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  • 1975-1979  (1.075)
  • 1976  (1.075)
  • Analytical Chemistry and Spectroscopy  (566)
  • Chemical Engineering  (366)
  • Engineering  (143)
  • Engineering General  (143)
Materialart
Erscheinungszeitraum
  • 1975-1979  (1.075)
Jahr
  • 1
    Digitale Medien
    Digitale Medien
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 3 (1976) 
    ISSN: 1052-9306
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 2
    Digitale Medien
    Digitale Medien
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 3 (1976), S. 1-3 
    ISSN: 1052-9306
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The detection of a small amount of 13C labelled methyl benzoate and its metabolites in human urine dosed 13C labelled aspirin was carried out by a new mass fragmentographic technique.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 3
    Digitale Medien
    Digitale Medien
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 3 (1976), S. 4-13 
    ISSN: 1052-9306
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The mass spectroscopic behaviour of the methyl ester of prostaglandins E1 and E2 has been studied with the aid of low eV spectra, measurements on metastable ion decompositions and high resolution mass measurements. Mechanisms are proposed for the formation of the majority of the abundant fragment ions of these biologically important compounds. The mass spectra of free acids are also discussed.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 4
    Digitale Medien
    Digitale Medien
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 3 (1976), S. 21-27 
    ISSN: 1052-9306
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The biological implications, the reaction possibilities and the structure of different derivatives of N-hydroxy-2-fluorenylacetamide have been described.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 5
    ISSN: 1052-9306
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The amino acid sequence of a polypeptide can be deduced by an identification of all the dipeptides obtained from a Dipeptidylaminopeptidase I hydrolysate of the original polypeptide and its des N-terminal amino acid derivative. The components of such dipeptide mixtures can be readily identified from the chemical ionization (helium) mass spectra of their N-ethoxycarbonylpropenyl methyl ester derivatives without prior separation. The pyrolytic conversion of N-protected peptide dimethyltrideuteromethyl anilinium salts to their methyl esters in the direct insertion probe of a mass spectrometer was found to be most suitable for the derivatization of such dipeptide mixtures.
    Zusätzliches Material: 9 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 6
    Digitale Medien
    Digitale Medien
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 3 (1976), S. 48-49 
    ISSN: 1052-9306
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: A selective ion monitor for the Perkin-Elmer Model 270 gas chromatograph mass spectrometer is described.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 7
    Digitale Medien
    Digitale Medien
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 3 (1976), S. 50-50 
    ISSN: 1052-9306
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 8
    Digitale Medien
    Digitale Medien
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 3 (1976) 
    ISSN: 1052-9306
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 9
    ISSN: 1052-9306
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The mass spectral characterization of nine kinds of estrogen glucuronides was investigated. The glucuronides were analysed after conversion to n-propyl ester-O-TMS ether derivatives by gas chromatography mass spectrometry. The fragmentation of these derivatives is discussed using deuterium labels and TMS-d9 imidazole. A clear-cut difference was found between aliphatic and aromatic glucuronic acid conjugates. In particular the [M - 362]+· fragment ion was characteristic in the mass spectra of estrogen 3-glucuronides. On the other hand, four isomers of estriol and 16-epiestriol glucuronides containing an aliphatic acetal linkage were also characterized by the fragment ions of mle value 204, 345, 415 and 431 and their relative intensities. Thus, all nine estrogen glucuronides were discriminated mass spectrometrically.
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 10
    ISSN: 1052-9306
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The mass spectra of the dimethylphosphinic, dimethylthiophosphinic and dimethylphosphinous ester derivatives of several monohydroxy steroids are reported. The fragmentations of the derivatized steroids largely depend on the nature of the the phosphorus-containing ester group. Phenolic ester derivatives exhibit the base peak at the molecular ion, whereas the spectra of the secondary phosphinic esters are dominated by very intense protonated phosphinic acid ions [Me2 P(XH)(OH)]+ at m/e 95 (X = O) or at m/e 111 (X = S). The present results also indicate the low ionization potential for the phosphinic ester group. Due to their good gas chromatographic properties, these steroid derivatives appear to be particularly suitable for gas chromatographic mass spectrometric analysis of biochemical materials.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 11
    Digitale Medien
    Digitale Medien
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 3 (1976), S. 77-80 
    ISSN: 1052-9306
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Excellent resolution and subsequent identification of free organic acids extracted from mixed, unstimulated human saliva was obtained by gas chromatography using high resolution open tubular glass capillary columns coupled with mass spectrometry computer instrumentation. In addition to the organic acids, identified as their trimethylsilyl derivatives, the presence of 2,6-di-t-butylcresol - a food preservative - and cholesterol was established by mass spectrometry. The effects of aspirin ingestion as well as diurnal variation were studied to demonstrate the possible clinical significance of this noninvasive approach to metabolic profiling.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 12
    Digitale Medien
    Digitale Medien
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 3 (1976), S. v 
    ISSN: 1052-9306
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 13
    ISSN: 1052-9306
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The sterol compositions of three oceanic jellyfish have been determined using gas chromatographic mass spectrometric techniques involving the use of two separate gas chromatographic column systems. The components in overlapping peaks have been identified by comparison of the mass spectra of peaks in the two column systems using subtractive techniques. A mid-water animal, Periphylla periphylla, was found to contain a very complex and unusual sterol profile including rare 5α-stanols, whereas two other oceanic jellyfish Pelagia noctiluca and Atolla wyvillei contained similar mixtures of Δ5 sterols to those previously isolated from coastal species.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 14
    Digitale Medien
    Digitale Medien
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 3 (1976), S. 28-31 
    ISSN: 1052-9306
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: A general derivatization method has been developed for both primary and secondary aminoalkylphosphonic acids. Derivatization is effected by reaction with trifluoroacetic acid and trifluoroacetic acid anhydride followed by esterification using ethereal diazo-n-butane. This method can be used for microgram quantities and permits ready characterization by both gas chromatography and gas chromatography mass spectrometry. The structure of this derivative has been verified by mass spectrometry and proton magnetic resonance. Fragmentation patterns were confirmed by high resolution mass spectrometry, isotope labeling and the formation of derivative analogs.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
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  • 15
    Digitale Medien
    Digitale Medien
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 3 (1976), S. 45-47 
    ISSN: 1052-9306
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The measurement of diphenoxylic acid, the major metabolite of diphenoxylate, has been performed in man using a deuterium labelled internal standard and multiple ion monitoring using a gas chromatograph mass spectrometer. The determination of plasma concentrations following administration of diphenoxylate to man is described.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
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  • 16
    ISSN: 1052-9306
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The methyl ester of trifluoroacetic acid was prepared by reaction with N,N′-dimethylformamide dimethylacetal and was successfully passed through a gas chromatograph. Trifluoroacetic acid was detected by the use of gas chromatography and low and high resolution gas chromatography mass spectrometry in an acidic extract of an incubation medium containing microsomes, reduced nicotinamide adenine dinucleotide phosphate, oxygen and halothane. However, trifluoroacetic acid could not be detected when nicotinamide adenine dinucleotide or oxygen was omitted from the incubation system. From these results, it was proved that halothane is oxidatively metabolized to trifluoroacetic acid by hepatic microsomes.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
