| Autor: |
Meloun, Milan, Ferenčíková, Zuzana, Netolická, Lucie, Vrána, Aleš |
| Zdroj: |
Central European Journal of Chemistry; Feb2011, Vol. 9 Issue 1, p66-74, 9p |
| Abstrakt: |
The mixed dissociation constant of naphazoline is determined at various ionic strengths I [mol dm] in the range of 0.01 to 0.26 and at temperatures of 25°C and 37°C using ESAB and HYPERQUAD regression analysis of the potentiometric titration data. A strategy of efficient experimentation is proposed in a protonation constant determination, followed by a computational strategy for the chemical model with a protonation constant determination. Two group parameters, L and H were ill-conditioned in the model and their determination is therefore uncertain. These group parameters, L and H, can significantly influence a systematic error in the estimated common parameter pK and they always should be refined together with pK. The thermodynamic dissociation constant p K was estimated by nonlinear regression of {p K, I} data at 25°C and 37°C: for naphazoline p K = 10.41(1) and 10.13(2). Goodness-of-fit tests for various regression diagnostics enabled the reliability of the parameter estimates to be found. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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