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  • Air Transportation and Safety  (11)
  • Analytical Chemistry and Spectroscopy  (11)
  • 1
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 5 (1978), S. 515-517 
    ISSN: 0306-042X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Using gas chromatography mass spectrometry following derivatization (N-trifluoroacetylation), 1-N-acetylspermidine was found to occur in normal human serum at a level of approximately 0.008-0.05 nmol ml-1, i.e. about two orders of magnitude lower than the corresponding spermidine level. No evidence for the occurrence in serum of the isomeric 8-N-acetylspermidine was found. Mass spectra of authentic samples of trifluoroactylated 1-N- and 8-N-acetylspermidine are presented.
    Additional Material: 1 Ill.
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  • 2
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 26 (1991), S. 723-726 
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 5 Ill.
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  • 3
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 28 (1993), S. 83-91 
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The recently synthesized ammonium dinitramide (ADN) is an ionic compound containing the ammonium ion and a new oxide of nitrogen, the dinitramide anion (O2N—N—NO2-). ADN has been investigated using high-energy xenon atoms to sputter ions directly from the surface of the neat crystalline solid. Tandem mass spectrometric techniques were used to study dissociation pathways and products of the sputtered ions. Among the sputtered ionic products were NH4+, NO+, NO2-, N2O2-, N2O2-·, N3O4- and an unexpected high abundance of NO3-. Tandem mass spectra of the dinitramide anion reveal the uncommon situation where a product ion (NO3-) is formed in high relative abundance from metastable parent ions but is formed in very low relative abundance from collisionally activated parent ions. It is proposed that the nitrate anion is formed in the gas phase by a rate-determining isomerization of the dinitramide anion that proceeds through a four-centered transition state. The formation of the strong gas-phase acid, dinitraminic acid (HN3O4), the conjugate acid of the dinitramide anion, was observed to occur by dissociation of protonated ADN and by dissociation of ADN aggregate ions with the general formula [NH4(N(NO2)2)n] NH4+, where n = 1-30.
    Additional Material: 13 Ill.
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  • 4
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 29 (1994), S. 247-252 
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Fast atom bombardment (FAB), FAB mass-analysed ion kinetic energy (FAB MIKE) and collision-activated dissociation (FAB CAD-MIKE) mass spectra were obtained for two series of unsaturated anomeric aryl C-glycosides. These tandem mass spectrometric techniques allowed the differentiation of the anomers by analysing either the [M + H]+ ion or the [M + met]+ ion (met=Li, Na).
    Additional Material: 6 Ill.
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  • 5
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 15 (1988), S. 399-402 
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A fast atom bombardment/collisional activation/linked-scan at constant B/E (tandern mass spectrometric) method is described which can distinguish between α- and β-aspartyl and α- and μ-glutamyl underivatized peptides. The method is based upon differences in loss of CO from aspartyl or glutamyl B-fragment ions (IB) in these isomers which are rationalized from the stability of the resultant A-fragment ions (IA). It was observed that the ratio of IB:IA which was used in this determination was dependent upon the collision cell pressure. The higher the collision cell pressure, the larger the difference between the IB: IA ratios for these linkages.
    Additional Material: 4 Ill.
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  • 6
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A capillary gas chromatographic/mass spectrometric method for the determination of tebufelone, a new anti-inflammatory drug, in plasma and rat paw tissue is described. Trideuteriated tubufelone was employed as an internal standard and the drug quantified by selected ion monitoring using a mass-selective detector following positive electron ionization (70 eV). Tebufelone was recovered from plasma (〉93%) and pulverized paw tissue (〉88%) by ethereal extraction. Standard curves were linear between 5 ng ml-1 and 5 μg ml-1 with a detection limit (S/N = 2) of 2 ng ml-1. The coefficient of variation for successive injections of standards (200 ng ml-1) or samples (10-1500 ng ml-1) was 7.3% and 8.5%, respectively.
    Additional Material: 6 Ill.