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  • 17
    Digitale Medien
    Digitale Medien
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 3 (1976), S. v 
    ISSN: 1052-9306
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 18
    Digitale Medien
    Digitale Medien
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 3 (1976), S. v 
    ISSN: 1052-9306
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 19
    ISSN: 1052-9306
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: A gas chromatographic mass spectrometric method has been developed for the rapid determination of a urinary tetrasaccharide (α-D-Glc-(1 → 6)-α-D-Glc-(1 → 4)-α-D-Glc-(1 → 4)-D-Glc). The urine sample is first fractionated by gel chromatography. An appropriate internal standard is added to the pooled tri-pentasaccharide fraction. Which is then reduced, methylated and fractionated by g.c. The identification of the tetrasaccharide derivative is based on the g.c. relative retention time and the mass spectrum of the reduced permethylated tetrasccharide derivative is based on the g.c. relative retention time and the mass spectrum of the reduced permethylated tetrasaccharide. The normal excretion rate was in the range of 0.1-2.5 mg per 24 hours. Greatly increased amounts (9.4-89.6 mg 24 h-1) were found in the urine of patients with glycogen storage disease type II and type III and in one patient with unclassified muscular disease. A moderate increase (3.6-8.6 mg 24 h-1) was observed in one patient with glycogen storage disease type VI. in two patients with Duchenne muscular dystrophy and in two other patients with unclassified muscular disease.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 20
    ISSN: 1052-9306
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Phenacetin, paracetamol and acetanilide can be determined in a plasma or urine sample by the use of deuterium labelled analogues. These are produced by reaction of hexadeuterioacetic anhydride with the appropriate aromatic amine. The -NHCOCD3 group is stable to hydrogen exchange below pH 8. The internal standard is added to the plasma or urine after enzymatic hydrolysis of the paracetamol conjugates and an ethyl acetate extract at pH 5 is evaporated under nitrogen and the residue derivatized with N, O-bis-(trimethylsilyl)-acetamide. An aliquot of this solution is injected into a g.c.m.s. system, and one ion characteristic of the material under study and the ion from the deuterium analogue (3 mass units greater) are monitored using a voltage switching technique. In the case of phenacetin, for example, ions at 251 and 254 are monitored. Calibration curves relating different weight ratios of the hydrogen and deuterium compounds to their respective signals from the gas chromatograph mass spectrometer are used to calculate the amount of a compound in a particular sample. These methods have been developed to study the oxidation of acetanilide to paracetamol and the de-ethylation of phenacetin to paracetamol. Preliminary results from experiments with phenacetin will be discussed.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
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  • 21
    Digitale Medien
    Digitale Medien
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 3 (1976), S. v 
    ISSN: 1052-9306
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 22
    Digitale Medien
    Digitale Medien
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 3 (1976), S. 196-200 
    ISSN: 1052-9306
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Organic vapors in ambient air, at or near an industrial site in Baltimore, Maryland, were collected by adsorption on a sorbent of porous polymer (Tenax GC, 35/60). The pollutants were recovered by thermal desorption and analyzed by gas-liquid chromatography mass spectrometry computer using capillary glass SCOT columns. N-Nitrosodimethylamine was identified from its mass spectrum as a constituent of the atmosphere in the areas sampled. The identification of this compound was confirmed by comparison of its mass spectrum with that of authentic N-nitrosodimethylamine; identical retention times of unknown and authentic compound on three different capillary columns were observed.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 23
    Digitale Medien
    Digitale Medien
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 3 (1976), S. 207-211 
    ISSN: 1052-9306
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: A selected ion monitoring assay has been developed to measure plasma levels of the bronchodilator pirbuterol in animals and man. Pirbuterol is extracted from plasma with acetone + potassium carbonate and after further purification is converted to its trimethylacetyl derivative. With the use of the stable isotope labeled internal standard, pirbuterol-d9, precisions of 10% and 6% were achieved at plasma concentrations of 1 and 20 ng ml-1, respectively. The synthesis of the deuterium labeled internal standard is described.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 24
    ISSN: 1052-9306
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: A quantitative mass fragmentographic method for the simultaneous determination of labeled and unlabeled propoxyphene in plasma is described. Dogs treated daily with propoxyphene-d0 were treated with a pulse dose of propoxyphene-d2 at day 20. It was found that following an initial rapid equilibrium phase levels of propoxyphene-d2 fell more rapidly than those of propoxyphene-d0. This result suggests that ‘deep’ pools of tissue bound propoxyphene exist which exchange very slowly with drug present in the central compartment. Experimental evidence is presented which demonstrates that the difference in behavior of propoxyphene-d0 and -d2 is not due to unanticipated secondary isotope effects.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 25
    Digitale Medien
    Digitale Medien
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 3 (1976), S. 226-229 
    ISSN: 1052-9306
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Urine from rats and sheep given single oral doses of [14C]propachlor contained 14C metabolites in which the chlorine of propachlor was replaced by a methylsulfonyl group. Methylsulfonyl-containing metabolites were also isolated from the urine of rats given an intraperitoneal dose of the cysteine conjugate of [14C]propachlor; this indicated that the methylsulfonyl-containing metabolites resulted from metabolic reactions subsequent to the mercapturic acid pathway.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
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  • 26
    ISSN: 1052-9306
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The methane chemical ionization spectra of a number of tertiary and quaternary amines with a N-trideuteromethyl group show substitution of this group by methyl. The isotopic purity of the original amines was shown to be 〉 99% using ammonia as a reagent gas.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
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  • 27
    ISSN: 1052-9306
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Catabolic intermediates of sodium dipropylacetate, an anticonvulsant drug, in the urine extracts of the drug-treated rats were examined by the aid of gas chromatography mass spectrometry. Eleven drug-specific peaks were estimated as unmetabolized sodium dipropylacetate, succinic acid, 2-n-propyl-3-hydroxypentanoic acid, 2-n-propyl-4-hydroxypentanoic acid, 2-n-propyl-3-oxopentanoic acid, 2-n-propyl-5-hydroxypentanoic acid, adipic acid, 2-n-propylglutaric acid, dipropylacetic acid glucuronide, propionic acid and 3-heptanone. Administration of sodium dipropylacetate with isoleucine to rats resulted in the disappearance of 2-n-propyl-3-oxopentanoic acid and a considerable decrease in 2-n-propyl-3-hydroxypentanoic acid. These data indicated that β-oxidation was involved in the metabolism of sodium dipropylacetate as well as glucuronide conjugation and ω-oxidation.
    Zusätzliches Material: 8 Ill.
    Materialart: Digitale Medien
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  • 28
    Digitale Medien
    Digitale Medien
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 3 (1976), S. v 
    ISSN: 1052-9306
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 29
    ISSN: 1052-9306
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: A sensitive method for the qualitative and semiquantitative determination of terbutaline in plasma and urine has been developed After a single oral dose of 5 mg terbutaline sulphate the drug could be analysed easily. The detection limit in plasma is less than 1 ng ml-1.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
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  • 30
    ISSN: 1052-9306
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Reductive methylation (the Eschweiler-Clarke reaction) was used as a route for the synthesis of differently deuterium labelled variants of trimethylamine with the ultimate aim of preparing labelled variants of choline and acetylcholine. Combinations of unlabelled and labelled formaldehyde and formic acid yielded symmetrically labelled trimethylamines of high isotopic purity. The labelled congerers to acetylcholine and choline that were prepared subsequently provide suitable internal standards and tracers to be used in mass spectral analysis and in the evaluation of the pharmacokinetics of the parent compounds.
    Zusätzliches Material: 1 Tab.
