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  • 1
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    STUTTGART U. A.: THIEME
    Call number: 03-B:52
    Keywords: Nahrungsmittel / Zusatz
    Pages: VIII, 220 S., ILL., TAB.
    ISBN: 3-13-687101-4
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    03-B:52 departmental collection or stack – please contact the library
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  • 2
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    Weinheim, Germany : WILEY-VCH Verlag GmbH & Co. KGaA
    Keywords: Chemistry, Analytic
    Notes: Electronic reproduction. Ann Arbor, MI : ProQuest, 2016. Available via World Wide Web. Access may be limited to ProQuest affiliated libraries.
    Pages: 1 online resource (563 pages) : color illustrations.
    Edition: Dritte, überarbeitete und aktualisierte Auflage.
    ISBN: 9783527698790
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  • 3
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    Stuttgart : Thieme
    Call number: 01-SichIng:177
    Keywords: Chemie / Analyse
    Pages: vii, 234 p.
    ISBN: 3-13-759301-8
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    01-SichIng:177 departmental collection or stack – please contact the library
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  • 4
    ISSN: 1432-1130
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract  The integration of an urease reactor into a gas diffusion flow injection system was investigated for the determination of urease inhibitors. The enzyme was immobilized by entrapping in polyacrylamide gel. Besides copper and silver ions mercury ions inhibit the conversion of urea to carbon dioxide and ammonia catalysed by urease. The pH change of the carrier solution caused by the ammonia released was measured potentiometrically with a pH electrode. The inhibition behaviour of Hg(II) ions was investigated. A linear range from 2 to 20 μg L-1 Hg(II) was obtained after a 90 s inhibition, with a correlation coefficient of r=0.9997. The relative standard deviation was 1.4% for five measurements of 2 μg L-1Hg(II). A sample frequency of 7 h-1 was achieved. The inhibited enzyme can be reactivated. The method was applied to the determination of Hg(II) in two drinking water samples.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1618-2650
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The hydrolytic stability of organophosphonic acids, comprising 〉NCH2PO3H2 moieties, is studied exemplarily on aqueous solutions of ethylenediaminetetramethylenephosphonic acid (EDTMP). Metabolization of EDTMP increases severely at lower pH values, and is enhanced at higher temperature. The formation of orthophosphate in the course of the hydrolytical degradation can be established unequivocally by several, methodologically independent analytical procedures. By ion chromatography, the presence of (inorganic) phosphonate (phosphite) is affirmed in alkaline, and of hydroxymethylphosphonate in neutral to acid solutions. Formation of all three metabolites is in accord with a general degradation mechanism proposed here. The results of these stability investigations have far-reaching consequences for the analytical practice, as well as for the industrial application of organophosphonic acids.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1618-2650
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The ion-chromatographic separation of organophosphonic acids is investigated systematically in a comparative study of two anion-exchange resins (Dionex HPIC AS7, Biotronik BT I AN). For thirteen structurally diverse phosphonic acids, chromatographic properties are determined with HNO3 eluents (5–30 mmol/l), and compared with those of classical complexones and inorganic anions, e.g. phosphonate (phosphite) and phosphate. While all anions tested may be determined, in principle, both qualitatively and quantitatively (down to a 10 ppm scale) on the two materials, the Dionex column exhibits the far higher separation potential and can be applied to almost any analytical problem in the phosphonic acid field. A systematic optimization of the separation conditions for the Dionex HPIC AS7 (a detailed prescription is given) makes qualitative and quantitative analyses possible which hitherto could not be performed with this material.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 0941-1216
