New Insights into Buffer-Ionic Salt Interactions: Solubilities, Transfer Gibbs Energies, and Transfer Molar Volumes of TAPS and TAPSO from Water to聽Aqueous Electrolyte Solutions

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• 作者：Mohamed Taha and Ming-Jer Lee
• 关键词：Biological buffers ; Solubilities ; Aqueous electrolyte solutions ; Molecular interaction ; Transfer Gibbs energy ; Transfer molar volume
• 刊名：Journal of Solution Chemistry
• 出版时间：November 2010
• 出版年：2010
• 期刊代码：24_00959782
• 类别：en
• 卷：39
• 期：11
• 页码：1665-1680
• 数据来源：sp

摘要

The solubilities of N-[tris(hydroxymethyl)methyl]-3-aminopropanesulfonic acid (TAPS) or N-[tris(hydroxymethyl)methyl]-3-amino-2-hydroxypropanesulfonic acid (TAPSO) in water and in aqueous solutions of CH₃COOK (KAc), KBr, KCl, or NaCl were determined from density measurements at 298.15 K. The solubilities of TAPS in aqueous solution decrease with increasing concentration of the salts (salting-out effect), whereas those of TAPSO increase with increasing concentration of the salts (salting-in effect). The solubility and density data were further used to calculate the apparent transfer Gibbs energies, Δ_tr G, and transfer molar volumes, D_trV_fo\Delta_{\mathrm{tr}}V_{\phi}^{\mathrm{o}}, of these buffers from water to aqueous electrolyte solutions at 298.15 K. The contributions of various functional groups of TAPS, TAPSO, and the related buffers (tris(hydroxymethyl)aminomethane, TRIS, and N-tris[hydroxymethyl]-4-amino-butanesulfonic acid, TABS) to the transfer properties were systematically estimated from the calculated Δ_tr G and D_trV_fo\Delta_{\mathrm{tr}}V_{\phi}^{\mathrm{o}}.