    Materialart: Digitale Medien
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  • 31
    Digitale Medien
    Digitale Medien
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 3 (1976), S. 272-277 
    ISSN: 1052-9306
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Using electron impact and field desorption mass spectrometry, structures are proposed for narasin and a related ionophore, A28086B, derived from fermentation. The ionic fragmentation of these compounds and their derivatives is discussed and compared with that of salinomycin, whose structure has been determined by X-ray diffraction.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
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  • 32
    Digitale Medien
    Digitale Medien
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 3 (1976), S. 281-285 
    ISSN: 1052-9306
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: A sensitive method for the simultaneous determination of bufuralol and its pharmacologically active metabolites in human plasma is described. The O-trimethylsilyl,N-trifluoroacetyl derivatives are assayed by mass fragmentography. Sensitivity is 1 ng ml-1 plasma for bufuralol and about 250 pg ml-1 for the metabolites. An alternative procedure which uses gas chromatography with electron capture detection is also described. The sensitivity of this is about 10 ng ml-1 plasma for all drug-related components.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
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  • 33
    Digitale Medien
    Digitale Medien
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 3 (1976) 
    ISSN: 1052-9306
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 34
    ISSN: 1052-9306
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: A low resolution, high sensitivity study has been made of the field desorption mass spectrum of glucagon, a 29 amino acid residue underivatized peptide. The highest molecular weight fragments observed, when spectra were taken under conditions which minimized surface reactions of the peptide on the emitter, were found to contain no more than 18 amino acid residues. The most probable fragmentation processes for ions larger than m/e 600 were the production of fragments containing 10, 11 or 12 amino acid residues.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
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  • 35
    Digitale Medien
    Digitale Medien
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 3 (1976), S. 217-225 
    ISSN: 1052-9306
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Through the combined use of stable isotope labeling and gas chromatographic mass spectrometric analysis, the metabolic patterns for propoxyphene have been determined in laboratory animals and man. The rat and dog eliminated propoxyphene and its metabolites principally via the bile, while the rabbit more closely resembled man in excreting the metabolic products into urine. Metabolites in rat and rabbit existed as conjugates, whereas in dog and man the metabolites were excreted as a mixture of the free and unconjugated forms. The primary route of metabolism in all species studied was N-demethylation. However, the rat and rabbit extensively hydroxylated propoxyphene and its metabolltes prior to elimination. Metabolites arising from ester hydrolysis were found in rat and man. N-acetylated products were identified in all four species. A metabolite formed from cyclization and dehydration of dinorpropoxyphene was isolated in urine and was further identified as a circulating metabolite in dog plasma.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
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  • 36
    Digitale Medien
    Digitale Medien
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 3 (1976), S. 232-234 
    ISSN: 1052-9306
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Gentamicin sulphate employed in therapeutics consists of a mixture of three major aminoglycoside components, the gentamicins C1, C1a and C2. In the electron impact mass spectra of these components weak parent ions may be observed but they are of no diagnostic value in the commercial mixture. Chemical ionization and field desorption spectra of individual gentamicin components and commercial mixtures are reported and discussed. Isobutane chemical ionization spectra exhibit some fragmentation, but under optimum field desorption conditions little glycosidic cleavage is observed and [M + H]+ ions dominate the spectra.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
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  • 37
    Digitale Medien
    Digitale Medien
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 3 (1976), S. 295-298 
    ISSN: 1052-9306
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The concentration of oestrone, oestradiol and progesterone in ovarian tissue have been determined directly by quant tative high resolution mass fragmentography without the necessity of extraction or purification. The changes in the levels of these steroids in the ovary throughout a 28 day period correlate well with those measured in plasma and also with those of the corresponding metabolites excreted in urine. Some benign ovarian tumours (cysts) have been shown to contain abnormally large amounts of progesterone.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
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  • 38
    Digitale Medien
    Digitale Medien
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 3 (1976), S. 166-171 
    ISSN: 1052-9306
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The mass spectra of peracetylated daunorubicin, N-octanoyl-, N-dodecanoyl- and N-(N'-dodecanoylglycyl)daunorubicin, and perdeuteroacetylated N-dodecanoyldaunorubicin were analyzed. Major fragmentation pathways were suggested and ion compositions were determined by high resolution measurements.
    Zusätzliches Material: 3 Tab.
    Materialart: Digitale Medien
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  • 39
    ISSN: 1052-9306
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Field desorption mass spectra have been obtained for dipalmitoylphosphatidyl choline-d0, -d4 and -d9. The two latter compounds were synthesized from dimethylene-d4 choline bromide and trimethyl-d9 choline bromide, respectively. Comparison was made of spectra of these three compounds obtained at different field anode temperatures in order to establish the composition of the major cleavage, rearrangement, and association ions. At low anode heating currents (≤ 20 mA) the most intense peak is [M + 1]+ which accounts for c. one-third of the total ionization. At higher temperatures various fragmentation processes, some of which are without analogy in electron impact mass spectrometry, become more important. The presence of an intermolecular methyl transfer process has been confirmed.
    Zusätzliches Material: 1 Tab.
    Materialart: Digitale Medien
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  • 40
    ISSN: 1052-9306
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: A gas chromatographic mass spectrometric method for the quantitative determination of imipramine and its N-demethylated metabolite desipramine in plasma samples at the nanogram level is reported. The method involves derivatization of the extracted drugs with trifluoroacetylimidazole, a mild derivatizing reagent. Specificity is provided by selected ion recording of the [M + H]+ ions, formed upon chemical ionization with methane as reagent gas. Quantitation is achieved by stable isotope dilution techniques, using deuterium labeled analogs, prepared by acid-catalyzed exchange, as internal standards. Data on patient samples are presented.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
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  • 41
    Digitale Medien
    Digitale Medien
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 3 (1976), S. 316-328 
    ISSN: 1052-9306
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Phosphates and phosphoramidates related to 2-chloro-4-t-butylphenyl methyl methylphosphoramidate (crufomate) were synthesized to aid in the identification of crufomate metabolites. Deuterium labeling, metastable determinations and precise mass measurements were used to establish fragmentation pathways. Evidence was obtained for the rearrangement of an N-formyl phosphoramidate (the expected result of oxidative metabolism of N-methyl phosphoramidates) to an iminomethyl phosphate.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
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  • 42
    Digitale Medien
    Digitale Medien
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 3 (1976), S. 335-339 
    ISSN: 1052-9306
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Metabolites of the antitumor agent, ellipticine (NSC 71795), are mainly secreted in rat bile as two conjugates of hydroxylated ellipticine. The possible involvement of an arene oxide intermediate prior to hydroxylation and conjugation has been studied using 7,9-dideutero-ellipticine and by determining the conservation of deuterium in the phenolic products. The deuterated drug was synthesized by acid catalyzed exchange and was characterized by nuclear magnetic resonance and high and low resolution mass spectrometry. Mass spectra of two conjugated metabolites from rat bile showed a mass ion at m/e 263 (singly deuterated hydroxylated ellipticine). There was no evidence for conservation of deuterium at the position of hydroxylation (m/e 264). These results indicate that the major pathway of metabolism for this cancer chemotherapeutic drug, prior to conjugation and excretion in rat bile, proceeds by aromatic hydroxylation apparently without involving an arene oxide/NIH shift mechanism.
