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  • 1
    Electronic Resource
    Electronic Resource
    Solution equilibria in l-glutamic acid and l-serine + iron(III) systems (1997)
    Springer
    Transition metal chemistry 22 (1997), S. 284-293 
    Details
    ISSN: 1572-901X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Complex formation equilibria in l-glutamic acid (H2Glu) and l-serine (HSer) +iron(III) ion systems have been studied by a combination of glass electrode potentiometric and visible spectrophotometric measurements in 0.5 mol dm–3 (Na)NO3 ionic medium at 25°C. In the concentration range 1.0≤[Fe3+]≤5.0; 3.0≤[Glu2−]≤30.0 mmol dm−3 ([Glu]/[Fe]=3:1 to 30:1) and pH between 1.5 and 4.5, iron(III) and glutamic acid form the Fe(Glu)−2, Fe(Glu)+, Fe(HGlu)2+, Fe(OH)Glu, Fe2(OH)2Glu2+, Fe(OH)Glu22− complexes: and several pure hydrolytic products. Iron(III) and l-serine, beside pure hydrolytic complexes of iron(III), form the Fe(HSer)3+, Fe(Ser)2+, Fe(OH)Ser+, Fe(OH)2- Ser0, Fe(OH)Ser2 and Fe2(OH)2(Ser)2+2 complexes, over a broad concentration range of serine to iron ([Ser]/[Fe]=5:1 to 500:1), from pH 1.5 to 4.0. The stability constants of the complexes are given and their formation mechanism is suggested. The possible structure of the complexes, in solution, is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1018476810838
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  • 2
    Electronic Resource
    Electronic Resource
    Complex formation equilibria in iron(III)-L-alanine system (1993)
    Springer
    Transition metal chemistry 18 (1993), S. 457-461 
    Details
    ISSN: 1572-901X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Complex formation in iron(III)-L-alanine solutions was studied by emf glass electrode and spectrophotometric measurements, in 0.5 mol dm −3 (Na)NO3 medium, at 25 ° C. In the concentration range 0.5 ⩽ [Fe]0 ⩽ 20.0, 5.0 ⩽ [Ala]0 ⩽ 1000.0 (mmol dm−3) and 1.0 ⩽ -log [H+] ⩽ 3.5; {[Ala]/[Fe] = 10:1-100:1| the equilibria in the title system were explained by the model including the species FeHL, FeL, Fe(OH)L, Fe2(OH)2L2 (where HL denotes L-alanine) and several hydrolytic products. The stability constants of complexes are given. The mechanism of formation and structure of complexes in solution is proposed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00136603
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  • 3
    Electronic Resource
    Electronic Resource
    Determination of pefloxacin in serum and pharmaceutical forms by derivative spectrophotometry (1997)
    Springer
    Microchimica acta 126 (1997), S. 203-206 
    Details
    ISSN: 1436-5073
    Keywords: pefloxacin ; serum ; pharmaceutical forms ; derivative spectrophotometry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract A method for the direct determination of pefloxacin in serum and pharmaceutical forms (tablets and ampoules) has been developed, based on the use of second-order derivative ultraviolet spectra. Spectrophotometric assay of pefloxacin in tablets and ampoules was carried out in 0.1 mol/L NaOH, while in serum it was performed in 0.1 mol/L NaOH with the addition of sodium dodecylsulfate, in 337–347 nm wavelength range. Linear calibration curves were obtained in the concentration ranges 2–30μg/mL pefloxacin for tablets and ampoules and 0.12–5 μg/ mL for serum samples. Relative error of determination, as criterion for accuracy, was less than 1%, while the precision was better than 4 ng/ml. The minimum detectable concentration of pefloxacin in serum was 15 ng/mL.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01242321
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  • 4
    Electronic Resource
    Electronic Resource