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  • 7
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 4 (1977), S. 146-151 
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Quantitative analyses of subnanomole quantities of the polyamines putrescine, cadaverine, spermidine and spermine by the gas chromatography mass spectrometry technique of selected ion monitoring are complicated by effects of the chromatographic column. These effects include sample retention by the column and chromatographic band broadening, and are sufficiently serious that spermine (as the trifluoroacetylated derivative) was not detectable at levels below 50 picomoles. Because the chromatographic behaviors of the four polyamines vary, quantiative analysis using a single internal standard is not feasible. The deuterated polyamine analogs, putrescine-2H4, cadaverine-2H4, spermidine-2H6 and spermine-2H8, have been synthesized and used to accomplish quantiative analyses of the corresponding isotopically natural abundance polyamines to the one picomole level. This enhancement in analytical sensitivity is accomplished by use of large excesses (≥100 picomoles) of the deuterated analogs to improve chromatographic band profiles. The use of such large molar excesses of deuterated analogs for selected ion monitoring analyses is possible because their electron impact spectra exhibit high mass ions {[M-F3C]+, [M-F3CCO]+} which possess ≥ 4 deuterium atoms and have intensity ratios (I2H(max): IH) of 500 or greater.
    Additional Material: 5 Ill.
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  • 8
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Analysis by field desorption mass spectrometry of reaction product mixtures produced by treatment of peptides with methanol and hydrogen chloride augments significantly structural data derived by direct field desorption mass spectrometry analysis of the peptides. Analyses of data obtained by three peptides, β-Ala-HisOH, p-Glu-Ser-GlyOH and Glu-Ser-Gly-AspOH are used for illustration. Data from field desorption mass spectrometry of peptide methylation-methanolysis product mixtures are used to (a) distinguish [M]+ from [M + H]+ in peptide field desorption mass spectrometry spectra, (b) ascertain the number of carboxyl groups present in a peptide, (c) identify a pyro-glutamyl N-terminus and (d) derive peptide sequence information. Definitive assignments of ion relationships are facilitated by use of methanol and deuteromethanol in paired experiments.
    Additional Material: 1 Tab.
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  • 9
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 4 (1977), S. 275-279 
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A new metabolite of 5,5-diphenylhydantoin has been found in human urine and in rat bile. This new metabolite arises by direct glucuronidation of 5,5-diphenylhydantoin (i.e. no prior aryl hydroxylation occurs) and is characterized as the N-3 glucuronide. This structure assignment is based on (a) study of mass spectra of permethyl, perdeuteriomethyl, N-methyl-per-O-deuteriomethyl and deuteriomethyl ester permethyl derivatives and (b) comparison of the reactions of the new glucuronide metabolite and 5,5-diphenyl-3-methylhydantoin with diazomethane. Prominent ions at m/e 322 and 378 in the mass spectrum of the permethylated derivative of the glucuronide metabolite arise via retro Diels-Alder reactions of the glycone ring.
    Additional Material: 4 Ill.
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  • 10
    ISSN: 0935-6304
    Keywords: High performance liquid chromatography ; Resolution of enantiomers ; Chiral stationary phase ; 1-Phenyl-2-aminopropane, amide derivatives ; Amphetamine derivatives ; Reversal of elution order ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Enantiomeric amide derivatives of (S)- and (R)-1-phenyl-2-aminopropane (dextro- and levoamphetamine, respectively) were resolved by high performance liquid chromatography on commercially available ionically and covalently bonded chiral stationary phases ((R)-N-(3,5-dinitrobenzoyl)phenylglycine). Ten enantiomeric amide pairs were synthesized and chromatographed on the columns by using a mobile phase of hexane-isopropanol (97 : 3), a flow rate of 2 ml/min, and a column temperature of 20°C. The (R)-isomer of all 10 amides eluted first on the covalent column as did the (R)-isomer of nine derivatives on the ionic column. however, the 3,5-dinitrobenzoyl amide of (S)- amphetamine eluted before the (R)-isomer on the ionic column. This reversal in enantiomeric elution order reveals the complexity of the interactions occurring on these columns and emphasizes the hazards of relying on observed elution order as an a priori indication of absolute configuration.
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