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
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  • 43
    Digitale Medien
    Digitale Medien
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 3 (1976) 
    ISSN: 1052-9306
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 44
    ISSN: 1052-9306
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Endogenous tryptamine, 5-hydroxytryptamine, indoleacetic acid, 5-hydroxyindoleacetic and tryptophan have been recovered from urine and cerebro-spinal fluid by adsorption on XAD-2 resin (0.3 g). After adsorption of the sample on the resin, desorption with methanol provides a single fraction that contains all of these metabolites. The mass spectra of their pentafluoropropionyl derivatives show prominent ions at m/e 276 and 438 which are characteristic of indoles and 5-hydroxyindoles, respectively, a feature that allows the concurrent determination of all the components of each group by functional group analysis. A method has been developed to carry out single ion monitoring with the peak matching system of an Hitachi RMU-6H mass spectrometer. Identifications are based on the respective Kovats Indices and single ion monitoring of two characteristic ions per compound: tryptophan (m/e 276 and 347); tryptamine (m/e 276 and 289); indoleacetic acid (m/e 276 and 335); 5-hydroxytryptamine (m/e 438 and 451); 5-hydroxyindoleacetic acid (m/e 438 and 497). The method described illustrates the feasibility of assaying biogenic indoleamines and acidic metabolites, as well as their precursor amino acid on a single fraction in contrast to other standard fractionation methods. This is possible even if the mass spectrometer is not equipped with an alternating voltage accelerator provided that it has a peak matcher, although the lack of an alternating voltage accelerator requires two separate injections of the same sample, for quantification and identification; one for the indole profile and another for the 5-hydroxyindole profile. Both profiles can be verified by individual monitoring of the other confirmatory ions. With this method the use of a multiple ion detector would allow a simultaneous determination of all of these metabolites in one gas chromatograph mass spectrometer run.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
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  • 45
    ISSN: 1052-9306
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: An improved method is described for measuring low levels of prostaglandin F2α in small volumes of cerebrospinal fluid. Single ion monitoring of the ion at m/e 423. derived from the methyl ester tri-TMS ether derivatives of prostaglandin F2α and the internal standard, ω-trinor-16-cyclohexyl prostaglandin F2α, is employed. Injection of 2 pg of prostaglandin F2α derivative gave a standard deviation of ±9%. The majority of patients had cerebrospinal fluid levels of up to 2 ng ml-1 of prostaglandin. F2α, whereas in certain neurological conditions with progressive disease, elevated levels were encountered, some of which were higher than 10 ng ml-1.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
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  • 46
    Digitale Medien
    Digitale Medien
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 3 (1976), S. 122-126 
    ISSN: 1052-9306
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Trimethylsilyl derivatives of 1-hexadecyl-2-decanoyl-, -hexadecanoyl- and -octadecenoylglycerols and 1-octadecyl-2-decanoyl-, -hexadecanoyl- and -octadecenoylglycerols as well as 1,2-dihexadecanoylglycerol were analysed by a gas chromatograph mass spectrometer system. The following points are characteristic of the fragmentation pattern of these 1-alkyl-2-acyl derivatives: (1) in the spectra of alkyl acyl derivatives, ions at [M - 15]+ and [M - 90]+· are 14 mass units less than those of the corresponding diacyl derivatives; (2) the base peak is m/e 130; (3) alkyl acyl derivatives show fragments due to one acyl group instead of the two acyl groups of diacyl derivatives; (4) ions at m/e 314 and 342, [R10 + 73]+·, are characteristic of the trimethylsilyl derivatives of hexadecyl- and octadecylglycerols, respectively; (5) the ion [M - R10]+ is present, but the complementary alkoxy ion is absent.
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
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  • 47
    Digitale Medien
    Digitale Medien
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 3 (1976), S. 137-139 
    ISSN: 1052-9306
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Six major components of a mixture of the pyrolysis products of deoxyribonucleic acid have been analysed by combined low energy electron impact and collisional activation spectra. The method allowed the assignment of the structures of the different components in the complex mixture without prior separation.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
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  • 48
    Digitale Medien
    Digitale Medien
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 3 (1976), S. 146-148 
    ISSN: 1052-9306
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: α,α,β,β-d4-Serotonin (94% d4, 6% d3) has been synthesized for use as an internal standard in mass spectrometric determinations of serotonin in biological systems.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
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  • 49
    Digitale Medien
    Digitale Medien
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 3 (1976), S. 149-150 
    ISSN: 1052-9306
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 50
    Digitale Medien
    Digitale Medien
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 3 (1976), S. 151-154 
    ISSN: 1052-9306
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Correlations between mass spectra and pharmacological activities were surveyed by means of computerized learning machine and cluster analysis. The principal component analysis and the nonlinear mapping techniques were used for the feature selection of the data set.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
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  • 51
    Digitale Medien
    Digitale Medien
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 3 (1976), S. 191-195 
    ISSN: 1052-9306
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The terminal amino group of amino acids and peptides is blocked as the N-succinyl derivative by reaction with succinic anhydride. The product is then converted to the N,O-permethyl derivative in order to increase its volatility for use in mass spectrometry. The permethylated N-succinyl derivative retains the advantages of the permethylated N-acetyl derivative in regard to ease of preparation on a small scale, volatility and the presence of characteristic fragmentation patterns in their mass spectra. However, peaks in the high mass region are more abundant due to loss of CH3O· from the N-succinyl carbomethoxyl group as well as from the C-terminal carbomethoxyl group. Ions characteristic of the sequence and of individual amino acids are observed, and molecular weight can be determined from the relatively abundant ion at [M — CH3O]+ and from the weak molecular ion.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
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  • 52
    Digitale Medien
    Digitale Medien
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 3 (1976), S. 71-76 
    ISSN: 1052-9306
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The use of the mass spectrometric integrated ion current technique for the quantitative analysis of some trace metals at their tetraphenylporphyrin chelates is described. The linearity of the calibration curves and the sensitivity of the technique are improved by employing deuterated tetraphenylporphyrin chelates as loading agents. Femtomole quantities of the chelates may be detected. The use of deuterated tetraphenylporphyrin chelates as internal standards overcomes the problems of losses occurring during chromatographic separation and by thermal decomposition in the mass spectrometer.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
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  • 53
    Digitale Medien
    Digitale Medien
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 3 (1976), S. 88-90 
    ISSN: 1052-9306
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Isomeric chlorinated biphenyls are observed to yield very similar mass spectra, rarely exhibiting a [M — Cl]+ fragment of any siVgnificant magnitude. However, those isomers containing three ortho chloro substituents display a relatively intense [M — Cl]+ fragment. A rationalization for this observation is put forth on the basis of the relative stabilities of both product and reactant.
    Zusätzliches Material: 1 Tab.
    Materialart: Digitale Medien
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  • 54
    ISSN: 1052-9306
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The metabolism of 5-(4′-chloro-n-butyl)picolinic acid, which inhibits dopamine β-hydroxylase and exhibits an antihypertensive effect, has been studied by gas chromatography mass spectrometry, utilising characteristic reaction products after derivatization. In rat urine five metabolites were identified by mass spectral analysis. It is found that four were elongated by a C2 unit in the carboxyl group at the 2-position on the pyridine ring and accounted for approximately 50% of the radioactivity in the 24 hour urine. The facts show that the metabolic pathway corresponding to the chain elongation of fatty acids is the major route of metabolism for this drug in the rat. Furthermore, this pathway would be confirmed in man, rabbit, guinea pig and mouse.
    Zusätzliches Material: 11 Ill.
