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  • 11
    Electronic Resource
    Electronic Resource
    Spectrophotometric determination of isonicotinic acid hydrazide (1966)
    Springer
    Microchimica acta 54 (1966), S. 513-517 
    Details
    ISSN: 1436-5073
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Isonikotinsäurehydrazid reagiert mit 2,3,5-Triphenyltetrazoliumchlorid in saurem Milieu bei Gegenwart von überschüssigem Thallium(III) unter Bildung eines rosa gefärbten Formazans mit dem Absorptionsmaximum bei 480 nm. Diese Farbreaktion wird zur Bestimmung von Isonikotinsäurehydrazid in Harn und Blut verwendet. Sie ist spezifisch. Ihre Erfassungsgrenze beträgt 1μg/ml.
    Abstract: Résumé L'hydrazide de l'acide isonicotinique réagit avec le chlorure de triphényl-2,3,5 tétrazolium, en milieu acide en présence d'un excès de thallium-III, en donnant un formazan coloré en rose dont le maximum d'absorption se situe à 480 nm. On utilise cette réaction colorée pour doser l'hydrazide de l'acide isonicotinique dans l'urine et dans le sang. La réaction est spécifique et la limite d'identification visuelle est de 1μg par ml.
    Notes: Summary Isonicotinic acid hydrazide reacts with 2,3,5-triphenyltetrazolium chloride in acidic medium in presence of excess of thallium(III) to give a pink-coloured formazan having maximum absorption at 480 nm. This colour reaction is used to determine isonicotinic acid hydrazide in urine and blood. The reaction is specific for isonicotinic acid hydrazide, and the visual limit of identification is1 μg per ml.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01219363
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  • 12
    Electronic Resource
    Electronic Resource
    Spectrophotometric determination of nitrogen in small quantities of biological materials (1968)
    Springer
    Microchimica acta 56 (1968), S. 860-865 
    Details
    ISSN: 1436-5073
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Eine neue Tüpfelreaktion auf Ammonium wurde beschrieben, die auf der Umsetzung mit Rutheniumtrichlorid-Triphenylphosphin beruht. Die Erfassungsgrenze beträgt 1μg. Mit Hilfe dieser Reaktion lassen sich kleinste Mengen Ammoniumstickstoff spektrophotometrisch in biologischem Material bestimmen.
    Notes: Summary A new spot test for ammonium, by its reaction with ruthenium trichloride-triphenylphosphine, having a Iμg limit of identification is reported. On the basis of this spot reaction a spectrophotometric method is described for the determination of minute quantities of NH4-N from biological materials.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01216930
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  • 13
    Electronic Resource
    Electronic Resource
    Ring test for ferrous ions (1968)
    Springer
    Microchimica acta 56 (1968), S. 705-707 
    Details
    ISSN: 1436-5073
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Überschichtet man eine wäßrige Lösung von Pantothensäure, Ascorbinsäure und Eisen(II) mit Äthylalkohol, so entsteht an der Berührungsstelle der beiden flüssigen Phasen ein blauer Ring, der für Eisen (II) charakteristisch ist. Die Nachweisgrenze beträgt 25μ Fe(II)/ml. Für verschiedene störende Metallionen wird die maximal tolerierbare Menge angegeben.
    Notes: Summary When ethyl alcohol is added to an aqueous solution containing small amount of pantothenic acid, ascorbic acid and Fe(II), beautiful blue ring is formed at the junction of ethyl alcohol-water which is characteristic of ferrous ions. The visual limit of identification is 25μ per ml of Fe(II). The maximum tolerable limit of various metal ions which do not interfere with the formation of blue ring is reported.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01216907
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  • 14
    Electronic Resource
    Electronic Resource
    Semiquantitative determination of micro amounts of iron, copper, cobalt, nickel, and zinc in blood and tissue by circular thin-layer chromatography (1968)
    Springer
    Microchimica acta 56 (1968), S. 712-718 
    Details
    ISSN: 1436-5073
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Ein halbquantitatives Verfahren zur Bestimmung von Eisen, Kupfer, Kobalt, Nickel und Zink auf dünnschicht-ringchromatographischem Wege wurde beschrieben. Der Fehler wurde auf ±5% eingeschränkt und die störende Wirkung von etwa 40 Metallionen durch Lösungsmittelextraktion beseitigt. Die Anwendbarkeit des Verfahrens für die Bestimmung in menschlichem Blut und Gewebe wurde gezeigt bzw. für die Untersuchung atmosphärischer Verunreinigungen empfohlen.
