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  • Analytical Chemistry and Spectroscopy  (12)
  • 1990-1994  (12)
  • 1
    Electronic Resource
    Electronic Resource
    Electron ionization mass spectrometry of phenylpyridazinylmethanols and phenylpyridazinyl ketonesCounts as 62nd communication on pyridazines; for part 61, see Ref. 1. (1991)
    New York, NY : Wiley-Blackwell
    Rapid Communications in Mass Spectrometry 5 (1991), S. 421-424 
    Details
    ISSN: 0951-4198
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: The mass spectrometric fragmentation behaviour of four monosubstituted pyridazines (phenyl-3- and phenyl-4-pyridazinylmethanol, phenyl-3-pyridazinyl and phenyl-4-pyridazinyl ketone) was investigated. Fragmentation pathways were established by combined interpretation of the data obtained from high resolution measurements and from low-energy collision-activated dissociation mass spectra of the molecular ions as well as of several important fragment ions. A clear differentiation between these 3- and 4-substituted 1,2-diazines is possible for both sets of pyridazines. Only the spectra of the 3-isomers exhibit an abundant [M—H]+ peak, which indicates a cyclization of these ions involving one ring nitrogen atom. Another difference between the two isomeric phenylpyridazinylmethanols is the loss of OH from the molecular ion, as detected for the C-3 substituted compound only. For the phenylpyridazinyl ketones, the loss of CO from the molecular ion, which is only observed with the 3-isomer, permits an unequivocal differentiation.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/rcm.1290050909
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  • 2
    Electronic Resource
    Electronic Resource
    Methodological approach to the characterization of diacylphosphatidyl cholines in rabbit lung lavage fluid by fast-atom bombardment mass spectrometryDedicated to Prof. J. F. K. Huber on the occasion of his 65th birthday. (1990)
    New York, NY : Wiley-Blackwell
    Rapid Communications in Mass Spectrometry 4 (1990), S. 19-23 
    Details
    ISSN: 0951-4198
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: Strong evidence exists that the distribution of phospholipids in the lung is a function of the degree of adult respiratory distress syndrome. The capabilities of positive-ion fast-atom bombardment (FAB) mass spectrometry for the determination of the relative distribution of intact diacylphosphatidylcholine species in lung lavage fluid were investigated. Two different FAB matrices and two different isolation/purification procedures - extraction/thin layer chromatography - high performance liquid chromatography (TLC-HPLC) - have been evaluated. In addition the relative fatty acid composition of the diacylphosphatidylcholines was determined by negative-ion FAB mass spectrometry using the [RCOO]- fragment ion. These results were compared with those obtained by gas chromatographic determination of the fatty acid methylesters.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/rcm.1290040107
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  • 3
    Electronic Resource
    Electronic Resource
    Electron impact ionization mass spectrometry and tandem mass spectrometry of phenylalkylpyridazinesPyridazines, Part 56; for Part 55, sec Ref. 1. (1991)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 26 (1991), S. 595-600 
    Details
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The mass spectrometric fragmentation behaviour of pyridazine and four monosubstituted derivatives containing a pbenylalkyl side-chain (3- and 4-benizylpyridazine, 3- and 4-(2-pbenylethyl)pyridazine) was investigated. In the electron impact ionization mess spectra of the 3-substituted compounds abundant [M - H]+ peaks are observed. This allows a clear distinction between 3- and 4-substituted pyridazines, as the spectra of the latter isomers show only very weak [M - H]+ signals. The stability of [M - H]+ ions derived from 3-alkylpyridazines (deduced from only the very low abundance of further fragment ions) gives strong evidence for a cyclic structure of these ions. One fragmentation pathway typical of the parent pyridazine, the [M - N2] fragmentation, was not detectable with any of the phenylalkylpyridazines investigated. Instead, loss of HCN, H3CN+ and N2H+ was observed. An interesting fragmentation, observed with 3-(2-phenylethyl)pyridazine, is the loss of +CH3 from the molecular ion and also from the [M - H]+ ion.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/oms.1210260611
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  • 4
    Electronic Resource
    Electronic Resource
    A chloroform-resistant, low-molecular-mass matrix for 252Cf-plasma desorption mass spectrometry (1991)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 26 (1991), S. 804-806 