    Materialart: Digitale Medien
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  • 55
    Digitale Medien
    Digitale Medien
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 3 (1976), S. 248-254 
    ISSN: 1052-9306
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The electron impact and the hydrogen and methane chemical ionization mass spectra of 5,6-dihydro-2-methyl-1,4-oxathiin-3-carboxanilide, the sulfoxide and sulfone derived therefrom, and 2-(2-hydroxyethylthio)-acetoacetanilide enol have been determined. All four compounds show abundant molecular ions in the electron impact spectra and abundant [MH]+ ions in the methane chemical ionization spectra (along with the expected [M + C2H5]+ and [M + C3H5]+ ions), but relatively low [MH]+ ion signals in the hydrogen chemical ionization spectra. From high resolution mass measurements and metastable transitions determined by metastable ion refocusing, electron impact fragmentation mechanisms have been established. For 5,6-dihydro-2-methyl-1,4-oxathiin-3-carboxanilide, 5,6-dihydro-2-methyl-1,4-oxathiin-3-carboxanilide-4-oxide and 5,6-dihydro-2-methyl-1,4-oxathiin-3-carboxanilide-4,4-dioxide the major fragmentation mode involves loss of the anilino radical from [M]+, followed by loss of C2H4. Fragmentation to form the aniline molecular ion increases in importance with increasing oxidation state of the sulfur. In the chemical ionization of these three compounds fragmentation of [MH]+ proceeds in a similar fashion by loss of neutral aniline and by formation of protonated aniline. The electron impact mass spectrum of 2-(2-hydroxyethylthio)acetoacetanilide is dominated by the molecular ion and the aniline molecular ion. However, in the chemical ionization mass spectra characteristic fragment ions involving loss of water and loss of aniline from [MH]+, as well as protonated aniline, are observed and serve to characterize the compound.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
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  • 56
    Digitale Medien
    Digitale Medien
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 3 (1976) 
    ISSN: 1052-9306
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 57
    Digitale Medien
    Digitale Medien
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 3 (1976), S. 261-264 
    ISSN: 1052-9306
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Polyunsaturated fatty acids of human serum were analysed by combination gas-liquid chromatography and chemical ionization mass spectrometry, using isobutane as the reagent gas. The method described yielded the molecular ion of long chain unsaturated fatty acids as the base peak; these were weak or unobservable in the corresponding electron impact mass spectra. In the chemical ionization mass spectromtery, the derivatization with trimethylsilyl ether was demonstrated to be useful for the location of the double bonds of unsaturated fatty acids. Applied to the serum polyunsaturated fatty acids, these methods have given identification of C18:4, C20:4, C20:5, C22:4, C22:5ω-6, C22:5ω-3, and C22:6.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
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  • 58
    Digitale Medien
    Digitale Medien
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 3 (1976), S. 278-280 
    ISSN: 1052-9306
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The electron impact fragmentation of 1, 2-O-isopropylidene-α-D-glycero-tetros-3-ulofuranose has been studied with the help of deuterium and 18O labelling. The effect of substituting a hydrogen atom of C-4 for a CH3· radical and that of replacing the carbonyl function with a cyanomethylenic substituent is also reported.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
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  • 59
    Digitale Medien
    Digitale Medien
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 3 (1976), S. 265-271 
    ISSN: 1052-9306
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The use of linear regression analysis for the reduction of isotope dilution data is reviewed. The calculation of linear regression statistics is based upon four assumptions: zero variance in the independent variable, equal variance for all values of the dependent variable, linearity and continuity. Unfortunately, isotope dilution data often violate one or more of these assumptions, which results in the calculation of an inaccurate calibration line. The inaccuracies can be avoided through careful inspection of the data, including analyses of variance and linearity. Large differences in the variances of the dependent variable require the use of a weighted linear regression. Nonlinearity necessitates either discarding data in the nonlinear portion of the calibration or the calculation and use of atom % excess and dilution instead of the simple isotope ratios.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
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  • 60
    Digitale Medien
    Digitale Medien
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 3 (1976), S. v 
    ISSN: 1052-9306
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 61
    Digitale Medien
    Digitale Medien
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 3 (1976), S. 340-345 
    ISSN: 1052-9306
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The apparent discrepancy between theory and experimental practices in field desorption mass spectrometry has encouraged a study attempting to focus theoretical concepts more clearly into forms recognizable to the chemical investigator. Preliminary results indicate that best anode temperature for many compounds is independent of the applied voltage throughout the range available on the Varian MAT CH-5 double focusing mass spectrometer with the electron impact-field ionization-field desorption combined source. Studies of mass transfer indicate that desorption of the sample at the best anode temperature occurs in the absence of the applied field and at a rate which is indistinguishable from the rate of desorption in the presence of the field. These results and other observations, have led us to postulate a new mechanism of ion formation, involving chemical attachment reactions in a thin fluidized system. Clearly, the role of the field in this technique must be the subject of continued study.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
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  • 62
    Digitale Medien
    Digitale Medien
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 3 (1976), S. 81-87 
    ISSN: 1052-9306
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Thirty-six Δ5- and 5α-3β-hydroxysteroids have been oxidized with cholesterol oxidase to give the corresponding Δ4- and 5α-3-ketosteroids, respectively. The mass spectral characteristics of the products (or their trimethylsilyl ether derivatives, in the case of 3-keto-hydroxysteroids) varied considerably, depending especially on the nature of the C-17 sidechain. The ion of m/e 124 (or its equivalent) from cleavage of ring B was frequently a major fragment from Δ4-3-ketosteroids, but in some instances was of insignificant abundance. Trimethylsilylation of the product of the oxidation of neoergosterol gave neoergosterone enol-trimethylsilyl ether. Fragmentations of the sidechain oredominated in the mass spectra of the 5α-3-ketosteroids.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
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  • 63
    Digitale Medien
    Digitale Medien
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 3 (1976), S. 97-99 
    ISSN: 1052-9306
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 64
    ISSN: 1052-9306
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Gas chromatographic analysis of the products of reaction of diazomethane with tolbutamide and chlorpropamide indicates the formation of three compounds in both cases. As expected, N-methylation (at sulfonamide nitrogen) is the predominant reaction; minor amounts of O-methylated product are also observed. The third product in both cases is the N-methylsulfonamide formed by decomposition of the N-methylated sulfonylurea during gas chromatography. Electron impact and chemical ionization mass spectrometric analysis, as well as 1H nuclear magnetic resonance examination of samples collected from gas chromatography, confirm the structural assignments. Additionally, proton magnetic resonance analysis of the crude reaction products established that N-methylsulfonamides are not formed in the course of the diazomethane reaction and that the O-methylated derivatives are true products of the reaction. The use of a paramagnetic shift reagent allowed direct estimation of the ratios of N- to O-methylation, and the demonstration that these ratios are not vitiated during gas chromatographic analysis.
    Zusätzliches Material: 16 Ill.
    Materialart: Digitale Medien
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  • 65
    Digitale Medien
    Digitale Medien
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 3 (1976), S. 127-136 
    ISSN: 1052-9306
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The mass spectroscopic behaviour of prostaglandin F2α and its methyl ester has been studied. Mechanisms are suggested for the formation of the prominent ions in the spectra of these compounds. The proposed fragmentation pathways have been confirmed with the aid of low electron voltage spectra, measurements on metastable ion decompositions, high resolution mass measurements and deuterium labelling.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
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  • 66
    Digitale Medien
    Digitale Medien
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 3 (1976), S. v 
    ISSN: 1052-9306
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 67
    Digitale Medien
    Digitale Medien
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 3 (1976) 
    ISSN: 1052-9306
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 68
    Digitale Medien
    Digitale Medien
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 3 (1976), S. 155-160 
    ISSN: 1052-9306
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The β, γ and δ isomers of bilirubin-IX show a decreased stability as compared with the IXα isomer; characteristic mass spectra are obtained only for the tetrakis-(trimethylsilyl) derivatives of the IXα and IXγ isomers. Hydrogenation of the vinyl substituents increases the thermal stability of the bilirubins and gives rise to a characteristic mass spectrum for the tetrakis-(trimethylsilyl) derivative of meso-bilirubin-IXδ. The ethyl anthranilate azopigments derived from the four bilirubins yield characteristic mass spectra, except for the two unstable divinyl substituted azodipyrroles (mol.wt. 416), derived from bilirubin-IXβ and IXδ. The corresponding mol.wt. 420 azopigments derived from the hydrogenated bilirubins are thermally stable. Elucidation of mass spectral fragmentation pathways is facilitated by the varying positions of the substituents and by deuterium labelling, and permits the assignment of structures to the various isomeric azodipyrroles.
    Zusätzliches Material: 3 Tab.
