Fluctuations of pH in coastal systems are generally surveyed through potentiometric pH measurements. A new concept of a unified pH scale was introduced with the great advantage of enabling comparability of absolute values, pH_abs, pertaining to any medium. Using water as an anchor solvent, yielding ${\mathrm{pH}}_{\mathrm{abs}}^{{\mathrm{H}}_2\mathrm{O}}$, enables referencing the pH_abs values to the conventional aqueous pH scale. The current work aims at contributing to implement ${\mathrm{pH}}_{\mathrm{abs}}^{{\mathrm{H}}_2\mathrm{O}}$ to saline solutions. To this purpose, differential potentiometric measurements, with a salt bridge of ionic liquid [N₂₂₂₅][NTf₂], were carried out aiming at overcoming problems related to residual liquid junction potentials that affect the quality of such measurements. The ability to measure ${\mathrm{pH}}_{\mathrm{abs}}^{{\mathrm{H}}_2\mathrm{O}}$ with acceptable uncertainty was evaluated using Tris-Tris·HCl standard buffer solutions prepared in a background matrix close to the characteristics of estuarine systems (salinity of 20) as well as with NaCl solutions with ionic strength between 0.005 and 0.8 mol kg⁻¹. The present study shows that for high ionic strength solutions, such as seawater, challenges remain when addressing the assessment and quantification of ocean acidification in relation to climate change. Improvements are envisaged from the eventual selection of a more adequate ionic liquid.

中文翻译：

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实现盐溶液的统一 pH 值

沿海系统中 pH 值的波动通常通过电位 pH 值测量进行调查。引入了统一 pH 标度的新概念，其巨大优势是能够对与任何介质相关的绝对值 pH_绝对值进行比较。以水为锚定溶剂，得到${\mathrm{酸碱度}}_{\mathrm{腹肌}}^{{\mathrm{H}}_2\mathrm{哦}}$, 可以将 pH_绝对值与传统的水性 pH 值标度进行对比。目前的工作旨在促进实施${\mathrm{酸碱度}}_{\mathrm{腹肌}}^{{\mathrm{H}}_2\mathrm{哦}}$到盐溶液。为此，使用离子液体 [N ₂₂₂₅ ][NTf ₂ ]的盐桥进行微分电位测量，旨在克服与影响此类测量质量的残余液接电位相关的问题。测量能力${\mathrm{酸碱度}}_{\mathrm{腹肌}}^{{\mathrm{H}}_2\mathrm{哦}}$使用在接近河口系统（盐度为 20）特征的背景基质中制备的 Tris-Tris·HCl 标准缓冲溶液以及离子强度在 0.005 和 0.8 mol kg ^-1之间的 NaCl 溶液评估了具有可接受的不确定性。目前的研究表明，对于海水等高离子强度解决方案，在评估和量化与气候变化相关的海洋酸化时仍然存在挑战。通过最终选择更合适的离子液体来设想改进。