| Autor: |
Georgieva, Stela, Nedeltcheva, Tsvetanka, Vladimirova, Latinka, Stoyanova-Ivanova, Angelina |
| Zdroj: |
Central European Journal of Chemistry; Mar2013, Vol. 11 Issue 3, p381-387, 7p |
| Abstrakt: |
Detailed investigations on the possibility for determination of the oxygen stoichiometry in YBaCuO superconducting samples by measuring the absorbance of the colored Co(III)-EDTA and Cu(II)-EDTA complexes in one solution have been performed. The absorptivity of the complexes at pH 2.5 and 4.9 as well as Beer's law have been studied. The content of the solution for the sample dissolving has been established. The stoichiometry of the oxidation-reduction reaction between Cu(III) from the sample and Co(II) in the solution has been proved. The possibility to dissolve the sample in air has been tested. As a result a simple and rapid spectrophotometric method for the determination of the δ non-stoichiometric oxygen coefficient in YBaCuO samples has been developed without precise measurement of the sample mass. The standard deviation of the δ- and y-coefficient results is 0.017. The reproducibility of the y-values in relative units (s) is 0.2%. The accuracy of the results has been confirmed by the method, which is based on the absorbance measurement of the I-starch compound. Graphical abstract: [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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