    Materialart: Digitale Medien
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  • 69
    ISSN: 1052-9306
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The electron impact and chemical ionization (isobutane) mass spectra of the TMS derivatives of 20-hydroxy-5α-pregnan-3-ones and 20-hydroxy-4-pregnen-3-ones include ions [M — 44]+· attributable to loss of a CH3CHO fragment from C-17 with migration of the TMS group to the charge-retaining fragment. Mass spectra of isotopically labelled ([3-18O], [20-18O] and [2H9-TMS]) analogues are consistent with this mechanism; [2H9-TMS] labelling further indicates that subsequent loss of a methyl group from [M — 44]+· ions does not involve the TMS group. Corresponding ions are not observed at significant abundance in the spectra of 20β-trimethyl-silyloxy-5α-pregnane and 20β-trimethylsilyloxy-4-pregnen-3-one 3-O-methyloxime. In the electron impact mass spectrum of the t-butyldimethylsilyl ether of 20β-hydroxy-4-pregnen-3-one, an ion is observed corresponding to loss of 44 atomic mass units from the intense [M — C4H9]- ion.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
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  • 70
    Digitale Medien
    Digitale Medien
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 3 (1976), S. 177-183 
    ISSN: 1052-9306
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Fragmentation reactions of the biologically important N6-(3-methyl-2-butenyl)adenyl moiety have been re-examined with the aid of systematic deuterium labeling in the sidechain and by examination of the 1- and 7-deazanucleoside analogs. It is concluded that the diagnostic reactions which involve expulsion of C3H7 proceed predominantly by ring closure from the sidechain double bond to N-1 (ion a). Base-containing ions m/e 135 and 148 were confirmed to arise mainly by rearrangement of hydrogen from the methyl terminus to N6 and simple cleavage, respectively, but with significant contribution from other pathways involving transfer of sidechain hydrogens to the base.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
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  • 71
    Digitale Medien
    Digitale Medien
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 3 (1976), S. v 
    ISSN: 1052-9306
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 72
    ISSN: 1052-9306
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Two methods are described for the determination of salbutamol in human plasma. The drug is extracted from the plasma as a salbutamol tetraphenylboron ion pair and determined by gas chromatography mass spectrometry. Trideuterio-salbutamol is used as an internal standard. In the first method an extensive purification procedure is used to separate salbutamol from plasma cholesterol which interferes in the assay. Salbutamol is then determined as its TMS-ether using a multiple ion recording technique to measure the intensity of the fragment ion m/e 369 and the ion m/e 372 from the TMS ether of trideuterio-salbutamol. The second method is based on the ion pair extraction of salbutamol into heptan-3-one and its determination by gas chromatography mass spectrometry as the t-butyldimethylsilyl ether. The base peak in the mass spectrum of the t-butyldimethylsilyl-salbutamol is ion of m/e 495, which is of sufficiently high mass to distinguish it from any of the ions which arise from t butyldimethylsilyl-cholesterol. Six replicate analyses of plasma samples containing 1 ng salbutamol ml-1 were carried out using both methods. When the first method was used the mean value obtained was 1.3 ng ml-1 and the coefficient of variation was 17.7%. When the second method was used the mean value obtained was 0.95 ng ml-1 and the coefficient of variation was 10%. The second method is more rapid and therefore preferable for use in clinical pharmacological studies. This method has been used to determine the plasma salbutamol concentrations at varying times after either a 4mg oral or a 200 μg intravenous dose of salbutamol to man.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
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  • 73
    Digitale Medien
    Digitale Medien
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 3 (1976), S. 241-244 
    ISSN: 1052-9306
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The reaction products of trifluoroacetic anhydride with peptide amides are identified as stable heterocyclic imidazolin-5(4)-ones, which can be analysed by gas chromatography mass spectrometry. The mass spectra show intense molecular ions and allow the assignment of the amino acid sequence.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
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  • 74
    Digitale Medien
    Digitale Medien
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 3 (1976), S. 245-247 
    ISSN: 1052-9306
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Field desorption mass spectra of methotrexate and folic acid analogs yield abundant molecular or quasimolecular ions. At emitter currents above the best anode temperature, fragment ions which are useful as further confirmations of structures are observed.
    Materialart: Digitale Medien
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  • 75
    ISSN: 1052-9306
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The identification of a number of metabolites of the novel antiarrhythmic agent, α,α-dimethyl-4-(α,α,β,β-tetrafiuorophenethyl)benzylamine (MK-251), is presented. The compound is extensively metabolized by dog, monkey, baboon and man. Similar metabolic profiles were obtained for all species. Isolation and purification were accomplished by solvent extraction and chromatographic (column, gas and thin-layer) procedures. Gas chromatography, derivatization, infrared, nuclear magnetic resonance and particularly combined gas chromatography low and high resolution mass spectrometry techniques were employed to characterize the metabolites. The major urinary and plasma metabolites were identified as 2-[4-(α,α,β,β-tetrafluorophenethyl)phenyl]-2-propanol and its glucuronide conjugate. Other metabolites characterized were: the N-glucuronide of MK-251; 2-[4-(α,α,β,β-tetrafluorophenethyl)phenyl]propene; 2-nitro-2-[4-(α,α,β,β-tetrafluorophenethyl)phenyl]propane; α,α,β,β-dimethyl-4-(α,α,β,β-tetrafluorophenethyl)benzyl methyl ether; and 4-(α,α,β,β-tetrafluorophenethyl)acetophenone. The O-methyl ether metabolite represents the first instance of in vivo alkylation of a tertiary alcohol. Tentative identification was made for the N-hydroxy analog of MK-251 and for the glycol analog of 2-[4-(α,α,β,β-tetrafluorophenethyl)phenyl]-2-propanol. The observed pharmacological response appears to result mainly from MK-251 and not from the four metabolites.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
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  • 76
    ISSN: 1052-9306
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Twenty-five metabolites were isolated from the urine, feces or plasma of sheep given single oral doses of [14C]crufomate (4-t-butyl-2-chlorophenyl methyl methylphosphoramidate). These metabolites resulted from one or more of the following transformations: oxidation of a methyl group in the t-butyl moiety to yield either an alcohol or a carboxylic acid; hydrolysis of the phosphate and phosphoramidate bonds; oxidation of the N-methyl group to yield N-formyl phosphoramidates; methylation of the N-formyl group to yield N-methyl-N formthyl phosphoramidates; oxidative N-demethylation; conjugation with glucuronic acid. No ring-hydroxylation or dechlorination was observed, and no crufomate was isolated from the urine, feces or plasma.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
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  • 77
    ISSN: 1052-9306
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Seven sheep metabolites of crufomate (4-t-butyl-2-chlorophenyl methyl methylphosphoramidate) were characterized as glucuronide conjugates by interpretation of mass spectral data obtained from the pertrimethylsilyl derivatives and the trimethylsilyl derivatives of the methyl esters.
    Zusätzliches Material: 6 Tab.
    Materialart: Digitale Medien
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  • 78
    Digitale Medien
    Digitale Medien
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 16 (1976), S. 742-746 
    ISSN: 0032-3888
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Mold flows and melt viscosities of an incompatible bi-component EPDM and “Viton” fluoroelastormer system were examined. A marked reduction in the melt viscosities of either component was observed when a small amount of the other component was present. It was speculated that the phenomenon was a result of a slippage between the polymer and the coated capillary surface due to the presence of a minor amount of the incompatible polymer. Evidence is given to indicate that this effect cannot be accounted for using the “melt structural heterogeneity” mechanism proposed for a different system by Andtrianova.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
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  • 79
    ISSN: 0032-3888
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: The Part I paper described the mechanochemical basis for achieving high adhesive strength in bonds between polymeric surfaces such as polyethylene, polypropylene, and Teflon, using the SABRA method (Surface Activation Beneath Reactive Adhesives). This paper gives a brief survey of bonding techniques as well as results of shear tests of simple lap joints and scarfed tube joints. They compared favorably with other methods such as CASING, Peeling test results are also presented. Mixed systems were examined such as glass fiber reinforced polyester bonded to polypropylene and aluminum with thin films of polymeric material sandwiched between. A start was made towards of optimization and exploration of primer specificity for different materials, The implications and further applications of the SABRA method are discussed.
    Zusätzliches Material: 13 Ill.
