chemical ionization mass spectrometry (1988)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 16 (1988), S. 221-224 
    Details
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A gas chromatographic/mass spectormetric assay has been developed for the simultaneous measurement of 2-amino-3,8-dimethylimidazo[4,5-ƒ]quinoxaline (MeIQx) and 2-amino-3,4,8-trimethylimidazo[4,5-ƒ]quinoxaline (DiMeIQx) in fried beef. The method employs capillary column gas chromatography, electron capture negative ion chemical ionization mass spectrometry and a stable isotope labelled analogue of MeIQx as common internal standard. Two patties of lean minced beef which had been cooked separately were analysed and found to contain both compounds (patty 1:2.4 ng MeIQx g-1 meat, 1.2 ng DiMeIQx g-1 meat; patty 2: 1.3 ng MeIQx g-1 meat, 0.5 ng DiMeIQx g-1 meat). Neither compound was present in the meat prior to cooking.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200160140
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Bistrifluoromethylaryl derivatives for drug analysis by gas chromatography electron capture negative ion chemical ionization mass spectrometry. Application to the measurement of (N-dicyclopropylmethyl)amino-2-oxazoline in plasma (1985)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 12 (1985), S. 230-237 
    Details
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A gas chromatographic mass spectrometric assay for (N-dicyclopropylmethyl)amino-2-oxazoline in plasma with a detection limit of 0.1 ng ml-1 was required. Various fluoroaryl derivatives of this compound (code name S3341) were synthesized and their positive ion chemical ionization and electron capture negative ion chemical ionization mass spectra recorded. While fluorobenzyl derivatives of S3341 could be made by heating with the requisite benzyl bromide and diisopropylethylamine in acetonitrile, initial efforts to synthesize corresponding fluorobenzoyl derivatives using a benzoyl chloride in dry ethyl acetate at 60 °C were unsuccessful. Mass spectral data indicated that only a fragment of the oxazoline ring was retained in the reaction product and that an N-(2-chloroethyl)benzamide was formed. However, when diisopropylethylamine was included in the reaction mixture, a benzoyl derivative of the complete molecule was obtained. The mechanisms of these reactions are discussed. The negative ion mass spectrum of the 3,5-bistrifluoromethylbenzoyl derivative of S3341 has a base peak at m/z 420 (the molecular ion) and, when this ion is specifically monitored, an amount of derivative equivalent to 1 pg of S3341 can be detected. This allowed the development of an assay for S3341 in plasma with a precision of 9% (SD) at 0.2 ng ml-1 and a lower limit for quantitative determination of 0.1 ng ml-1.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200120509
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Temperature dependence of NMR secondary references for D2O and (CD3)2SO solutions (1988)
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 26 (1988), S. 523-525 
    Details
    ISSN: 0749-1581
    Keywords: 1H NMR secondary references ; 13C NMR secondary references ; Temperature dependence ; D2O solutions ; (CD3)2SO solutions ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Chemical shifts of secondary references for D2O and (CD3)2SO solutions were measured as a function of temperature. The 1H and 13C chemical shifts of dioxane, sodium 4,4-dimethyl-4-silapentanesulphonate, HOD, tetramethylammonium chloride and sodium 3-(trimethylsilyl)propionate-d4 in D2O solution were measured relative to external TMS and the chemical shifts of (CD3)2SO and H2O were measured in (CD3)2SO solution relative to internal TMS. For accurate comparison of chemical shifts it is necessary to take into account the sample temperature and, therefore, the temperature dependences of 1H and 13C chemical shifts of a number of secondary references have been determined accurately and fitted to a parabola or straight line, as appropriate.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrc.1260260617
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    1H and 13C NMR assignment of maltitol by a combination of 2D NMR and H/D isotope effects on nuclear shielding (1988)
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 26 (1988), S. 425-429 
    Details
    ISSN: 0749-1581
    Keywords: Maltitol ; 13C NMR assignment ; 2D-INADEQUATE ; SIMPLE NMR ; DIS NMR ; 1H NMR assignment ; 1H-13C COSY NMR ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Maltitol was assigned unequivocally without any need for reference to model compounds by a combination of 2D, SIMPLE (secondary isotope multiplets of partially labelled entities) and DIS (differential isotope shift) NMR techniques. The combination of these three techniques is very powerful for the assignment of molecules with many exchangeable hydrogen atoms, such as carbohydrates. In the case of maltitol a complete 13C NMR assignment was achieved in three solvents [H2O, D2O and (CD3)2SO] using three experiments. A 1H-13C 2D correlation experiment allowed the 1H NMR spectrum to be assigned unequivocally for the first time.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrc.1260260514
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...