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  • 1
    Electronic Resource
    Electronic Resource
    Determination of niobium(V) with 5,7-diiodo-8-hydroxyquinoline (1982)
    Springer
    Monatshefte für Chemie 113 (1982), S. 307-311 
    Details
    ISSN: 1434-4475
    Keywords: Niobium, determination ; Spectrophotometry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Die Bestimmung von Niob(V) mit 5,7-Diiod-8-hydroxychinolin wurde in zitronensaurem Medium untersucht. Das Absorptionsmaximum liegt bei 425 nm (ε=4853 l mol−1 cm−1) bei einempH von 6,0. Der Einfluß der Erwärmungsperiode bei der Komplexbildung (Temperatur, Zeit) wurde untersucht, außerdem nochpH, Reagenskonzentration und weitere Variable. DasBeer'sche Gesetz ist über den untersuchten Bereich voll gültig. Der optimalste Bereich für eine Messung in 10 mm Küvetten liegt bei 10–12 µg Nb(V). Ein Metall: Ligand-Verhältnis von 1:2 wurde mit derJob-Methode und der Mol-Verhältnis-Methode überprüft.
    Notes: Abstract The determination of niobium with the reagent 5,7-diiodo-8-hydroxy-quinoline was studied spectrophotometrically in citric acid medium. The complex has absorption maximum at 435 nm (ε=4853 l mol−1 cm−1) with thepH6.0. The effects of heating temperature, time,pH, reagent concentration and other variables have been studied. The system confirms theBeer's law over the concentration range investigated. The optimum condition range for the measurement in 10 mm cells is 10–12 µg of niobium(V). The metal and ligand ratio of 1:2 was confirmed byJob's continuous variations and mole ratio methods.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00799557
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  • 2
    Electronic Resource
    Electronic Resource
    Spektrophotometrische Bestimmung von Tantal(V) mit 8-Hydroxychinolin-5-sulfonsäure (1975)
    Springer
    Monatshefte für Chemie 106 (1975), S. 695-699 
    Details
    ISSN: 1434-4475
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The formation of a yellow complex by the reaction between Ta(V) and 8-hydroxyquinoline-5-sulphonic acid (HQSA), has been studied spectrophotometrically in aqueous medium. At pH 6.5 the complex shows the maximum absorbance at 420 nm. TheBeer's law is obeyed by the system within the concentration range of 1 mg to 6 mg per millilitre of Ta(V). The stoichiometry of the complex determined by the mole ratio andJob's method is 1∶2 metal-ligand. The effect of ionic strength and temperature on chelate has been studied. The interference by various ions in the system and a probable structure of the complex are also suggested.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00902174
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Spectrophotometric determination of niobium in steel by means of p-sulphobenzeneazo-4-(2,3-dihydroxypyridine) (1981)
    Springer
    Fresenius' Zeitschrift für analytische Chemie 306 (1981), S. 401-401 
    Details
    ISSN: 1618-2650
    Keywords: Best. von Niob in Stahl ; Spektralphotometrie ; Sulfobenzolazodihydroxypyridin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00468657
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  • 4
    Electronic Resource
    Electronic Resource
    A sensitive spectrophotometric determination of niobium(V) with the reagent 5-chloro-8-hydroxy-7-iodoquinoline (1982)
    Springer
    Microchimica acta 78 (1982), S. 297-303 
    Details
    ISSN: 1436-5073
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Die Bestimmung von Niob in der Größenordnung von 0,02% und darüber ist in der Stahlanalyse nötig. Ein Verfahren zur Bestimmung von Mikrogrammengen Niob in rostfreien Stählen mit 5-Chlor-8-hydroxy-7-jodchinolin in zitronensaurem Medium wurde ausgearbeitet. Der Einfluß von Temperatur, Zeit, pH, Reagenskonzentration u. a. wurde untersucht. In dem angegebenen Bereich folgt die Reaktion dem Beerschen Gesetz. Bei Verwendung von 10-mm-Küvetten ist die Menge von 1,0–10,0μg/ml optimal. Die molare Absorptivität des Komplexes beträgt 5,143 x 10,03l·mol−1·cm−1. Fremdioneneinflüsse wurden untersucht. Die Stöchiometrie des Komplexes (Metall:Ligand=1∶2) wurde bestätigt.
    Notes: Summary The determination of niobium at levels of 0.02% and above is required in certain types of stainless steels and niobium stabilized steels. A method has been developed for the determination of microgram amounts of niobium in stainless steels with the reagent 5-chloro-8-hydroxy-7-iodoquinoline in citric acid medium. The effects of heating time, pH, reagent concentration and other variables have been studied. The system obeyes Beer's law over the concentration range investigated. The optimum concentration range for measurements in 10-mm cells is 1.0–10.0μg of niobium ml−1. The molar absorptivity of the complex is 5.143 x 103l·moli−1·cm−1. The interferences from foreign ions have been evaluated. The stoichiometry of the complex ML2 (metal:ligand) was confirmed by Job's continuous variations and mole ratio methods.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01206932
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  • 5
    Electronic Resource
    Electronic Resource
    Spectrophotometric determination of vanadium(V) with p-Sulphobenzeneazo-4-(2-amino-3-hydroxypyridine) (1982)
    Springer
    Microchimica acta 78 (1982), S. 305-310 
    Details
    ISSN: 1436-5073
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung p-Sulfobenzolazo-4-(2-amino-3-hydroxypyridin) bildet mit Vanadin(V) einen orange-roten Komplex, dessen Absorptionsmaximum bei 530 nm liegt. Bei Zimmertemperatur verläuft die Reaktion langsam, bei 40–45° ist sie in 5 min vollständig. Der Einfluß von Temperatur, Zeit, pH, Reagenskonzentration und anderer variabler Faktoren wurde untersucht. Im Konzentrationsbereich 1–12μg Vanadin/ml entspricht die Reaktion dem Beer-schen Gesetz. Die molare Absorptivität ist 5,453 x 103l·mol−1·cm−1. Das Verhältnis Metall:Ligand wurde nach Job bestimmt und beträgt 1∶2.
    Notes: Summary p-Sulphobenzeneazo-4-(2-amino-3-hydroxypyridine) reacts with vanadium to form an orange-red coloured complex having maximum absorbance at 530 nm. The reaction is slow at room temperature, it is complete at 40–45° C in 5 min. The effects of temperature, time, pH, reagent concentration, and other variables have been studied. The system obeys Beer's law over the concentration range of 1–12μg vanadium(V) ml−1. The molar absorptivity is 5.453 x 103l·mole−1·cm−1. The metal:ligand ratio of 1∶2 was confirmed by Job's continuous variation and mole ratio methods.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01206933
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