    Materialart: Digitale Medien
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  • 80
    Digitale Medien
    Digitale Medien
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 16 (1976), S. 771-776 
    ISSN: 0032-3888
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Various blends over extended compositional ranges have beer, prepared for combinations of a thermoplastic urethane elastomer with polystyrene, a styrene-acrylonitrile copolymer, a polyhydroxyether (Phenoxy A), and poly(vinyl ethyl ether). The thermoplastic urethane elastomer was based on a polycaprolactone diol of approximately 2100 number average molecular weight, 4,4′-diphenylmethane diisocyanate and 1,4-butanediol at a molar ratio of 1/2/1, respectively. At ambient temperature, the tensile properties of the blends typically are intermediate between the values of the two separate components. Characterizations of the dynamic mechanical properties of the blends show the relative degree of compatibility for the thermoplastic urethane elastomer and the respective polymers. Two separate glass transitions are obtained for blends of polystyrene and the styrene-acrylonitrile copolymer with the thermoplastic urethane elastomer. This behavior demonstrates that these blend systems are incompatible. The blends of Phenoxy A and the thermoplastic urethane elastomer exhibit a single glass transition for which the temperature is dependent on the respective concentration of the components. These mixtures are considered to be compatible in nature.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
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  • 81
    Digitale Medien
    Digitale Medien
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 16 (1976), S. 803-810 
    ISSN: 0032-3888
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Trifunctional poly-ε-caprolactone polyol was polymerized with a chain-extended 1,6-hexane diisocyanate, and the rheology followed by cone and plate flow. Viscosity was found to be independent of shear rate up to at least 102 N.s/m2 (103 poise) and 30s-1. Extent of reaction was monitored by a periodic titration for isocyanate groups. Using branching theory, viscosity was related to extent of reaction and temperature. Such relations should be useful for process models. Normal force data for the curing system are also reported.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
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  • 82
    Digitale Medien
    Digitale Medien
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 16 (1976), S. 811-816 
    ISSN: 0032-3888
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Melt How data has been determined for a series of fractionated and whole low density polyethylenes which has been characterized in terms of their molecular weights and degree of long-chain branching, (LCB). The resulting data indicate that low LCB influences melt flow both through a reduction in molecular size and an increased level of intermolecular interaction. Die swell measurements on whole polymers indicate an increase in melt elasticity with increase in degree of LCB for samples of similar melt flow (MI). Comparison of GPC data with observed die swell characteristics indicates that die swell is a molecular size dependent property and independent of intermolecular entanglement effects, suggesting that the measurement of elastic properties of LDPE melts will provide a means of determining relative degrees of LCB for commercial resins.
    Zusätzliches Material: 9 Ill.
    Materialart: Digitale Medien
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  • 83
    Digitale Medien
    Digitale Medien
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 16 (1976), S. 15-24 
    ISSN: 0032-3888
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Articles with increased rigidity can be obtained by compression molding at high pressures as shown by experiments with five types of linear polyethylene. The materials, with weight average molecular weight ranging up to 1,000,000 were molded at pressures as high as 80,000 psi. The material temperature was 149-204°C, and the tooling was at 38°C. The duration of load was typically 3 mins, and the thickness of the molded disks was 12.7 mm. The results show that at high molding pressure the tensile modulus of the material is nearly twice that of materials molded conventionally at low pressures. This increase in modulus occurs for all the materials studied and even for a duration of load of only one min. The causes for this large increase in modulus were investigated with the help of density and melting point measurements and optical and electron microscopy. It was observed that the spherulites showed a distinctive and systematic change with the forming pressure. A hypothesis is proposed to explain the high modulus phenomenon on the basis of the kinetics of spherulite formation.
    Zusätzliches Material: 8 Ill.
    Materialart: Digitale Medien
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  • 84
    Digitale Medien
    Digitale Medien
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 16 (1976), S. 87-92 
    ISSN: 0032-3888
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Polymer blends and composites are composed of two different components, and usually, two different phases. Sometimes one phase is continuous and the other clearly discontinuous. Often, however, both phases retain some degree of continuity, as in certain fiber reinforced composites, block copolymers, materials composed of alternating lamellae structures and interpenetrating networks. A semi-empirical theory is developed to express mathematically not only the known structures, but also two-phase morphologies not yet synthesized or characterized. Many structures both real and proposed are shown to exhibit dual phase continuity, although for most systems, one phase can be said to be “more continuous” and the other “less continuous”.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
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  • 85
    Digitale Medien
    Digitale Medien
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 16 (1976), S. 82-86 
    ISSN: 0032-3888
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: For fabrication processes such as blow molding, vacuum forming, film blowing and fiber spinning, extensional flow is the dominate mode of melt deformation. Under these conditions, extensional viscosity is a significant rheological property. Thus, the biaxial extensional viscosity was measured for several samples of polypropylene. A technique based on the bubble inflation method of Denson and Gallo was used. Experimental values of biaxial extensional viscosities ranging from 1014 to 1010 poise as a function of strain rate, 10-5 to 10-2 reciprocal seconds, were obtained at 25°C. The technique used was critiqued and found to be useful in characterizing unoriented and biaxially oriented films, Uniaxially oriented films gave unsatisfactory results. It may be possible to use this testing method to assist in materials selection decisions.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
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  • 86
    Digitale Medien
    Digitale Medien
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 16 (1976), S. 138-144 
    ISSN: 0032-3888
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: This paper points out that interpretations from stress changes alone during oriented crystallization have led to widely different proposed chain conformations and consequently very different crystallization mechanisms for strain-induced crystallization (SIC). Many of the proposals, including the one by Keller and Machin which takes into account some electron microscopy and X-ray observations, show varying degrees of incompatibility with existing stress relaxation, kinetic or morphological data on SIC. Another problem lies in the difficulty with proper interpretation of observed morphology on samples which have been Subjected to additional thermally-induced crystallization (TIC) after SIC, especially, in the absence of prior characterization of SIC crystallites, the finding of a fibrillar-to-lamellar transformation in stretched polymers upon additional TIC (Part H) also indicates that the generally-observed oriented lamellar morphology has a much more subtle origin than-that depicted by most crystallization models. Part I discusses our previously published morphological data on the characteristics of SIC crystallites from the melt, which includes: (a) their melting point elevation, (Tm » T°m), (b) their nearly perfect crystalline orientation function (fc ∼ 1), (c) their fast rates of crystallization (t1/2 〈 1 sec), and (d) their fibrillar morphology and limited dimensions along the fibrillar stretch axis (∼100Å). Examples of morphology of SIC from the glass and from stirred solution are also included to show the overall similarity of fibrillar morphology brought about by stretching.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
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  • 87
    ISSN: 0032-3888
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Stress-induced crystallization may be studied by the birefringence technique and by low-angle light scattering. From measurements of the change in birefringence and stress during the crystallization of a polymer above its Tg and from a calculation of the intrinsic birefringence of a polymer crystal, the change in volume fraction crystallinity may be calculated. The technique is illustrated for several polymers and found to give values in reasonable agreement with other methods for the study of crystallinity. Crystallization is also accompanied by the development of a low-angle light scattering pattern, the size and shape of which is indicative of the amount, size and morphology of the crystalline superstructure.
    Zusätzliches Material: 12 Ill.
    Materialart: Digitale Medien
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  • 88
    Digitale Medien
    Digitale Medien
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 16 (1976), S. 158-162 
    ISSN: 0032-3888
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Several observations are made regarding the role of the fluid mechanics involved in the process of flow-induced, fibrillar crystallization from solution. Computational evaluation and discussion of various flow effects in the nucleation step, including combined shear and extensional flows, are presented in terms of the elastic dumbbell model. These results indicate the important role extensional kinematics in the growth process. A qualitative evaluation of concentration effects is also given. The evaluation of facts concerning the growth morphology is presented in terms of a model for the growth process along with data concerning rinsing and quench rate effects on the morphology and inciting behavior of shish kebab crystals.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
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  • 89
    Digitale Medien
    Digitale Medien
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 16 (1976), S. 168-175 
    ISSN: 0032-3888
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: A theory of crystallization under stress is developed about the premise that the direction a chain takes through a crystallite, relative to its end-to-end vector, is determined by the first few links of a chain that initially deposit onto the crystallite surface. Since these few links are quickly trapped by subsequently crystallizing chains, their orientational probability prior to deposition governs the chain direction through the crystallite, and the properties of the system depend upon a statistical distribution of all vector orientations. Such a model leads to a relationship between the melting temperature and the degree of network orientation, and relates the retractive force to temperature in the crystallization region. The theory appears to adequately describe some of the published data on rubber and polychloroprene networks.