    Details
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/oms.1210260919
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  • 5
    Electronic Resource
    Electronic Resource
    Characterization of synthetic N-acetylcysteine conjugates by positive- and negative-ion 252Cf plasma desorption mass spectrometry (1991)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 26 (1991), S. 1065-1073 
    Details
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: N-Acetylcysteine and nine N-acetylcysteine conjugates of synthetic origin were characterized by positive- and negative-ion plasma desorption mass Spectrometry. For sample preparation the electrospray technique and the nitrocellulose spin deposition technique were applied. The fragmentation of these compounds, which are best seen as S-substituted desaminoglycylcysteine dipeptides, shows a similar behaviour to that of linear peptides. In the positive-ion mass spectra intense protonated molecular ion peaks are observed. In addition, several sequence-specific fragment ions (A+, B+, [Y + 2H]+, Z+), immonium ions (I+) and a diagnostic fragment ion for mercap-turic acids (RM+) are detected. The negative-ion mass spectra exhibit deprotonated molecular ions and in contrast only one fragment ion corresponding to side-chain specific cleavage ([RXS]-) representing the xenobiotic moiety. In the case of a low alkali metal concentration on the target, cluster molecular ions of the [nM + H]+ or [nM - H]- ion type (n = 1-3) are observed. The analysis of an equimolar mixture of eight N-acetylcysteine conjugates shows different quasi-molecular ion yields for the positive- and negative-ion spectra.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/oms.1210261207
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  • 6
    Electronic Resource
    Electronic Resource
    Rapid molecular mass determination of mono-, Di- and triglycerides by 252Cf plasma desorption mass spectrometry using 3-(3-pyridyl)acrylic acid as matrix (1994)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 29 (1994), S. 108-111 
    Details
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/oms.1210290209
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  • 7
    Electronic Resource
    Electronic Resource
    Positive and negative ion 252Cf plasma desorption mass spectrometry of polar agrochemical metabolitesPresented in part at the 36th American Society of Mass Spectrometry Conference, San Francisco, California, USA, 5-10 June, 1988. (1990)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 19 (1990), S. 75-79 
    Details
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The use of 252Cf plasma desorption (PD) mass spectrometry for the identification of highly polar agrochemical metabolites is illustrated with metabolites of azinphos-methyl, -ethyl, demeton-S-methyl and demeton-S-methyl sulphoxide. Three different classes of metabolites were used, namely the monosodium salt of organophosphorus acid ester, the glycoside and the sodium salt of sulphonic acid. Positive and negative ion mass spectra were recorded for different sample preparation techniques. The electrospray method and nitrocellulose adsorption with sample application by spin-drying with and without a rinsing step was applied and evaluated. PD mass spectrometry has proved to be useful in providing fast information on the molecular weight of all three classes of metabolites, but the method has failed to give fragment ions. The best result in terms of sensitivity and low background were obtained using the nitrocellulose spin-drying method without a washing step. It has been found to be a very valuable technique for the rapid identification of non-volatile or thermally labile agrochemical metabolites after high-performance liquid chromatographic isolation from plants.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200190205
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  • 8
    Electronic Resource
    Electronic Resource
    Structural characterization of the cyanelle peptidoglycan of Cyanophora paradoxa by 252Cf plasma desorption mass spectrometry and fast atom bombardment/tandem mass spectrometryDedicated to Professor Peter Krenmayr on the occasion of his retirement from the Technical University of Vienna. (1993)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 22 (1993), S. 524-536 
    Details
