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  • 1
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    Analytical chemistry 61 (1989), S. 1202-1207 
    ISSN: 1520-6882
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    Analytical chemistry 63 (1991), S. 2888-2891 
    ISSN: 1520-6882
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Contact dermatitis 19 (1988), S. 0 
    ISSN: 1600-0536
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: 7-oxodehydroabietic acid and 15-hydroxydehydroabietic acid were isolated as their methyl esters from Portuguese colophony of the gum rosin type and identified as contact allergen. Another oxidation product of dehydroabietic acid, 15-hydroxy-7-oxodehydroabietic acid, was synthesized and identified as a component of Portuguese gum rosin. 7-oxodehydroabietic acid was found to a be a grade III allergen according to the GPMT method. Guinea pigs induced with gum rosin showed only a low response to the isolated compounds, while patients with a known allergy to gum rosin reacted to a greater extent. The result imply that the content of oxidized dehydroabietic acids in gum rosin is too low to give a marked sensitization in the animals. However, the patients might have come in contact with the allergens in technically modified rosins. The compounds showed a pattern of cross-reactivity in the animal experiments as well as among the patch tested patients.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1432-0738
    Keywords: Polymethylmethacrylate ; Methyl methacrylate ; Brain ; Lung
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Polymethylmethacrylate was thermally degraded in air at 300° C and the volatile decomposition products studied with gas chromatography-mass spectrometry. The main product was monomeric methacrylate, although many other compounds existed among the products. Electron spin resonance spectroscopy revealed the presence of free radicals. Wistar rats were exposed to the fumes of the plastic (300° C) and their lungs and brain studied for biochemical effects. In the lung, the activity of 7-ethoxycoumarin O-deethylase decreased and an initial inhibition of glutathione peroxidase and superoxide dismutase was observed. The contents of reduced nonprotein sulfhydryl groups were decreased in the lung and brain. The exposures enhanced the activities of acetylcholine esterase, creatine kinase and NADPH-diaphorase in the brain. Scanning electron microscopy of the exposed lungs showed disorganization of ciliated cells, and the epithelial serous cells (Clara cells) were damaged.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: An analytical method, based on a selective extraction and pyrolysis gas chromatography/mass spectrometry assay of arsenocholine and acetylarsenocholine in aquatic organisms, is described. Characteristic fragmentation patterns were obtained from pyrolytically demethylated compounds. The molecules were rearranged in unique pathways which differed from those of corresponding nitrogen analogues. Qualitative determination of arsenocholine and acetylarsenocholine was achieved by gas chromatographic as well as mass spectrometric analysis of the thermal degradation products (trimethylarsine, dimethylvinylarsine and the demethylated arsenocholine or acetylarsenocholine). Arsenocholine and acetylarsenocholine in fish from industrially polluted water were isolated and identified. Massfragmentographic quantification of the arsenic compounds in fish was carried out by use of deuterium labelled analogues of arsenocholine and acetylarsenocholine as internal standards. The method showed a high sensitivity.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 7 (1984), S. 185-190 
    ISSN: 0935-6304
    Keywords: Gas chromatography ; Capillary columns ; Mass spectrometry ; Dynamic headspace ; Deans switching ; Cold trap ; Reinjection ; Polymers ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: An experimental method for the analysis of volatile organic compounds in polymers is described. The technique involves dynamic headspace sampling, collection, and concentration of the volatiles in a cold trap, followed by capillary column gas chromatography/mass spectometry. Flow switching is carried out by the Deans switching technique. Four technical polymers used as pharmaceutical packaging materials have been analyzed in order to demonstrate the method.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 5 (1982), S. 236-244 
    ISSN: 0935-6304
    Keywords: Gas chromatography ; Capillary columns ; Rotary valve ; Cold trap ; Reinjection ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: This paper describes a cold trap/reinjection system for capillary columns which utilizes a flow switching rotary valve. Sample enrichment is performed in a liquid nitrogen-cooled glass trap attached to the valve. Evaporation of enriched compounds is carried out with the aid of an electric heating coil. Parameters such as cryogenic trapping efficiency, reinjection rates, transference of sample, and adsorption, as well as overall performance, are examined. In addition, a comparison is made between the cold trap/reinjection technique and injection with a gas-tight syringe.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 7 (1980), S. 265-268 
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A method is described for the determination of unconjugated terbutaline in plasma. The assay is based on gas chromatography chemical ionization mass spectrometry with ammonia as the reagent gas. Terbutaline and a deuterium labelled internal standard were isolated from plasma by ion exchange chromatography followed by extraction into t-butanol. Quantitation was performed by selected ion monitoring of the [MH]+ions m/z 442 and m/z 448 of the tri-O-TMS derivatives of terbutaline and the internal standard, respectively. Silylation was carried out in the presence of pyridine at room temperature and was complete within one minute. The overall recovery of terbutaline in the procedure was estimated at about 80%. Measurement of terbutaline down to 0.1 ng ml-1 in 4 ml of plasma is possible with a coefficient of variation of 8.6%. Day-to-day variation was found to be 6.0% at a level of 3.26 ng ml-1.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Thermal oxidation of isotactic polypropylene films at 120-280°C in air was studied. Separation and identification of the volatiles formed was carried out by gas chromatography-mass spectrometry. Sixteen products were tentatively identified for the first time. Altogether, 50 compounds representing hydrocarbons, ethers, alcohols, aldehydes, ketones, and acids are reported. Oxygen deficiency is manifested in diffusion-limited products of olefines, dienes, and aromatic compounds. The relative amounts of acetaldehyde and acetone are almost temperature independent in the range of 120-280°C. This indicates a similarity of oxidative degradation of the polymer in a broad temperature range. Addition of an antioxidant to the polymer depresses the evolution of the main volatiles by 9-10 times at 280°C. The relative amounts of the volatiles formed are, nevertheless, the same as for the polymer without an antioxidant. The mechanism of formation of the degradation products is discussed.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 27 (1982), S. 2539-2551 
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Thermal oxidation of isotactic polypropylene (PP) at 220 and 280°C in air was studied. Gas chromatography-mass spectrometric analysis was used to separate and identify the volatile products of PP oxidation. Twenty-three products were identified and 15 substances were quantified. The aldehydes are the principal products formed, followed by ketones, acids, and alcohols. The main organic product quantified was acetaldehyde. The volatile organic products formed constitute about 3% of the amount of water formed. The relative amounts of the most volatile products formed in the range 220-280°C are practically independent on the temperature of oxidation. The mechanism of formation on the oxidation products is discussed.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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