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 90
    Digitale Medien
    Digitale Medien
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 16 (1976), S. 204-211 
    ISSN: 0032-3888
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: This study demonstrates that it is possible to extrude highly oriented polyethylene fibers using only a plasticating single screw extruder, specially designed and operated dies, and a simple take up mechanism. The degree of orientation achieved is as high as that achieved in solid state extrusion studies but accomplished at a fraction of the pressure. The degree of orientation is significantly greater than that of commercial grade fibers. The orientation is developed in the elongational flow of the “wine glass stem” region preceding the die entrance and is retained by crystallization in the die. Crystallization is inhibited in the pre-die region by maintaining a temperature above the effective melting point of the flowing, oriented (hence lowered entropy) melt.
    Zusätzliches Material: 15 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 91
    Digitale Medien
    Digitale Medien
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 16 (1976), S. 229-234 
    ISSN: 0032-3888
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: This article describes a new experimental and analytical method for determining the specific heat and thermal coductivity of plastic materials. This method arrives at these temperature-dependent properties by analyzing the thermal history of a slab of the plastic material. The procedure is as follows: 1) A partial differential equation model of the heat flow through the slab is established a priori. 2) A varying heat flux is a applied to the slab, and temperature readings throughout the plastic are recorded at fixed time intervals. 3) This temperature data is fed into a digital computer (along with the established mathematical model) and the required specific heat and thermal conductivity values are extracted. The extraction is done by using the maximum likelihood system identification technique.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 92
    Digitale Medien
    Digitale Medien
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 16 (1976), S. 240-245 
    ISSN: 0032-3888
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: A method is described to predict the time-temperature behavior and hence thermal stability of PVC melts in a Brabender Plasticorder torque rheometer from basic rheological data(flow and thermal stability observations) obtained on an Instron capillary rheormeter. The predicted and experimentally determined values of the Brabender thermal stability are shown to be in good agreement.
    Zusätzliches Material: 10 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 93
    Digitale Medien
    Digitale Medien
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 16 (1976) 
    ISSN: 0032-3888
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 94
    Digitale Medien
    Digitale Medien
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 16 (1976), S. 270-275 
    ISSN: 0032-3888
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: The inflation and growth kinetics of bubbles in thermoplastic structural foams are discussed in some detail using a model which assumes the initial existence of very small voids in the pressurized polymer melt. The effects of a drop in external pressure, the presence of a distribution of bubble sizes, and the diffusion of gas between neighboring bubbles are considered. It is shown that at a given pressure the number of growing bubbles present in the melt at any onetime depends on the ratio of the critical radius to the average radius of the microvoids assumed to be present in the melt It is also demonstrated that gas diffusion between neighboring bubbles reduces the growth rate appreciably only when the interbubble distance is reduced to a micron or less.
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 95
    Digitale Medien
    Digitale Medien
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 16 (1976), S. 276-283 
    ISSN: 0032-3888
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: This paper concerns the action of plasticizers and nucleating agents on the crystallization of bisphenol-A polycarbonate. The influence of plasticizers is to increase the rate of crystallization to a great extent using 10 percent of a plasticizer such as trimellitic acid, tridecyloctyl ester. The influence of nucleating substances on plasticized and undiluted polycarbonate is investigated. A large number of substances have been found capable of nucleating polycarbonate crystallization. The un-plasticized semi-crystalline polycarbonate is characterized by a much higher melting point (300°C) than the plasticized semi-crystalline systems (210-245°C). The stability of bisphenol-A polycarbonate in the presence of nucleating salts is also examined. We observe a substantial decrease in the molecular weight in the presence of a great number of nucleating substances. The modulus-temperature curves of two semi-crystalline polymers are reported in the last series of experiments.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 96
    Digitale Medien
    Digitale Medien
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 16 (1976), S. 294-297 
    ISSN: 0032-3888
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 97
    Digitale Medien
    Digitale Medien
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 16 (1976), S. 318-322 
    ISSN: 0032-3888
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Polyphenylquinoxalines (PPQ) were crosslinked with a tris-benzil comonomer, to alleviate the inherenthigh temperature thermoplasticity, and evaluated as matrices in graphite reinforced composites. The room temperature flexural strength/modulus of Modmor IJ laminates were as high as 245,000 psi/16,6 × 106 psi. Essentially 100 percent retention of ambient mechanical properties was obtained at 371°C using a PPQ matrix from the fully-crosslinked polymer prepared from 4,4′-bis(4″-oxybenzilyl) benzil (BOBB) and 3,3′-diaminQbenzrdine. The degree of high temperature thermoplasticity in the composite was found to be more closely related to the final postcure temperature than to the BOBB crosslink density. The thermoplasticity essentially disappeared when the BOBB comonomer-PPQ laminates were postcured at 482-510°C in nitrogen. Substitution of DMAC for the commonly used m-cresol solvent system allowed facile preparation of prepreg to fabricate low-void laminates and NOL rings.
    Zusätzliches Material: 5 Tab.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 98
    Digitale Medien
    Digitale Medien
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 16 (1976), S. 327-333 
    ISSN: 0032-3888
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: By combining quantitative molecular, microscopic and macroscopic information from an oriented crystalline polymer, it becomes possible to unify, predict, and explain not only processing behavior but such important material properties as failure, shrinkage, modulus, yielding, melting, and storage and loss moduli. Among the advantages gained by this approach are the ability to: (a) identify the particular phase of the two-phase system which controls a given property-(b) correlate internal structure quantitatively with a large number of seemingly different types of properties; (c) identify quantitative behavioral rules which are generally valid for Very different crystalline polymers; (d) clarify component roles such that new techniques and processes result; and (e) predict the properties of a crystalline polymer for structural states not previously tested. Using two dissimilar crystalline polymers, isotactic polypropylene and poly(ethylene terephthalate), as examples, the general validity and unifying power of the structural approaches is demonstrated.
    Zusätzliches Material: 16 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 99
    Digitale Medien
    Digitale Medien
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 16 (1976), S. 334-343 
    ISSN: 0032-3888
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Constitutive relationships are presented to relate the directional dependence of the mechanical properties of anisotropic, partially crystalline polymers to (a) the percent crystallinity, (b) characteristics of the crystalline and amorphous orientation distribution, and (c) the mechanical properties of the crystalline and amorphous components. These relationships were tested with structural and dynamic mechanical data obtained for isotactic polypropylene films in various states of crystalline and amorphous orientation. The dynamic mechanical properties of the crystalline and amorphous components were treated as parameters and evaluated from dynamic mechanical measurements along the longitudinal and transverse direction of three different film samples. These mechanical parameters, and the associated structural parameters, were in turn used to predict the dynamic mechanical spectra for a fourth, independent, film sample. The predicted values for the storage and loss modulus, along various directions of loading, were within 10 percent of the measured values over the temperature range of -80°C to 80°C.
    Zusätzliches Material: 8 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 100
    Digitale Medien
    Digitale Medien
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 16 (1976), S. 344-352 
    ISSN: 0032-3888
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: The Halpin-Tsai equations are based upon the “self-consistent micromechanics method” developed by Hill. Hermans employed this model to obtain a solution in terms of Hill's “reduced moduli”. Halpin and Tsai have reduced Hermans' solution to a simpler analytical form and extended its use for a variety of filament geometries. The development of these micromechanic's relationships, which form the operational bases for the coniposite analogy of Halpin and Kardos for semi-crystalline polymers, are reviewed herein.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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