| Autor: |
M. Tomašković, Ernö Pretsch, J. Bendl, Z. Cimerman, Z. Štefanac |
| Rok vydání: |
1982 |
| Předmět: |
|
| Zdroj: |
Microchemical Journal. 27:372-379 |
| ISSN: |
0026-265X |
| DOI: |
10.1016/0026-265x(82)90026-1 |
| Popis: |
The study of D(−)-ribose complexing with calcium in aqueous solutions less than 1.64 × 10 −1 M by potentiometric measurements with a calcium selective electrode afforded the value of K 1 = 1.70 liters × mole −1 (SD = 1.05 × 10 −3 ). Numerical analysis indicated that complex species with 1:1 and 1:2 calcium to D(-)-ribose ratios are present simultaneously: k 1 = 1.13 liters × mole −1 and K 2 = 8.47 liters × mole −1 (SD = 0.95 × 10 −3 ). In methanolic medium 1.24 × 10 −2 M with regard to calcium chloride both stoichiometric proportions were evidenced. A large error accompanying the stability constant K 1 = 28 kg × mole −1 (RSD = 82%) renders unreasonable the K 2 value obtained from the product K 1 × K 2 = 96.5 kg 2 × mole −2 . The results are discussed with respect to the data published for more concentrated (1.27 M ) aqueous solutions obtained on the basis of 1 H-NMR spectroscopic investigations. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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