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  • 1
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 10 (1987), S. 6-11 
    ISSN: 0935-6304
    Keywords: Capillary gas chromatography ; Negative ion mass spectrometry ; Plasma ; Estrone ; equilin ; Conjugated estrogens ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A procedure is described for the analysis of the estrogens equilin and estrone in human plasma following oral administration of conjugated estrogen preparations. After enzymatic hydrolysis of the sulfate conjugates, plasma proteins are precipitated with methanol and the estrogens extracted into ethyl acetate. Derivatization with the reagent flophemesylamine converts equilin and estrone into volatile pentafluorophenyldimethylsilyl ethers ideally suited to capillary gas chromatography-negative ion chemical ionization mass spectrometry. Using a 15 meter dimethyl silicone bonded phase fused silica capillary column separation of the estrone and equilin derivatives is achieved within 9 minutes. Selected ion monitoring of the intense negative molecular ions enables levels of 1 ng.ml-1 to be measured with coefficients of variation of 9.3 % and 14.2 % for estrone and equilin respectively. Plasma levels of the compounds are reported in two male volunteers up to 24 hours after dosing with 5 milligrams of Premarin™. (™ Ayerst Laboratories Inc., New York, USA.).
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 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.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A method has been developed for single ion monitoring of diphenylhydantoin and its major metabolite 5-(p-hydroxyphenyl)-5-phenylhydantoin in plasma. A plasma extract is reacted with N, O-bis(trimethylsilyl)acetamide and single ion recording is carried out using a gas chromatograph mass spectrometer system. The mass value selected, m/e 254, is common to the TMS ethers of diphenylhydantoin and its principal metabolite 5-(p-hydroxyphenyl)-5-phenylhydantoin. The results indicate that one cause of an adverse reaction to diphenylhydantoin could be a reduced ability to hydroxylate the drug. Quantitative methods for the analysis of the drug and its major metabolite have also been developed. Diphenylhydantoin and 5-(p-hydroxyphenyl)-5-phenylhydantoin can be analysed in plasma after addition of deuterium labelled internal standards and conversion to volatile derivatives for mass fragmentographic analysis. Diphenylhydantoin and its internal standard are analysed as the N, N-dimethyl derivative, and the hydroxylated metabolite and its internal standard are converted to a pertrimetylsilyl compound by reaction with N, O-bis-(trimethylsilyl)acetamide.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 2 (1975), S. 304-306 
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The identification of 6-methoxy 8-aminoquinoline as a metabolite of Primaquine, an important antimalarial drug, is described. The metabolite is present in urine, plasma and erythrocytes following drug ingestion. It was identified by mass fragmentography of its 1H and 2H acetate and the acetate produced from authentic material. No evidence of further metabolites was obtained.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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