    Notes: Summary A semiquantitative method for the determination of iron, copper, cobalt, nickel and zinc is described which is based on circular thin-layer chromatographic technique. The error is minimized to ± 5% and interference of about 40 metal ions is removed by solvent extraction. The application of the method has been demonstrated by the determination of these metal ions in human blood and tissue and the method is suggested for the study of airborne particulates.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01216909
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  • 15
    Electronic Resource
    Electronic Resource
    Interaction of Zn2+ with the donor side of Photosystem II (1991)
    Springer
    Photosynthesis research 30 (1991), S. 123-130 
    Details
    ISSN: 1573-5079
    Keywords: oxygen evolution ; calcium ; chloride ; electron transport ; photosynthetic inhibitors
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The inhibitory effect of Zn2+ on photosynthetic electron transport was investigated in native and CaCl2-treated (depleted in extrinsic polypeptides) Photosystem II (PS II) submembrane preparations. Inhibition of 2,6-dichlorophenolindophenol photoreduction by Zn2+ was much stronger in protein-depleted preparations in comparison to the native form. It was found that Ca2+ significantly reduced the inhibition in the native PS II preparations, as did Mn2+ in a combination with H2O2 in the protein-depleted counterparts. No other tested monovalent or divalent cations could replace Ca2+ or Mn2+ in the respective experiments. Diphenylcarbazide could partially relieve (40–45%) the inhibition in both types of preparations. The above indicates the presence of an active Zn2+ inhibitory site on the donor side of PS II. However, neither Ca2+ nor Mn2+ could completely prevent inhibition by high concentrations of Zn2+ (〉1 mM). We propose that elevated levels of Zn2+ strongly perturb the conformation of the PS II core complex and might also affect the acceptor side of the photosystem.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00042010
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  • 16
    Electronic Resource
    Electronic Resource
    The 16 and 23 kDa extrinsic polypeptides and the associated Ca2+ and Cl- modify atrazine interaction with the photosystem II core complex (1990)
    Springer
    Photosynthesis research 24 (1990), S. 221-227 
    Details
    ISSN: 1573-5079
    Keywords: atrazine ; calcium ; chloride ; depleted-photosystem II ; DCIP-photoreduction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The oxygen evolving complex of photosystem II (PS II) contains three extrinsic polypeptides of approximate molecular weights 16, 23 and 33 kDa. These polypeptides are associated with the roles of Cl-, Ca2+ and Mn2+ in oxygen evolution. We have shown that selective removal of 16 and 23 kDa polypeptides from the above complex by NaCl washing of PS II enriched membrane fragments renders the PS II core complex more susceptible to the herbicide atrazine. On the other hand, when both native and depleted preparations were resupplied with exogenous Ca2+ and Cl-, we obtained a reduction of atrazine inhibition which was much stronger in the depleted preparations than in the native ones. It is concluded that removal of 16 and 23 kDa polypeptides in general, and disorganization of associated Ca2+ and Cl- in particular, enhances atrazine penetration to its sites of action in the vicinity of the PS II complex. The above could be interpreted if we assume a reduced plastoquinone affinity at the QB (secondary plastoquinone electron acceptor) pocket of D1 polypeptide following transmembranous modifications caused by the depletion of these polypeptides.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00032309
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