Article ID Journal Published Year Pages File Type
215225 The Journal of Chemical Thermodynamics 2015 6 Pages PDF
Abstract

•Protonation constants of adenosine and guanosine were determined.•The dependence of temperature and ionic strength were characterized.•Potentiometric and spectrophotometric methods were used.

Stepwise protonation constants of two purine nucleosides (adenosine and guanosine) were determined at different temperatures (293.15 to 308.15) and various ionic strengths (0.101 to 3.503 mol · kg−1 NaClO4) using a combination of potentiometric and spectrophotometric method. The thermodynamic parameters (i.e. enthalpy change, ΔH, and entropy change, ΔS) of the protonations were calculated at different temperatures using van’t Hoff and virial equations. The dependence of the protonation constant on ionic strength is modeled by a Debye–Hückel type equation and discussed. Finally, the protonation constants of the nucleosides and the enthalpy change of protonations were determined at zero ionic strength.

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Physical Sciences and Engineering Chemical Engineering Chemical Engineering (General)
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