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Characterization of Some Species of Wood by HPCL Analysis of Ethanolic ExtractsLignin degradation products of ethanolic wood extracts were separated by liquid chromatography and quantified by UV and electrochemical detection. The identification of eight analysed compounds was carried out by comparing their UV absorption spectra and the retention times with those of reference substances. The characteristic composition of the extracts was determined for eight different species of wood. The extraction parameters of temperature and time and also effects of prelimary thermical treatment and hydrolysis by trifluoracetic acid were investigated.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 0941-1216
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Goethe and the Earlier Chemical JournalsTwo hundred years ago the german “Allgemeines Journal der Chemie” was founded by the Bergrat Scherer from Weimar. His redaction was situated in the castle Belvedere. Goethe was a promoter of this chemist und editor. The concept of this journal, the citations of Goethe and his works in the following “Journal für Chemie und Physik”, edited by Schweigger, and the interests of Goethe as reader also on Crells oldest chemical journal from 1778 are described in detail.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 1618-2650
    Keywords: Best. von Thallium, Selen, Tellur, Quecksilber, Arsen, Antimon, Wismut, Zinn ; Chromatographie, Gas ; Abtrenn. als Phenylverbindung
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Die Phenylverbindungen von Thallium, Selen, Tellur, Quecksilber, Arsen, Antimon, Wismut und Zinn sind zur gas-chromatographischen Analyse dieser Elemente geeignet. Sie entstehen bis auf Thalliumtriphenyl quantitativ beim Umsatz der aus saurer Lösung extrahierten Diäthyldithiocarbamidate mit magnesiumorganischen Verbindungen. Gas-chromatographisch lassen sich die Phenylverbindungen aller acht Elemente mit einer Säule unter Verwendung eines Temperaturprogramms trennen. Im Falle des Quecksilberdiphenyls konnte keine vollständige Elution erreicht werden.
    Notes: Abstract The phenyl compounds of thallium, selenium, tellurium, mercury, arsenic, antimony, bismuth and tin are suitable for the analysis of these elements by gas chromatography. They are produced quantitatively except thallium triphenyl when the diethyldithiocarbamates, which are extracted out of acid solution, are reacted with magnesium organic compounds. By gas chromatography the phenyl compounds of all eight elements are separated with one column by utilizing a temperature program. In case of mercury diphenyl complete elution could not be realized.
    Type of Medium: Electronic Resource
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  • 10
    ISSN: 1618-2650
    Keywords: Best. von Adrenalin, Noradrenalin, 3,4-Dihydroxyphenylalanin ; Fluorimetrie ; automat., Selektivitätseffekte
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Adrenalin, Noradrenalin, 3,4-Dihydroxyphenylalanin (Dopa) und die Summe Adrenalin + Noradrenalin als Gesamtkatecholamine lassen sich automatisch-fluorimetrisch in einem Analysensystem (nach Wisser) nach der Trihydroxyindolmethode bestimmen. Die Fluorescenzausbeuten für die Fluorophore der einzelnen Verbindungen sind außer bei der differenzierten Adrenalinbestimmung von der Pumpengeschwindigkeit des Autoanalyzers abhängig. Durch diese Unterschiede ergeben sich Selektivitätseffekte für die Bestimmung von Dopa neben Noradrenalin und von Adrenalin neben Noradrenalin. Ebenso wurde der Einfluß der Ansaugzeit auf die Fluorescenzausbeute untersucht. Die optimalen Einstellungen für die einzelnen Bestimmungsmethoden werden angegeben.
    Notes: Abstract Adrenaline, noradrenaline, 3,4-dihydroxyphenylalanine (Dopa) and adrenaline plus noradrenaline as total catecholamines can automaticallyfluorimetrically be determined in one analysis system (according to Wisser) by the trihydroxyindole method. The fluorescence yields for the fluorophores of the single compounds are dependent on the pump speed of the autoanalyzer except for the differentiated determination of adrenaline. Caused by these differences effects of selectivity are demonstrated for the determination of Dopa disturbed by noradrenaline and adrenaline disturbed by noradrenaline. Also the influence of the suction time on the fluorescence yield was investigated. The optimal adjustings for the single methods of determination are given.
    Type of Medium: Electronic Resource
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