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  • 1
    ISSN: 1618-2650
    Keywords: Nachw. von Amphetamin ; Catecholaminen ; Halluzinogenen ; Chromatographie ; Gas/Massenspektrometrie ; pg-Bereich
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Eine Reihe biologisch interessanter primärer Amine mit Phenyläthylamin-Struktur läßt sich in einer äußerst einfachen Reaktion in ihre Isothiocyanate überführen, wobei vorhandene Hydroxyle im gleichen Arbeitsgang silyliert werden können. Die Derivate lassen sich gut gas-chromatographieren. Sie liefern bei der Elektronenstoß-Ionisation meist nur wenige und dafür intensive Ionen, die sich als Tracer für die hochempfindliche massenspezifische Detektion der Verbindungen vorzüglich eignen. Arbeitet man mit niedriger Elektronenenergie (die von Fall zu Fall in Vorversuchen bestimmt werden muß), so ist das Molekül oft das Basision. Bei gleichzeitiger Erfassung seiner Isotopenionen kommt dem Verfahren eine besonders hohe Spezifität zu. Von den meisten der bestimmten Verbindungen konnten auf diesem Wege, d.h. mit GC-MD besonders ausgewählter Derivate, bis 10 pg noch erfaßt werden. Das Detektionssystem wäre allerdings in der Lage, sub-pg-Mengen zu sehen. Die Gas-Chromatographie wirkt jedoch infolge irreversibler Kolonnenadsorption so kleiner Mengen als beschränkender Faktor.
    Notes: Abstract Several biologically important primary amines with phenylethylamine structure can be converted in a very simple reaction to their isothiocyanates. Aromatic or aliphatic hydroxyl groups which may be present can be silylated in the same reaction step. The derivatives are much easier to separate by gas chromatography than their starting materials. On electron impact, they furnish only a few, intense ions which are ideal tracers for the mass specific gas chromatographic detection of the compounds. If a reduced electron energy is employed (which must be predetermined in each case), the molecular ions may often be the base ions. Simultaneous detection of their isotopic ions gives a gas chromatographic analysis of very high specificity. Using this approach (that is GC-MD analysis of specially chosen derivatives), most of the compounds tested could be detected down to the 10 pg-range. The mass detector would be able to measure sub-pg-quantities. However, the gas chromatograph is the limiting factor, since such small amounts are irreversibly adsorbed on the partition column.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 38 (1955), S. 1396-1398 
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The poisoning effect of hydroxy-s-triazines on Pt-catalyst was observed using the system PtO2, triazine-derivative, 3,4,5-trimethoxy-cinnamic acid and H2 in alcohol. The dihydroxy-s-triazines I and II resulting from alkaline oxidation of uric acid, their dihydro-derivatives III and IV, and trihydroxy-s-triazine cyanuric acid (VI) inhibit the hydrogenation as has previously been found for the unsubstituted s-triazine V.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 36 (1953), S. 549-554 
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: α,α′-Imino-glutaric-succ,inic acid is not decomposed by a highly purified preparation of glutamic-oxalacetic transaminase; „α,α'-iminoacid dehydrases“ must be different from transaminases.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 50 (1967), S. 958-962 
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Amphetamine (I) reacts spontaneously at room temperature with carbon disulfide to form (1-phenyl-isopropyl)-isothiocyanate, which was identified by UV.-, IR.- and mass spectrometry. This reaction is used for the analytical determination of I by gas chromatography. The characteristic peak shift which occurs after addition of carbon disulfide differentiates I from N-methylamphetamine (II). The method is applied to urine analysis of I and II (which partially metabolizes to I) and might be useful in doping control.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 50 (1967), S. 1409-1415 
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A flameless atomic absorption method for the determination of small amounts of mercury in solutions is described. The mercury is amalgamated quantitatively on a copper wire and subsequently vaporized in an absorption cell which is placed in the light path of a commercial atomic absorption instrument. The mercury vapor can be quantitatively determined by its absorption of the 253.7 nm mercury line. The method has a detection limit of 0.2 ng and is therefore about 10000 times more sensitive than atomic absorption analysis using flame atomization.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: After decaffeination of green coffee beans by extraction with [14C]-trichloroethylene, the beans were radioactive and did not loose their activity during roasting. On the basis of the radioactivity uptake, it is estimated that during commercial decaffeination 0.25 to 1 g of trichloroethylene is incorporated per kg of beans. The nature of the compound or compounds formed on interaction of trichloroethylene with coffee constituents is still unknown, but attention is directed to the possibility of the formation of highly toxic S-dichlorovinyl derivatives as is the case in the extraction of soya beans with trichloroethylene.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 34 (1951), S. 82-98 
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Es wurden verschiedene (stereoisomere) α,α′-Imino-propionsäureglutarsäuren, α,α′-Imino glutarsäuren,-bernsteinsäuren und α,α′-Imino glutarsäuren,-bernsteinsäuren hergestellt und ihr Verhalten zu Fermenten, die sich in Leber und Nieren finden, untersucht. Während sich in Nieren- und Leberhomogenaten und in Extrakten aus Aceton-Trockenpulver der genannten Organe keine Fermente nachweisen liessen, welche α,α′-Imino-dipropionsäuren, α,α′-Imino-propionsäureisocapronsäure, Octopin und α,α′-Imino-bernsteinsäure-propionsäuren dehydrieren, wurden α,α′-Imino-propionsäure-glutarsäuren (II) und α,α′-Imino-glutarsäure-bernsteinsäuren (III) bei Gegenwart der genannten Fermentsysteme durch Sauerstoff rasch dehydriert. Es scheint demnach, dass zur Angreifbarkeit solcher Imino-dicarbonsäuren durch Dehydrasen Glutaminsäure am Aufbau der Iminodicarbonsäure teilhaben muss. Als Folge der Hydrolyse der durch die Hydrierung gebildeten Schiff'schen Basen und nachfolgenden Desaminierung der gebildeten Aminosäuren wird Ammoniak freigesetzt, dessen Menge dem Sauerstoffverbrauch, d. h. der Dehydrierung parallel geht.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Diethyl ether is introduced as solvent for the analysis of gallium, indium and thallium by flame emission. Its use improves the analytical sensitivity and the detection limits of the method. Since diethyl ether is the solvent of choice for the extraction of the three metals from aqueous solutions, the possibility of spraying such extracts into the flame simplifies detection and assay. A procedure for the analysis of thallium in biological samples is given and illustrated by figures for its distribution in a man poisoned by a fatal dose of thallium sulphate.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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