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A strategy for the structural characterization of the four major NaBH4-reduced peptidoglycan monomers derived from muramidase-digested peptidoglycan from the cyanelles of the flagellate Cyanophora paradoxa Korschikoff is described. Initial molecular weight determination of these glycopeptides was performed by positive and negative ion plasma desorption mass spectrometry. Due to the presence of two pairs of disaccharide tripeptide and disaccharide tetrapeptide monomers differing in mass by 112 units, respectively, an as yet unknown peptidoglycan modification either at the carbohydrate or at the peptide moiety was assumed. β-Elimination of the disaccharide unit from the unreduced peptidoglycan monomers yielded the corresponding (modified) N1-lactyltripeptides and -tetrapeptides, respectively. These peptides, N-terminally blocked with lactic acid, unambiguously showed the modification to be located on the peptide moiety. By positive ion fast atom bombardment/hybrid tandemmass spectrometry of the reduced peptidoglycan monomers as well as of the corresponding deglycosylated monomers (= N1-lactylpeptides) the modification was determined to be linked to the glutamic acid moiety. Based on combined data from plasma desorption mass spectrometry, tandem mass spectrometry, accurate mass measurement and amino acid analysis of the acid hydrolysate after derivatization with o-phthaldialdehyde by high-performance liquid chromatography we could establish the structure of the modification as N-acetylputrescine. Finally, the confirmation of the linkage of the glutamic acid to diaminopimelic acid via the γ-COOH was based on the presence of a-type peptide backbone fragment ions in the positive ion plasma desorption mass spectra of the modified N1-lactylpeptides.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200220906
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  • 9
    Electronic Resource
    Electronic Resource
    Quantitative determination of N-acetyl(-L-)cysteine derivatives in human urine by tandem mass spectrometry (1993)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 22 (1993), S. 133-142 
    Details
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Collision-induced dissociation (CID) methods are described for the quantification of nanogram per millilitre (ppb) concentrations of 2-acetamido-3-(3′-hydroxypropylthio)-propanoic acid (I) and 2-acetamido-3-phenylthiopropanoic acid (II) in human urine extracts. I and II are potential detoxification products of acrolein and benzene in conjugation with N-acetyl(-L-)cysteine derived from glutathione. We have studied the potential of tandem mass spectrometry (MS/MS) under electron impact (EI) and chemical ionization (CI) conditions as a confirmatory screening technique for these compounds. Our main goals were high selectivity and low detection limits along with little or no sample clean-up. The effects of the mode of ionization and of collision conditions on the CID spectra have been investigated. Direct insertion probe without any derivatization or short-column gas chromatographic separation techniques are used. Total instrument and data analysis time is about 15 min for direct insertion probe MS/MS and about 30 min for short-column gas chromatography (GC)/MS/MS. Detection limits are: direct insertion probe MS/MS (EI mode), 50 ppb (100 pg) for compound I; short-column GC/MS/MS (EI mode), 1.5 ppb (5 pg) for compound II; and short-column GC/MS/MS (CI mode), 0.6 ppb (2 pg) for the methyl ester of compound II. Results are compared with non-mass spectrometric methods. The MS/MS methods were applied for the determination of I (EI mode) and II (CI mode) in urinary samples of a smoker and eight non-smokers. After smoking, the urinary levels of I and II were elevated, whereas no increase was observed after experimental passive smoking.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200220206
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  • 10
    Electronic Resource
    Electronic Resource
    Enzymatic cleavage directly on the probe tip for mass spectrometric identification of peptides (1990)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 19 (1990), S. 159-163 
    Details
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Fast atom bombardment mass spectrometry was used in direct combination with enzymatic cleavages by endopeptidases for the identification of peptides derived from recombinant proteins. By this fast and simple reaction on the probe tip, the enzymes produced a mixture of smaller peptides. Molecular weights were calculated in advance and used for verification of the amino acid sequence of the original peptide as well as for partial structure determinations. Since the enzymatic reaction took place directly on the probe tip, sample material and time was saved. This technique may be applied especially in such cases where mass spectrometry alone does not give sufficient information and if the mass range of the instrument is limited, e.g. to 2000 daltons.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200190311
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