    Study of Equilibria in the Aluminium(III)-Glycine and -Alanine Systems (1989)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 575 (1989), S. 217-228 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Untersuchung der Gleichgewichte in den Aluminium (III)-Glycin- und -Alanin-SystemenDie Bildung verschiedener basischer und gemischt-basischer Komplexe des AlIII-Ions in Gegenwart von Glycin und L-Alanin wurde 0,5 mol dm-3 (Na)NO3-Medium bei 25°C mittels EMK untersucht. Die Konzentration von Aminosäure zu AlIII wurden von 1 : 1 bis 10 : 1 variiert. Die durch die Anwendung der Methode der kleinsten Quadrate erhaltenen Daten weisen in Abwesenheit der Aminosäuren auf die Bildung des Dimeren [Al2(OH)2]4+ und Monomeren [AlOH]2+ mit den Stabilitätskonstanten log β22 = -7,03 ± 0,03 bzw. log β11 = -5,65 ± 0,09. Bei pH-Werten höher als ∼4,0 wird die Bildung des Trimeren [Al3(OH)4]5+ (log β34 = -12,60 ± 0,08) deutlich. In Gegenwart der Aminosäuren wurde der Hinweis auf die Bildung von [Al2(OH)4]2+ (log β24 = -15,65 ± 0,09) gefunden. Neben der Bildung der reinen basischen Komplexe können die im Titel genannten Gleichgewichte unter der Annahme von [Al(OH)3Gly] (log β131 = -7,53 ± 0,04), [Al2(OH)2(Gly)2] (log β222 = 6,56 ± 0.09) und [Al(OH)3Ala] (log β131 = -7,70 ± 0,03), [Al2(OH)2(Ala)2] (log β222 = 7,23 ± 0,07) als Hauptreaktionsprodukte erklärt werden.
    Notes: The formation of various hydrolytic and mixed hydrolytic complexes of the aluminium(III) ion in the presence of glycine and L-alanine, has been studied in 0.5 mol dm-3 (Na)NO3 medium at 25deg;C, by emf method. The concentration ratios of amine acids to aluminium(III) were varied from 1 : 1 to 10 : 1. The least-squares treatment of the data obtained, in the absence of the amino acids, indicates the formation of the dimer, [Al2(OH)2]4+, and monomer, [AlOH]2+, with the stability constants log β22 = -7.03 ± 0.03 and log β11 = -5.65 ± 0.09, respectively. At pH values higher then ∼4.0 formation of the trimer [Al3(OH)4]5+ (log β34 = -12.60 ± 0.08) becomes significant. In the presence of amino acids the evidence has been found for the formation of [Al2(OH)4]2+ (log β24 = -15.65 ± 0.09). Besides the formation of the pure hydrolytic complexes, equilibria in the title systems can be explained by assuming the main reaction products to have the compositions [Al(OH)3Gly] (log β131 = -7.53 ± 0.04), [Al2(OH)2(Gly)2] (log β222 = 6.56 ± 0.09) and [Al(OH)3Ala] (log β131 = -7.70 ± 0.03), [Al2(OH)2Ala2] (log β222 = 7.23 ± 0.07).
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19895750126
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  • 5
    Electronic Resource
    Electronic Resource
    Effect of acetate and EDTA ligands on Hydrolysis of the Iron(III) Ion in sodium chloride medium (1989)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 571 (1989), S. 174-180 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Einfluß von Acetat- und EDTA-Liganden auf die Hydrolyse des Eisen(III)-Ions in Natriumchlorid-haltigem MediumDie Hydrolyse des Eisen(III)-Ions in Natriumchlorid-haltigem Medium frei von organischen Liganden und in Gegenwart von Acetat bzw. EDTA wurde mittels der EMK-Methode bei 25°C untersucht. Die Ergebnisse weisen auf einen Einfluß der organischen Liganden. In Gegenwart des Acetations wird der Beginn der Hydrolyse zu etwas niedrigerem pH verschoben, während in Gegenwart von EDTA, einem starken Komplexbildner, sich der Beginn der Hydrolyse um 2,5 Einheiten zu höherem pH verschiebt.
    Notes: The hydrolysis of the iron(III) ion in sodium chloride medium without organic ligands and in the presence of acetate and EDTA ligands was studied by emf method, at 25°C. The data indicate the effect of the organic ligands. In the presence of acetate ion the beginning of hydrolysis of the iron(III) ion is slightly shifted toward lower pH values, while in the presence of EDTA, as a strong complex forming ligand, the beginning of hydrolysis is shifted toward higher pH values for 2.5 pH units.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19895710120
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